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Author Topic: 'Increasing the Charge' - how piston engine technology provided the power to fly  (Read 68874 times)

Offline tartle

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Why the fascination with piston engines history: simply they are very important. Sidney Camm wrote in his 1966 article 'A Lifetime of Design':
"Looking back over the development of aircraft one is struck by the number of factors that have to be considered --aerodynamics, materials and structures are the main categories and it is fascinating to notice how from time to time, just as we had seemed to reach a stage when progress was slowing down, some new discovery would raise the horizon again. The classic case of this, of course, was the jet engine that was being developed by Frank Whittle. From 1930 it had been obvious that we were approaching the limit of speed with the airscrew engine combination, as in spite of all we could put into airscrew developments, any extra power developed by the engine was wasted due to tip speed losses of the airscrew, and it looked as though speeds between 450-500 mph were about as far as we could go with this arrangement.. Almost overnight the Whittle engine changed this and although we are again approaching a limit due to what may be called the heat barrier, I am sure this will be surmounted.
The point which emerges from this is the dependence of the aircraft design on the production of improved powerplants. This was obvious, even in the days of the Wrights. They first flew, not because their aircraft had any great merits, but because they produced a powerplant-airscrew combination able to lift the somewhat cumbersome machine off the ground. The introduction of the rotary Gnome engine in 1911 was responsible for a tremendous surge forward until the arrival of the Hispano Suiza in line engine which more or less eclipsed the rotary type of engine, although it was still used on a number of aircraft with some success until the arrival of the Rolls-Royce Kestrel in 1927."
This seems a good reason for a technology thread.. this one on piston engines.
A successful technology is only 'successful' if it impacts on an engine in one or more of these categories:
New types and power increases
Changing operational requirements
Environment
Flight operations
Aircraft installations
Repair capability
Life development
Manufacture and suppliers
All these need to move forward if a new technology is to be successfully adopted... it is interesting how the RR racing 'R' engine which gave vast power increases in a short space of time ,,, but only for a life of 1 hour at max output was emulated by the progress of the Merlin, ten years later- but for 100 hours plus life.
« Last Edit: October 23, 2013, 05:40:59 pm by tartle »
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline Tailspin Turtle

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Thanks for the excellent chart and introduction. Another area of discussion is the rivalry between liquid-cooled and air-cooled engine for dominance and the continuous improvement in both that basically resulted in a standoff. (The often repeated statement that the U.S Navy abandoned the liquid-cooled engine in the 1920s is at best a simplification; the Bureau continued to fund liquid-cooled engine development right up to the point where the jet engine made propeller-driven fighters obsolete.) I covered this at some length in my monograph on the XFL-1 Aerobonita published by Steve Ginter since it was central to the Navy's decision to contract with Bell for an Allison-powered fighter in competition with the Vought F4U and the Grumman F5F.

Offline tartle

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 Tailspin Turtle,
 Thanks for the feedback... it can be challenging to know... I am writing because I like to put my thoughts 'out there' but it is useful to know sometimes that 'out there' is not a vacuum!
 The aircooled vs liquid argument is fascinating as it weaves together Capital and Innovation in so many different ways that change with time. What looks obvious to us now is not so obvious in the context of the technical, political and personalities of the date we are focusing on. We tend to underestimate the affect a 'personality' can have on 'distorting' the way things unfold.... hopefully we can tease out some of that as a group.... 'Together We are Better'.
 There are incidents that happen where engineers decide to ignore the rules of political etiquette... I remember being told of an 'incident' in the 1930s involving two senior engineers, British and American aircooled radial experts, who met aboard the Staten Island Ferry, I believe, and by 'accident' took each other’s brief cases as they got off. It so happened each engineer had been carrying blueprints and technical reports on how they had solved a problem that the other engineer was faced with at that time. They did not compete with each other so felt there was no need to feel concerned about giving away trade secrets.... and I would not be surprised if it still goes on ... I certainly had similar experiences in the early 80s.
 
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline AeroFranz

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Tartle, thanks for the chart - definitely stored in my archives in the 'keeper' folder!
All modern aircraft have four dimensions: span, length, height and politics.   TSR.2 got the first three right - Sir Sydney Camm

Offline J.A.W.

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Camm's team tried all 3 big Brit piston engines in their 40's Fury prototype.

The RAF was of course jet-bent by then & didn't order any of the top performing Sabre powered jobs,
but the RN picked up the lesser performing Centaurus powered version for their Sea Fury.

Did the lowest performing (Griffon powered) Fury prototype feature an R-R designed 'power-egg'
of/similar to the type productionised for use in the Shackleton?

AFAIK the Sabre & Centaurus installations were in-house Hawker types, but did Napier ever fit a
Fury airframe with their annular radiator Sabre 'power-egg' set-up?

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Offline J.A.W.

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Here are a couple of interesting period articles from 'Flight', which give comparisons between
air-cooled radial & liquid cooled in-line piston engine installations.

Apart from power-to-weight & cooling considerations, one advantage of in-lines for high speed use
is in exhaust jet thrust, note the ejectors utilized by the high boost ADI equipped Sabre Tempest F6..

http://www.flightglobal.com/pdfarchive/view/1946/1946%20-%201443.html

http://www.flightglobal.com/pdfarchive/view/1946/1946%20-%201455.html
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Offline tartle

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Thrust augmentation was possible on radials just not as easy#;
"THE exhaust thrust augmentor developed for the Convair 240 airplane overcomes cooling drag and adds enough thrust to increase level flight 10 mph and take-off payload 2000 lb."
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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True, T, the way the BMW radial powered FW 190 arranged its exhaust pipes in a thrust enhancing group
was of interest  to Bristol ( Kawasaki & Grumman , too) for their Centaurus/Tempest II installation, but they were never able to offer the several hundred lbs thrust in a positive aero-package that in-lines could achieve.

Was that Convair running a turbo-compound radial?

Other issues for hi-po engines using air-cooling included cylinder head temp control (under & over cooling)
& the difficulty with siting large oil coolers & air-to-air charge inter-coolers.

Funny that many of them ended up running de-facto liquid cooling internally as ADI, either extra fuel,
as per BMW, or Methanol/Water injection..
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Offline tartle

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This particular Convair 240 model was an early (1948) one with Pratt & Whitney R-2800 Double Wasp.
NACA was investigating radial engine thrust, reporting in 1940 on test bed results.. see below. It references two reports, the Oestrich one that started the thinking about thrust augmentation and the Hive's one about RR's use of augmentation.
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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Thanks, T, I have seen a similar NACA test done on an early Spitfire,
 where they swapped the paired ejector stacks for individual pipes,
& which of course - was done in service, later.

As for their '550 mph' thrust rating, that would surely be, as Capt Mainwaring was wont to say..

"Delving into the realms of fantasy, Jones."

The smoothly faired big-bore ejectors fitted to the 2,200+hp V-1650-9 Merlin powered Mustang H
always impressed me as sculptural art & potent thruster nozzles both.

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Offline tartle

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Sculptural art?.... I see what you mean!
and 550 mph...in a dive perhaps!
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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& Here.. 

550mph in a dive? any radial doing that would've been throttled well back, I'd reckon..

Sabre was cleared for 4,000rpm diving though, & Tempest dive limitation in pilots notes was ~550mph..
« Last Edit: March 31, 2014, 10:53:21 pm by J.A.W. »
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Offline J.A.W.

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Jet thrust from in-line exhaust had inherent advantages over radial arrangements.

The in-line row of ejector pipes gave a low frontal area penalty for the grouping,
& also enabled equal length pipes for optimum tuning/back pressure values.

Certainly it was noted as one of the positive factors in FW swapping to a Jumo V12 engine for their 190D.
& by R-R, as part of their reasoning for favouring mechanical supercharging over turbos..

The even spacing of induction system manifolds & even firing orders inherent to in-lines was another advantage,
particularly in high boost applications, whereas uneven mixture/pressure distribution  in radials could be
problematic..

The dynamics of radial crankshaft reciprocation & heavy valve-gear also meant that the sudden, large
movements in revs/boost required in fighter combat manoeuvres were also problematic for radials.

Len Setright wrote about the Napier Sabre being able blip up & down the rev meter like a car engine..
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Offline tartle

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I read an article about 'Tubby' Sielle yesterday; the strapline was 'A centenarian who helped develop the technology to take the fight to Hitler....'
It reminded me of Kranzberg's First Law (of Technology):
  • Technology is neither good nor bad; nor is it neutral.
In the article he talks of horrific pieces of technology that did not work and lives were lost. He did not put this down to incompetence but sabotage. He mentioned two people at Farnboro' who had left leaning politics..... Ben Lockspeiser and F W Meredith (later Managing Director of Smiths -aircraft instrument makers). Both were monitored by security services but not enough evidence to dismiss them. There was a 3rd man, Jack Richards head of instrument dept. He dissented from the decision to fit American Sperry autopilots in RAF bombers, insisting on F'boro's design.... this never worked! etc.
Fascinating stuff in the context of our discussions.
The link only gives a summary so I've scanned my paperr.
« Last Edit: March 10, 2014, 05:45:05 am by tartle »
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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T, does it date from the time that ol' Adolf & uncle Joe were 'thick as thieves' prior to Barbarossa?
& is the Meredith mentioned - the same bloke who did the coolant matrix (radiator) as thrust duct work?
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Offline Basil

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J.A.W.,
the exhaust stubs of an liquid cooled inline are far too short to add the scavenging of the engine They are only optimized for thrust an do nothing to help gas exchange in the cylinders - in contrary - this arrangement adds work to the piston to expell the gases. To support gas exchange from individual cylinders you have to combine different exhaust headers depending on the firing order of the engine (a good example is the "bundle of snakes" exhaust of a Ford GT endurance racing car).
You are right - the firing order of a radial with its master rod and slave rods is not elegant and adds vibration and other engineering tasks. It's a pity that true motion connecting rods (see several Curtiss Wright patents of the 1940s - google patent) did not make it to production.
Regarding the drag of radials I do not agree with you - several of the fastest fighters were powered by radials. Also look at Reno. Of course fuel consumption is usually a little higher compared to liquid cooled engines to regulate cylinder head temperature under high power settings. At least from beginning of the 1940s cooling was arranged in a way that the heated air from engine, oil cooler and charge cooler added a significant net thrust to the total propulsion package. For example, BMW, a leader in providing complete power packages to airframe manufactureres calculated that total cooling drag (including fan power consumption) was more than offset by the additional heat thrust of the powerplant (the calculation I know was done for the stillborn BMW 802). Besides, there are very nice examples of exhaust thrust headers for radials - BMW 801 an the FW 190 (you mentioned it), Bristol Centaurus on the Sea Fury, etc (they also add to expel the hot cooling air from the engine).

Offline tartle

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The same fellow...brings new meaning to the 'Meredith effect'. Vielle is publishing a book 'Almost a Boffin' in June so details might be better in that.
Amazon' s description is:
To continue to live life to the full at 100 years old is quite amazing! In this exhilarating, exciting and at times emotional book EE (Tubby) Vielle takes us through a life which involved several different careers. His early childhood memories draw you into a forgotten world. The threat of hunger during the Great Depression led him away from university to the RAF and flying 150 types of aircraft, not without incident! He guides you through an unexpected account of WW11 which includes mysterious happenings between scientists and some, to date unpublicised, treacherous acts with far reaching implications. His optimism, purpose and enthusiasm are what he sees as the markers for his long and fulfilling life. At age 43, having survived and thoroughly enjoyed 25 years of flying and then being faced with having to serve in desk jobs, "Tubby" Vielle accepted the offer of twice the salary of an Air Marshal, to retire from the RAF and become Managing Director of a company set up to develop and commercialise his invention of an airborne anti-collision system for aircraft (and ships).  He also wrote two novels which were based on his own flying experiences. Both,  were world-wide best sellers and translated into over 20 languages. That, and the sale of the film rights for the first, resulted in Tubby taking up residence in Switzerland, writing more novels and engaging in other interesting pursuits - including becoming involved in trying to recover the Rommel Treasure from the bottom of the Mediterranean Sea and inventing a method of investing which, in ten years, turned £32,000 into over £7,000,000.  Now again resident in UK, he still normally gets up at around five o'clock and enjoys working 10 hours a day!
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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Basil, if you look at high boost supercharged top-fuel dragsters, you will note short individual
dump tube pipes directing high energy exhaust gasses in a useful thrust path..
Forced induction 4-stroke mills do not require the '5th element' cycle of 'extractor'
type tuned-group exhaust manifolding..

At Reno, 'little Limey' Merlins - of a fraction of the capacity of the lazy monstrosity radials - have
dominated in recent years, being able to hack far higher pressures, for longer..

What prodigious feats could a hot-rod Sabre unleash? Plenty - according to Len Setright..

It is true that some worthwhile work can be achieved from a skilful radial exhaust ejector/coolant duct
arrangement, but it cannot match the in-line scheme for thrust or efficiency..

The 'red-under-the bed' Meredith, (  identified by the remarkable ton-up ex-RAF chap as cited by T)
was able to demonstrate that a high speed duct incorporating the liquid coolant matrix was capable
of negating drag penalties, & unlike a big rotund radial, site it in a location remote from the engine..

FW 190, Tempest & Fury all provide examples of airframes that could & did accommodate both radial &
in-line engines of very high output, & in each case showed the superior performance was by using in-lines..
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Offline Basil

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J.A.W., thanks, good points. Especially the TA-152 was much faster with its Jumo 213 than the FW-190 but the airframe was also much refined. Not sure how it would have performed with radial (a late version of the BMW 801 was also intended for the TA 152).
Regarding dragsters - of course you do not need the extractor cycle to have a high performing engine, especially if highly blown, but nevertheless it would add some horsepower. The exhaust thrust of nitro dragsters is that high it contributes a significant downforce to the whole car (I heard about several hundred kilograms).
Of course one advantage of having a radiator is you can place it on that part of the airframe where the thrust/drag ratio is the most advantageous.

Offline J.A.W.

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Thanks B,
& this 'Flight' article may be of interest, it has a table showing cooling drag comparisons done on Tempests.

Chin, leading edge wing, annular radiator, & radial installations.

http://www.flightglobal.com/pdfarchive/view/1946/1946%20-%201441.html

Note though, they are cold ratings, so not taking into account the dreaded 'Meredith effect'..

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Offline J.A.W.

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& the alternative to exhaust jet thrust from ejector exhausts was the turbo-charger, - as favoured by the USAAF..
.. as it allows a consistent altitude/hp rating, & it shows in smooth curved climb/speed performance graphs.

Here is a chart showing the proposed values of the Chrysler V16 in P-47 turbo form.

http://www.weakforcepress.com/CAE/NARAEN001.jpg

The Hemi Chrysler V16 was similar in capacity to Griffon, Sabre, DB 605, Jumo 213.

Note max allowable rpm for dives, 3,840 - close to Sabre territory - in that regard..
« Last Edit: March 13, 2014, 05:36:28 pm by J.A.W. »
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Offline J.A.W.

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Turbos can be fun, but airframes are also important, & woe betide/tiddlers beware..

https://www.vansaircraft.com/pdf/hp_limits.pdf

Sorry, link wont work..
« Last Edit: March 14, 2014, 02:25:26 am by J.A.W. »
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Offline tartle

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Try this.
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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Much obliged T, ta.
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Offline J.A.W.

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Interestingly, the following stands as unintended empirical evidence of the 'Meredith effect'..

 The A. & A.E.E. - were very impressed with the high speed available from their new Mustang,
esp' on its comparatively paltry Allison out-put - &  tried blanking off the radiator for high speed tests,
- only to find it significantly reduced the speed, by ~10mph,

& this was not due to over-heating causing power-loss..

http://www.wwiiaircraftperformance.org/mustang/ag351speed.gif
« Last Edit: March 14, 2014, 10:02:03 pm by J.A.W. »
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Offline tartle

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Terry Hefferman, who was involved in many of the A & AEE trials stated that:
"owing to abnormally high temperatures due to coring (engine oil congealing due to overcooling) during the winter months (tests in January of 1942), tests had to be made with various types of blanks over the oil cooler and engine radiator.
The blanks had a pronounced effect on the maximum level speed:
Max level speed without blanks: 370 mph at 15,000 ft
Max level speed with      blanks: 357 mph at 14,750 ft
It is not certain if this considerable difference is due to increased drag of the blanked off radiators  or a loss of the 'jet' effectof the heated ram air leaving the radiator efflux- possibly a little of both."
« Last Edit: March 15, 2014, 05:24:39 pm by tartle »
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline tartle

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I always felt this 'essay' was a thoughtful contribution to the Meredith effect discussions.
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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Perhaps, but Lee Atwood surely jumps to a few conclusions that appear to ignore certain aspects..

The Mosquito & Tempest I prototypes (both with wing leading edge radiators & high altitude spec engines)
made ~440mph  & ~470mph respectively, in  `43..

On the brute force of well over 2,000hp, perhaps,
- but the Tempest V with chin radiator also made ~460mph on test when running the same Sabre IV..

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Offline J.A.W.

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Attwood's claim of the 'Meredith effect' as the primary reason for the Mustang to be significantly faster than the identically engine/powered Spitfire is also contentious..

The 'laminar flow' wing & generally aero slick airframe is very likely a stronger contender for the speed advantage, &  a like comparison can be made for Typhoon & Tempest.

The Tempest - also with a 'laminar flow' wing was ~20mph faster than the Typhoon on an essentially identical
engine/radiator set-up..
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Offline tartle

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...except the laminar wing on Mustang did not work that well but 'Meredith' did!
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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Well, the Spitfire was reckoned to be built to benefit from the 'M-E'  too, but was ~30mph slower..
..than the Mustang - on the same available power.

So, ~20mph for 'laminar flow' wing/slick aero  & ~10mph for 'M-E' radiator efficacy?

A more likely explanation perhaps, - if extrapolation from the equivalent Hawker evolution holds true..

Esp' when the differential holds for cruise speeds, where the relative contribution from the 'M-E' is less..
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Offline tartle

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Soon I will have written the appropriate chapter of a book covering the period of technology... I'll post a taster then that highlights how these technologies (i.e. tools, techniques and know-how) interplay to give the results we are discussing...tbc
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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Jolly good, T..

& as regards the ~30mph Vmax advantage of the Spiteful over the 20 series Spitfires.

What % was due to the 'laminar flow' wing VS the redesigned radiators/'M-E' efficiency?
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Offline tartle

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Some published material:
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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& from a 'Flight' report on Napier annular radiator testing, an interesting speed/altitude graph.

http://www.flightglobal.com/pdfarchive/view/1948/1948%20-%201660.html

Note the line showing the standard Tempest F6 with chin radiator,
- higher (+17.25lb on ADI) boost levels give brute force (3,000+hp) for best speed at low level,
only to be clawed back at higher levels by the lower drag (higher 'M-E'?) annular set -up.

However the Vmax difference is ~same as between the Hawker leading edge wing & chin radiators.
« Last Edit: March 17, 2014, 06:42:56 pm by J.A.W. »
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Offline J.A.W.

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& for comparison - a graph showing Tempest II performance on test - Centaurus radial at +12lbs boost.

http://www.wwiiaircraftperformance.org/tempest/tempestii-cfe-appd.jpg

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Offline AeroFranz

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I apologize for a quick digression from the fascinating discussion -
Tartle, the pics you posted are from Spitfire: the history (I presume). It looks like a worthwhile book to get.
I searched the book and Amazon gives a frightening price of $336 for a 2001 edition. There is also a more reasonably priced 1984 edition. Does anyone know if the 2001 edition differs significantly? Thanks!
All modern aircraft have four dimensions: span, length, height and politics.   TSR.2 got the first three right - Sir Sydney Camm

Offline tartle

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Yes the second edition is a I borrowed mine from local library and copied a few bits!
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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Yeah T, & good on ya, too, but do you know..is it worth the price premium data-wise?
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Offline tartle

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Depends what you are after... it is the most comprehensive history of the Spit and full of technical data. I have attached what someone said about it:
How then to tell the story of such an important fighter? Many have attempted, but until Key Publishing commissioned a new work in 1987, there was nothing – in one volume – that did justice to this iconic aircraft. Here you can see the result; the front cover of the 1st edition of this book is shown (my own copy lies around 4 feet away in one of the bookcases). ‘Spitfire:The History’, Eric Morgan & Edward Shacklady, Guild Publishing (by arrangement with Key Publishing), 1988, ISBN 0946219109, is a meaty book (Quarto;634 pages) and, according to the Foreword by Jeffrey Quill, the test pilot who undertook most of the testing of the prototype, K5054,‘…it is not a book for light reading, but will be an essential on the shelves of serious aviation historians.’ Eric Morgan, who served as an Electronics Officer in the postwar Royal Air Force, and Edward Shacklady, the former Editor of ‘Air Pictorial’ and the founder of Profile Publications, were the ideal pair to deal with this important subject. Containing chapters with titles such as ‘Low Level Photography’, ‘A Useful Interim Type’ and ‘Blow The Spitfire’, this tome covers all variants, all color schemes, and every major and minor technical detail. To my amazement, I found that the book lists every single aircraft of the type, more than 20,000 of them, and what happened to them (admittedly, in very small type). I shall leave it to Jeffrey Quill – the ultimate Spitfire pilot – to give the final assessment, ‘As definitive a history of the Spitfire as is ever likely to be written’

so you pays your money if that's what you want!
« Last Edit: March 19, 2014, 05:38:58 pm by tartle »
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Offline J.A.W.

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I apologize for a quick digression from the fascinating discussion -
Tartle, the pics you posted are from Spitfire: the history (I presume). It looks like a worthwhile book to get.
I searched the book and Amazon gives a frightening price of $336 for a 2001 edition. There is also a more reasonably priced 1984 edition. Does anyone know if the 2001 edition differs significantly? Thanks!


T, have you perused both editions ( 1984 & 2001) - or know of significant differences -as mentioned by A-F?

I would also be interested, but not at $336!,  .. s'pose I could try a library inter-loan request though..
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Offline Orionblamblam

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I would also be interested, but not at $336!,  .. s'pose I could try a library inter-loan request though..

abebooks.com has an '87 for $58, an '87 for $71, an '01 for $104, an '88 for $109. On up to over $400.
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Much obliged, Obb.

The enduring fame/popularity of the Spitfire clearly at work, there.. eh?
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Offline tartle

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What is a book worth? Depends on the individual need. I would love to have 'Spitfire: The History' 2nd edition by morgan and Shacklady as the technical bible; but I live without it, borrowing it through inter-library lending. having purchased ' The Spitfire Story'  by Dr Alfred Price as an affordable alternative, supplemented by Ken Delve's 'The Story of the Spitfire: an operational and combat history' (also needed if you buy M&S) and then 'Decisive Duel' to fill in gaps... if following an individual aeroplane I use this site instead of M&S then its off to Kew to expand the information....... as I said " you pay the money when you makes a choice" or as Coldplay wrote in 'Fix You'
"When you try your best, but you don't succeed
 When you get what you want, but not what you need
 When you feel so tired, but you can't sleep
 Stuck in reverse"
Hope this ramble helps.... none of the books gave me 'what I need' but certainly 'what I want(ed at that moment in my researches)' which is information that tells the story of an individual Merlin Mk XX, 45 and 66 engine a colleague has had restored plus his replica Spitfire Vb; oh and a Griffon and Sabre..etc.
Hope this helps?!
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Offline J.A.W.

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Thanks - yes, T.

I find A. Price to be an openly partisan Spitfire fan however, which tends to cloud the veracity of his stuff..

Mind you, Len Setright is an unabashed/passionate Napier fan like-wise..

& David Isby has kindly made many of his interesting source documents available - on his site.

http://www.SpitfirevsBf109.com
« Last Edit: March 19, 2014, 07:29:54 pm by J.A.W. »
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Offline AeroFranz

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Thanks for the comments, T, and thanks to OBB for the link to abebooks. I am more interested in technical diagrams than operational history and where each individual airframe ended up, but it seems like the book has both.
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Offline Orionblamblam

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The enduring fame/popularity of the Spitfire clearly at work, there.. eh?

Lots of books become insanely expensive after they're out of print. Sometimes it makes sense, but often it almost seems more like some sort of money laundering enterprise. I've seen the *same* book available for sale for nearly ten years for the same ridiculously high price, but available elsewhere in some numbers at a fraction of the price. Shrug.
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Well I never.. ..sounds plausible though, esp' if the same book stays on 'sale' at a ludicrous price..

Now, if they are being bought at those prices, I 'd best check my home contents insurance values..
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Offline tartle

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AeroFranz.... Try this book if you are diagramish... J A W why don't you write your own book on 'where are they now the based on the list here.
Now I suggest we tack back to the real meaning of 'increasing the charge' and go here if we want to discuss book pricing, value etc.
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Where they are now, T? 

Burma wasn't it?
Plenty of 'boost' involved with that set-up..

Mind you, a scan of the Nile riverbed off the jetty at Khartoum..
.. where the surplus Sabres were dumped - after the Tempest F6 tropical trials could be worth a try..

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Stanley Hooker reckoned that.. 4-strokes = 1 stroke for power & 3 to wear the engine out..

So a big 2-stroke article..

http://www.autospeed.com/cms/article.html?&title=Napier-Nomad&A=112994

& a small 2-stroke article, but it too applies to flight power..

http://www.hirth-motoren.de/en/2-stroke-logic.html
« Last Edit: March 20, 2014, 02:32:51 am by J.A.W. »
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Offline LowObservable

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Nice article. If only there was an operational requirement today for a JP-5-burning, ultra-efficient engine that could be scaled down to <500 shp...


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Yes, L-O, & a pity it aint done - perhaps due to US product liability issues?

& for a more conservative viewpoint..

http://www.epi-eng.com/piston_engine_technology/engine_technology_contents.htm
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Offline CJGibson

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For a more light-hearted, but very informative, work on engines, try the pre-Bond villain Robbie Coltrane.



The supercharger episode is superb.




Chris

Offline tartle

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Really good book with the tv series... will buy my grandson a copy when he can read!
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Offline tartle

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JAW... great find!
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Offline J.A.W.

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Ta, T.

& for a mechanically contrived coordinated engine/prop control system..

- BMW 'Kommandogerat', or how to reduce some of the workload of a radial fighter engine for a sole operator.

http://www.focke-wulf190.com/images/bmwkommandogeraet.jpg
« Last Edit: March 22, 2014, 06:46:07 pm by J.A.W. »
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Offline J.A.W.

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This running example of a Continental IV 1430 'Hyper' mill seems to tolerate a bit of 'blipping'..

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An article for those interested in engine firing orders..

http://www.enginehistory.org/fo/FO.shtml
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Offline CJGibson

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Tartle / JAW,

What effects, if any, do cross-over exhausts have and do they have any advantage (improved power, improved efficiency) or are they detrimental to performance. They were fitted to the Merlins on Canadair North Stars for noise reasons, but I wondered what difference they made to the engine operation.

Thanks

Chris

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CJG, if you refer to posts #10/11 in this thread - you will see a high-speed thrust ejector exhaust.

Any variation on this scheme ( unless as a dedicated alternative thrust-use system such as a turbo)
would be less efficient, power-wise.

However, as you noted, there may be other priorities, viz - noise abatement, or flame damping.

These set-ups invariably reduced available jet thrust - but were deemed needful for operational reasons.
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Offline J.A.W.

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Bill Gunston wrote a comprehensive Napier Nomad article for 'Flight'.

Note the SFC efficiency as graphed..

http://www.flightglobal.com/pdfarchive/view/1954/1954%20-%201222.html

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Offline tartle

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see also our site here and thread here.
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Here's a novel piston-power flight application..

http://www.pattakon.com/pattakonFly.htm
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Offline tartle

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In 1940-41 the high altitude Wellington was being developed... it was to be capable of flying at 40,000 ft with a significant bombload. Original planning called for 2 turbosupercharged Hercules VIII; but RR were asked to work on a back-up version of Merlin-the 60 series- with 2 stage supercharger... mechanically driven... RR did the performance maths and risk assessment of using a turbocharger and decided not to embark on a development programme for another technology (war raging, BoB etc.).
In 1941 Whittle and bone wrote a paper suggesting the use of a scaled 'Gyrone' engine as a special form of supercharger where two Merlins were supplied with air from the 'Gyrone' compressor... the Merlins' exhaust was then ducted back to the combustion chambers and additional fuel burned to supply energy for the turbine. Any excess energy could then be discharged to generate thrust. First reading of paper indicates that:
A Wellington so equipped was calculated to have a speed of 341 mph at 37,000 ft vs the 'conventional' Merlin powered high altitude Wellie that travelled at 271 mph at its service ceiling of 31,000 ft. This and other work ( RAE sponsored work at Bristol/Fraser and Chalmers; RR and Brown-Boveri unearthed) no doubt informed the creation of an OR for the Napier E145 Nomad which was of similar arrangement... but the engines were 'squashed into one!
Sketch of arrangement attached. Project not proceeded with. The Wellington was superseded by the Mosquito and the resources for Gyrone were directed at getting a working gas turbine for the Meteor etc.
(intriguing what can be unearthed over a day at Kew, some other stuff to follow)
« Last Edit: March 30, 2014, 04:28:21 am by tartle »
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Offline tartle

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When looking at engines it is worth thinking what limits the engine life... there are quite a few things of course limit mechanical reliability but a crude measure is mean piston speed.... defined (imperial units) as MPS= RPM*S/6 ft/min..... S is stroke in inches.
The limit for a service aero engine is 3000 if reliability is to be maintained with good TBO. The RR 'R' engine had an MPS of 3500 and could be relied on to run for 1 hour. Merlin, Griffon and Crecy were all below 3025. Sabre was 3000 to 3166. Industry accepted figure for max reliable MPS is 3000. It would be worth a detailed look at the individual parameters of Sabre vs Merlin, say, to get a feel for what problems were built-in and what were due to lack of development before production. GP cars tend to 3400 MPS.
The RR Eagle II which we discussed in detail elsewhere on this site had a MPS of 2990 which shows how RR's service experience was built in to the initial design of the engine which some people assume to be a copy of sabre but was designed before RR had access to Napier's design... the OR was to develop a similar configuration of greater power.
« Last Edit: March 30, 2014, 06:12:17 am by tartle »
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Offline J.A.W.

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In 1940-41 the high altitude Wellington was being developed... it was to be capable of flying at 40,000 ft with a significant bombload. Original planning called for 2 turbosupercharged Hercules VIII; but RR were asked to work on a back-up version of Merlin-the 60 series- with 2 stage supercharger... mechanically driven... RR did the performance maths and risk assessment of using a turbocharger and decided not to embark on a development programme for another technology (war raging, BoB etc.).
In 1941 Whittle and bone wrote a paper suggesting the use of a scaled 'Gyrone' engine as a special form of supercharger where two Merlins were supplied with air from the 'Gyrone' compressor... the Merlins' exhaust was then ducted back to the combustion chambers and additional fuel burned to supply energy for the turbine. Any excess energy could then be discharged to generate thrust. First reading of paper indicates that:
A Wellington so equipped was calculated to have a speed of 341 mph at 37,000 ft vs the 'conventional' Merlin powered high altitude Wellie that travelled at 271 mph at its service ceiling of 31,000 ft. This and other work ( RAE sponsored work at Bristol/Fraser and Chalmers; RR and Brown-Boveri unearthed) no doubt informed the creation of an OR for the Napier E145 Nomad which was of similar arrangement... but the engines were 'squashed into one!
Sketch of arrangement attached. Project not proceeded with. The Wellington was superseded by the Mosquito and the resources for Gyrone were directed at getting a working gas turbine for the Meteor etc.
(intriguing what can be unearthed over a day at Kew, some other stuff to follow)

Aye T, & the Luftwaffe were flying very high altitude Jumo Diesel powered Ju 86 recce-bombers too,
Napier had the licence to build those aero-diesels, & utilized their tech for Deltic & Nomad.

& it took Stanley Hooker's 2-stage supercharging Merlin performance at high altitude in a Spitfire to
intercept those Junkers, after they had been quite troublesome.

The RAF did try turbo-charged B-17s for very high altitude attacks, but found them of little use..
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Offline J.A.W.

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When looking at engines it is worth thinking what limits the engine life... there are quite a few things of course limit mechanical reliability but a crude measure is mean piston speed.... defined (imperial units) as MPS= RPM*S/6 ft/min..... S is stroke in inches.
The limit for a service aero engine is 3000 if reliability is to be maintained with good TBO. The RR 'R' engine had an MPS of 3500 and could be relied on to run for 1 hour. Merlin, Griffon and Crecy were all below 3025. Sabre was 3000 to 3166. Industry accepted figure for max reliable MPS is 3000. It would be worth a detailed look at the individual parameters of Sabre vs Merlin, say, to get a feel for what problems were built-in and what were due to lack of development before production. GP cars tend to 3400 MPS.
The RR Eagle II which we discussed in detail elsewhere on this site had a MPS of 2990 which shows how RR's service experience was built in to the initial design of the engine which some people assume to be a copy of sabre but was designed before RR had access to Napier's design... the OR was to develop a similar configuration of greater power.


The piston speed 'limit' has been a bit rubbery for a few decades, but in general it is a fair TBO indicator.
BMEP is perhaps a more meaningful number.

Funny that Ford's attempt to 'improve' the Merlin got stuck on the basic bore & stroke dimensions.

& R-R itself, while adept at developing their conservative V12 Merlin/Griffon, failed to match the
Napier Sabre with their radical 24cyl Vulture & would-be  'improved' Sabre-type Eagle 22..
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Offline J.A.W.

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Perhaps it is a bit of a generalisation, but the conservative R-R approach to undersquare bore to stroke
architecture is something both Honda & Audi have continued with in automotive engines.

R-R conrod strength/bigend bearing issues are another matter, & the Reno race Merlins run Allison rods..

Mention of the long-stroke 36lt R-type R-R race engines running high pressures/MPS at the cost of ropy crank
& short TBOs brings up the comparison with the Napier Lion, which took the R's land-speed record.

For a WW1 engine design to be powering the LSR holder ~40 years after it 1st ran - was pretty good.
The Lion, an oversquare, slipper-piston DOHC mill, developed ~1,000hp over its initial output for the LSR,
again, a good effort for 24 litres..

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Offline tartle

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The Reno racing Merlins do run at around an MPS of 3799 so you would expect some mods to be needed! The 'R' story is really a precursor to what happens at Reno today. As to the Eagle not being as good as Sabre... maybe the lack of development time is something to do with that.The use of MPS and semi-dimensionals based on that seem to work for Grand Prix engines so I would like to see the evidence that the parameter, as a generalised predictor, has lost its bite.
Arthur Rowledge designed both the Lion and the 'R' engine.
« Last Edit: March 30, 2014, 04:41:39 pm by tartle »
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'Grand Prix' engines these days are highly regulated exercises in SFC,
-so are more about economy than out-right power (with TBO being part of the economy equation), T.

The current F1 mills do have some parallels with your Whittle diagram though.

Mind you, 2-strokes with their inherent power density/mass/BMEP advantages - have been long since banned..

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Offline J.A.W.

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The final (pre-ban) 2-stroke G.P. motorcycles were producing a reliable, tractable ~440hp/ltr.

Naturally aspirated, without forbidding MPS.

Albeit, they were highly developed units - using the principles worked out by ah, 'Nazi rocket science'..

Viz.. W. Kaaden's V1 sonic exhaust pulses via 2-stroke piston/reciprocation power transfer, effectively..
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T, do you have any info on S.Tresilian's hi-po X-16 proposal for R-R?

This fairly recent Lamborghini V12 marine racing mill must be reliable & have a reasonable TBO under stern use.

8.2ltr, 1100hp @ 7,500rpm - sans forced induction..

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Offline tartle

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JAW,
This reference by very trusted authors...Piggott and Taulbut... indicates a maximum bhp/litre of 360. As I don't wish to get into a motorbike thread (not being where I want to go) may I suggest Taulbut's site is a great source of technical analysis of GP car engine design over the years. With the odd reference to aero engines.... which reminds me...
As we have seen from my other posts, I am intrigued by how the history of the development of the axial gas turbine compressor took shape... from Griffith's H1111 report in July 1926 to the Metrovick F2 in WW2...
Also I read a footnote in a GT Handbook that refers to Brown-Boveri completing a RR purchase order by delivering a 2.5 PR 190 hp axial aircraft supercharger.
Imagine my pleasure at finding this letter, below, at Kew... which raises a lot of supplementary questions!
Also Bristol was going down a similar track using an axial supercharger designed at RAE and constructed at Fraser and Chalmers (a GE subsidiary in Kent) Having been invited to do so by the Ministry.. the second letter below kicks off the cooperation.
Tresilian's stuff covered in another thread... try the search facility.
« Last Edit: March 31, 2014, 12:12:34 am by tartle »
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Offline J.A.W.

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T, why would Tresilian's stuff not belong on this thread? Was it another R-R technical no-go?

& notwithstanding your useful G.P. info posted.. (& I'm not referencing motorcycles per se)..
..the 125cc G.P. Aprilias were rated @ ~55hp in their final year - 2011, & were limited to 6 gear ratios,
which gives a clue to their tractability - even at those outputs.

Obviously supercharging, whether by forced induction or chemical pressure boosting will give more power.
Note that the Napier Sabre max power rating was for take-off, a sign of a strong mill..
 
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Offline tartle

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If we were starting out on Tressy now we might put it here... but this thread is an outgrowth of the first one not vice versa... hindsight and all that would change every thread on the site. It is a forum where discussion drives... I think... but the moderators may have a clearer idea to guide me.
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Well, T - in post#63 - you included a couple of other post subjects into this thread..

Tresilian's design was for a fairly high BMEP design, but few X-types seem to pan-out as practicable.

Rowledge's W12 Lion was 3/4th of an X though, & worked well, - maybe that triple prime harmonic at work?

The 8.2 V12 Lamborghini bore/stroke is 97.7 x 89mm, & likely strong enough to substitute RPM for boost..
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Roy Fedden's review of the WW2 German piston aero-engines includes this comment re final Jumo 213 type..

"...appeared willing to accept an abnormally high piston speed & RPM."

Viz - 165mm (~6.5in) stroke turning 3,700rpm ( TBO?).

4-stroke mills are inherently 'lazy', thus require high rpm &/or pressures to produce good work..
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This clip (skip to ~3:30 for best effect) dynamically shows the exhaust jet/firing order of a 2-row radial..

« Last Edit: March 31, 2014, 10:58:01 pm by J.A.W. »
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« Last Edit: April 01, 2014, 04:27:55 pm by J.A.W. »
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Very cool video - there are actually shock diamonds visible in the exhaust flames if you look closely!

Offline tartle

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JAW, Trident...
Is that good?
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Not good for night flying, glare disrupts pilot vision & attracts the view of enemies..

As a matter of contrast - the sleeve valve engines were noted to produce much less - exhaust flame.
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Which sleeve-valve engine compared to what?
I only ask this after a 'hard day at the office' which reminded me of over simplifying our comparisons e.g. musing  here.
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Offline J.A.W.

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Compared to poppet valve, T.

The Fury in the vid has had its Centaurus replaced by a Wright mill.
From Tempest II (Centaurus) flight trials, re night flying..

"The almost total absence of exhaust glare is a particularly pleasant feature of this aircraft."

& also - refer: paragraph 4, in this Sabre article..

http://www.flightglobal.com/pdfarchive/view/1946/1946%20-%201455.html
« Last Edit: April 04, 2014, 03:28:39 pm by J.A.W. »
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Offline J.A.W.

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over simplifying our comparisons...  here.
[/quote]



Well T, at the risk of appearing over-simple..

..Don't just about all engines that work by gas transfer - essentially seek efficiency in inertia management of
the working medium, by means of best maintaining flow over time, via low-loss ducts & pressure/velocity control?

Some, like most piston engines will transfer primary power mechanically,with maybe, a bit of extra heat re-use.. 
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Offline tartle

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I have nothing to add on simplistic... but adopting a different technology i.e. sleeve valves had a beneficial effect on exhaust flames; but of course there was a bmep trade-off to achieve that if I might be over simplistic... as they say we rarely get something for nothing,,, but it is very interesting how ten years of development changes the balance of outcomes.
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Offline J.A.W.

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True T, & while from 1935-1945 sleeve valves had got to demonstrate their considerable advantages,
these were rendered less so by the ready availability of high octane fuel, then swept aside by turbines..
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Offline tartle

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The fuel and the sodium filled valves, Fedden told me in 1965, were the two technologies that closed the gap and reduced the competitive advantage of the sleeve valve over conventional valves. It took so long to 'crack' the manufacturing technology required to produce the reliability of the sleeve in opertaion that valves had closed the gap and the gas turbine swept it all away!
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Offline J.A.W.

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Here is a relatively recent appraisal of the sleeve valve VS poppet valve aero-engine debate.

http://www.enginehistory.org/members/articles/Sleeve.pdf

I note that the NASA article on the modern application of a turbo-compound 2-stroke Diesel aero-engine
also reiterated the potential advantages of the sleeve valve in their considerations.

I did enjoy working the smooth operating cycle of the Bristol Hercules sleeve valve cylinder on public
display at the RNZAF museum.
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Offline tartle

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JAW,
The sleeve valve text is a great example of a thoroughly researched paper; the cost comparison figures he wrote that Rod Banks said are in fact really reliable figures from the work of Devons who was the planning guru at the Ministry through the last half of WW2.
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Offline J.A.W.

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I'd reckon T, that while interesting, it could've done with a good technical editing..

One example, the weak comparison of relative compactness - in liquid cooled engines.

It is not too difficult to measure the difference between them per complexity above the piston,
- since cylinder-head-wise, poppet valve mills are significantly more dimensionally massive there,
with having to carry  camshaft, rockers, valves, springs, ports, manifolding & etc..

& again costs-wise, how many quid would you put on stopping the Focke-Wulf attacks & 800+ V1s
crashing on London, or not knowing if the likes of the Jumo 222 would show up in numbers?

Len Setright wrote that the Centaurus was good for a 3,000hr TBO..
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Offline tartle

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Who will do the 'improvement' then?
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Who will do the 'improvement' then?

If you mean via actual flying of piston engines T,

 I guess that is up to the contractor/tender winner of a defence specification program?

Or - if it is simply an academic thesis matter, well, then his supervisor needs a kick up the jacksey..
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Offline J.A.W.

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Unless.. Ricardo has a Crecy test unit in storage - that they can do a 21st century make-over on?
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R.J. Raymond in his report (post #90) appears to have little hands on experience with engines..

His analysis is a bit lacking in parts..

Obviously an H engine with 2 crankshafts &  24 cylinders (Sabre) is likely to weigh more than a V12 (Griffon)
of ~the same cubic capacity - but the output potential in power to weight terms - more than compensated.
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Offline tartle

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R.J. Raymond in his report (post #90) appears to have little hands on experience with engines..

His analysis is a bit lacking in parts..

Obviously an H engine with 2 crankshafts &  24 cylinders (Sabre) is likely to weigh more than a V12 (Griffon)
of ~the same cubic capacity - but the output potential in power to weight terms - more than compensated.
I suggest that you email him and ask what his experience given all the technical papers he has written his email is
 robertjraymond@gmail.com
P.S. what is the protocol for this forum?
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Offline J.A.W.

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Thanks T, & I did note that he indicated that he would welcome comments on his work.

But given that it was published almost 10 years ago, somehow I doubt that any critique at this point
- would be novel - to RJR..

As for this forum, a discussion of the cogent issues ought to be of interest..
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Offline J.A.W.

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R.J. Raymond  also makes a bit of an incorrect assumption - as he put it - "...one would suspect..."

Re: the ports cut into sleeves being less effective than the "nozzle"-like poppet valve porting.

Of course poppet valves are limited in allowable lift by cam/spring matters,
- or before damaging contact possibly occurs with piston, or opposing valve/s..
& the "nozzle" is largely restricted into an annular orifice by the obtunding poppet head..

As an example, the final 2-stroke 125cc Aprilia G.P. single cylinder motorcycle engine was capable of flowing through its sleeve ports what the final 4-stroke OHC 500cc Norton G.P. single cylinder poppet engine could, yet to greater max power output..
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Offline J.A.W.

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This well researched & written P&W R-2800 development article..
..includes reference to poppet valve gear inertia contributing to NVH issues..

http://www.enginehistory.org/NoShortDays/Development%20of%20the%20R-2800%20Crankshaft.pdf
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Offline Artie Bob

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I do not know if Kimble is still alive, but if one does a little research, they will probably find he was the R-2800 test stand engineer  that lived with that engine from the time he joined P&W shortly before WWII and stayed with it all the way through the war. Thus, his "well researched" article could actually have been written in the first person.  What he does not say in this article are some of his test stand achievements with the R-2800, including a 100 hour test at 3000hp rating and a final peak output test at 3800hp. He reported that all of that test stand development had been accomplished with a single "stock" R-2800 except for the outsize supercharger and water injection (Hartford city water with no alcohol).

Best Regards,

Artie Bob 

Offline J.A.W.

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Thanks A-B, the article does mention a 'moment' in the dyno room when a test engine failed catastrophically..

Alcohol was added to ADI primarily as an anti-freeze agent for flying at low temperature altitudes,
- so for ground/laboratory testing - it was not needed.

 &  cooling/supercharging constraints were likewise absent, so a mill could be really wrung out on lab test.
« Last Edit: April 14, 2014, 03:47:53 pm by J.A.W. »
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Offline Artie Bob

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After posting my note on the R-2800, I realized that I had done this from memory of a phone conversation with the P&W engineer some years ago and I couldn't lay my hands on either my phone notes or other back-up material.  The information is I believe correct as told to me but it is not certain if Kimble was the P&W engineer or whether it was Kimble who had put me in contact with him.  I will go through my material and post a correction if needed. 
Relative to the use of alcohol added to the water injection fluid, the point here is that in addition to acting as antifreeze, IIRC, it can also further enhance the power output, so the power increases in actual service with the R-2800 were possibly more than predicted at any given boost pressure using water injection. The point made by the high output testing was that mechanically, the R-2800 was very difficult to break and had the ability to run reliably after heavy overboost (which saved many pilots during that period).
I began to fly and spend most of my waking hours at airfields in the early 1950s, earning my keep fueling, moving aircraft and starting engines with dead batteries (a 420hp Wright was the largest I hand propped).  Some of my most vivid memories are of WWII surplus transports taking off overloaded on hot days nearing the end of the runway, trailing blue flame visible 20 to 30 feet behind the wing.  One can only wonder what manifold pressure produced this effect.  I never saw an accident, but often the aircraft could be seen a mile or more beyond the runway, just beginning to climb out of ground effect.

Best regards, 

Artie Bob   

Offline WJPearce

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I think we are talking about two different articles here. Kimble D. McCutcheon is the president of the Aircraft Engine Historical Society and I am fairly certain he never worked for P&W. However, he did write the article mentioned above and also the article below that involves Frank Walker. Walker was the P&W test engineer who ran up an R-2800 to 3,800 hp, in competition with the R-4360, and never blew an engine.

http://www.enginehistory.org/Frank%20WalkerWeb1.pdf

Regards,

Offline J.A.W.

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Great article B, - & wow, those R-2800 were real thirsty - 275 gallons per hour WFO!
.. no wonder those series production P-47s had to keep adding fuel tankage.

Interesting too, how they only wanted the alcohol in the ADI as anti-freeze
& avoided the isopropyl-type which did upset the fuel mixture ratio.

Although BMW ran a direct fuel injection system that discretely fed each cylinder on their radial,
they also used an extra injector squirting high-test C3-type fuel into the supercharger eye - as ADI..
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Offline tartle

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This is the bible on piston aero engine and fuels development written by Schlaiffer and Heron, frequently quoted on this board.
I obtained my CD copy from weak force press.
It is pretty accurate overall and is a good starting point but its assertions should be tested as there can be other interpretations now we have more government papers in the public domain... Heron graduated and researched at Manchester University before moving to the Royal Aircraft Factory at Farnborough. In the twenties he may have been keen on attracted Jimmy Ellor away from RAE (also a Manchester grad and researcher)
but Fell arranged for RR to make him a good offer with consequent benefits to increasing the charge' in RR engines.
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Offline tartle

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Following up on digging into Kew in order to chart the history of supercharging in more detail than Schlaifer and Heron and on another website I started the journey through WW1 to just post-war. Extending the timeline has taken me to an interesting RAE turbocharger design circa 1934 for the 'High Altitude Kestrel'. This is shown in section below. An installation drawing of that turbocharged Kestrel is also shown below. The aeroplane is a high-altitude monoplane... but I am unsure what that is.... anyone have an idea what it could be?
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline JFC Fuller

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Tartle,

The only thing that comes to mind is the Bristol Type 138B, it was a follow on to the original Type 138 and was to be fitted with the Kestrel in supercharged form though I can see a turbocharger being considered for obvious reasons.

Offline J.A.W.

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This is the bible on piston aero engine and fuels development written by Schlaiffer and Heron, frequently quoted on this board.
I obtained my CD copy from weak force press.
It is pretty accurate overall and is a good starting point but its assertions should be tested as there can be other interpretations now we have more government papers in the public domain... Heron graduated and researched at Manchester University before moving to the Royal Aircraft Factory at Farnborough. In the twenties he may have been keen on attracted Jimmy Ellor away from RAE (also a Manchester grad and researcher)
but Fell arranged for RR to make him a good offer with consequent benefits to increasing the charge' in RR engines.



Too right - 'assertions should be tested' - T.
 
& while I couldn't possibly comment on who was 'keen on' who, or 'attracted/arranged/offer/benefits'-wise..
..by odd coincidence, the Kevin Cameron TDC column in the April 2014 issue of Cycle World mentions this..

Kevin Cameron is a veteran engine tuner & gifted technical writer, & relates..

"I don't want to put out nonsense, so I try hard to speak the truth. My friend Graham White, author of
'Allied Aircraft Piston Engines of WW 2' & two other wonderful, thick engine books, was dismayed when
prickly, retired, & very experienced engine men crabbed over the inevitable few small errors in his 1st book.

I asked him to consider the statistics. The more you say, the more rubbish you must inevitably utter.
Every manufacturing process has a scrap rate, & writing is no exception.

So, over the long haul, you must accept fallibility & criticism.
& resolve each time to do better."

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Offline tartle

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As Samuel Becket the playwright expressed it:
Ever tried. Ever failed. No matter. Try again. Fail again. Fail better.
"A second machine was ordered as the Type 138B in 1935. This was to be a two-seater powered by a Rolls-Royce Kestrel S engine fitted with a similar two-stage supercharger installation and generating 500 hp (370 kW). The airframe was delivered to Farnborough Airfield in 1937 for completion but the engine installation was never completed."
« Last Edit: April 23, 2014, 01:46:42 am by tartle »
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Offline J.A.W.

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Early aero-engine turbochargers were tested on Liberty V12s in America, 1918 at Pikes Peak altitude..

http://www.enginehistory.org/superchargers.shtml

& a little later - on the Napier Lion in Blighty, but metallurgy/pressure control issues were problematic..

Here is an interesting view of the innards of a (Napier) Lion..

http://www.apss.org.uk/projects/completed_projects/lion/index.htm
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Offline J.A.W.

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Interesting that P&W developed their R-2800 as a fighter mill for both USAAF & USN, (turbo'd for Army use).

This article claims the R-2800 installation in the USN Corsair provided significant exhaust jet benefits..

Viz,  thrust worth ~190lbs/210hp & ~20mph to Vmax..

http://legendsintheirowntime.com/F4U/F4U_IA_4508_DA.html
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Offline J.A.W.

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Chrysler Corp turned down the British request to build Napier Sabres - in favour of the Curtiss-Wright R-3350,
-for the B-29 program.

This was a huge undertaking ( ~$100,000 for engines per plane) & by hard engineering toil the Mopar guys
got the TBO to rise above ~200 hours.. ..see the exploded view of the troublesome radial here..


http://www.allpar.com/corporate/factories/chicago.html
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Offline tartle

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Jimmy Ellor was looking at turbos during WW1 . Towards or just after the end of the war RAE schemed several generic gear and turbo driven superchargers and these designs were adapted to fit various engines such as Lion and Liberty ... lack of test beds meant these then took to the skies.
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Offline J.A.W.

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T, were the pioneering efforts at supercharging directed at increasing service ceilings?

Or as out & out power enhancement?

Obviously the racing Schneider Trophy/air-speed record planes wanted max sea-level power..

.. But the turbo-charged service engines were noted for maintaining a steady boost pressure to a primary mechanical supercharger so as to maintain performance over a fairly high altitude range - due to the turbo's  ability to compensate by 'spooling up' (to the rpm limit) - as atmospheric pressure dropped, but were not known for high performance on the deck, & the US turbo fighters (P-38 & P-47) could not make enough low level speed to effectively run down V1 cruise missiles.. 
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Offline tartle

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I believe the first superchargers for boosting sea level performance were the Schneider trophy machines.... before that it was really about restoring sea level ratings higher up in altitude. I am accessing performance reports on the turbo lion in a day or two so that I hope will enlighten us both!
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Offline JFC Fuller

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Chrysler Corp turned down the British request to build Napier Sabres - in favour of the Curtiss-Wright R-3350,
-for the B-29 program.

Said Chrysler Sabres would have been for 750 Bell manufactured Hawker Typhoons. Was anywhere else ever considered for Sabre manufacture?

Offline J.A.W.

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Sabres built in Acton, & Liverpool.
Maybe the Beaverbrook memoirs would have some more info on the matter?

Perhaps the US deal fell through on proposed US Sabre usage?
(Albeit - there may have been some trust issues with Bell, after the RAF Airacobra debacle).

Certainly the USAAF were impressed by the Typhoon/Tempest.
- & are responsible for the saving the sole intact surviving Typhoon..
« Last Edit: April 23, 2014, 02:52:58 pm by J.A.W. »
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Offline J.A.W.

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« Last Edit: April 23, 2014, 04:11:01 pm by J.A.W. »
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Offline mz

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Some of the solutions seem so odd.

Why was the P-47 intake all the way in the front? It takes a huge amount of space. Why not put it further to the rear top like in a P-39 or sides like P-38 oil coolers or bottom like the P-51 oil cooler? (Latter might cause debris problems?)

Offline tartle

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P-47 air cooled; P-51 liquid cooled may have some part to play in the aircraft powerplant designers' choices.
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Offline Granit

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Why not put it further to the rear top like in a P-39 or sides like P-38 oil coolers or bottom like the P-51 oil cooler?

Republic did so, making the P-72.

 
Airplanes are interesting toys but of no military value.
- Marshal Ferdinand Foch, 1911.

Offline J.A.W.

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Ah, yeah, the huge P&W R-4360 'corncob' 28 cylinder 4 row radial..

It was tried as a fighter mill & flown in both Thunderbolt  & Corsair airframes,
but it failed to offer any worthwhile performance improvement over the proven R-2800 installations.

No production Thunderbolts & ~10 Corsairs were built to examine the monstrosity.
The XP-72 shown - deleted the turbo, & flew as a single stage mechanical supercharged unit..

The R-2800 equipped P-47 utilized the ram air effect via the scoop integral to its engine cowl..

Tartle is correct to note that liquid cooled engines could operate inter/after coolers using their liquid coolant,
this of course, is a more compact/efficient method than the air/air type utilized by the R-2800..
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Offline J.A.W.

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Here is an example of a much modified Mustang racer, with intakes moved to the wing leading edge..

http://www.warbirdsnews.com/warbird-restorations/anson-johnson-p-51-racer-restored-neam.html
« Last Edit: April 24, 2014, 08:11:08 pm by J.A.W. »
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Offline J.A.W.

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This article from 'Flight' shows the Hawker Fury as fitted with Centaurus radial & Sabre inline mills..

http://www.wwiiaircraftperformance.org/Fury/Sea_Fury_Flight.pdf



&  the Hawker Fury matched with Griffon inline/offset annular radiator.

http://1000aircraftphotos.com/Contributions/PippinBill/5597L-2.jpg
« Last Edit: April 24, 2014, 09:09:19 pm by J.A.W. »
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Offline J.A.W.

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This 'Flight' article shows the comparatively compact arrangement of the R-R Griffon intercooler.

http://www.flightglobal.com/pdfarchive/view/1945/1945%20-%201853.html
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Offline tartle

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Most Typhoon websites contain the same sentence:
"Another Typhoon modification, the P.1010, was to have had leading-edge radiators and a turbo blower, but work on this was not proceeded with."
At Kew this morning whilst waiting for some documents to arrive from the vaults I found a reference to a 'turbo supercharged Typhoon Proposal"
I ordered it up (from the vaults) and to my surprise amongst all the reports and documents was a couple of folded blueprints.
The best copies I could get are attached below:
The first three show the engine layout and blower position in wing roots behind wingroot intakes'
The GA is in the next three.
Some performance estimates will follow
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Offline JFC Fuller

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Oh tartle, you really do know how to spoil us. I do love that moment at Kew when you realise the folder you have collected contains one of those envelopes that can only contain some sort of large chart or plan.

Those drawings do raise a number of questions though, most notably whose turbo were they thinking of using?

Re Sabre Furys; without doubt the best looking UK piston engined fighters ever built and probably the best performing too. However, the Air Ministry preferred Centaurus birds, even in Tempest form, so tried to chop 1,500 Sabres from the 1945 programme. The Liverpool factory was intended to be capable of, and seems to have achieved, 2,000 Sabre's a year. I don't have the figures for the original Napier Acton plant.

Offline J.A.W.

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Good archive mining effort - well rewarded there, T.

Paper proposal only? Unless it was a 'sweetener' for the mooted US production?
For Bell/Chrysler perhaps? Chrysler intended their V16 to be turbo'd, & Bell tried to turbo their P-39..

Napier has now been producing turbochargers for longer than they made aero-engines, but I don't know if they
ever actually test ran - or flew - a turbo-Sabre..

JFCF, as the Flight Fury article makes plain, the RAF was jet bent, & did not want any new piston fighters.

The Centaurus Fury was 'marinated' for the RN/FAA ( oddly- since the Griffon was the FAA mill).

& the ratio of Sabre Tempests to Centaurus Tempests built ended up being ~2-1.

Sabre Tempests were being run hard ( the way they ran best) right up to the mid `50s - as target-tugs,
- likely as a way of using up all those Sabres held in store.
« Last Edit: April 25, 2014, 04:12:38 pm by J.A.W. »
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Offline J.A.W.

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 It seems the Sabre Fury prototypes were the fastest mil-spec piston powered aircraft below ~20k ft.

Given the prodigious output figures published for the Napier Sabre..

 'Aircraft Engines of the World'- gives Sabre 7 rated output as "3,500hp/3,850rpm @ +20lb (70.6in)" for take off,
& a "military rating of 3,055hp/3,850rpm... ...normal rating of 2,235hp/3,700rpm... cruising... 1,750/3,250..."
(Figures for low - M/S - alt/levels).

 A turbo installation which would maintain that Sabre boost/power output to +30k ft, - would certainly have allowed the Hawker fighters an unequivocal 'fastest' piston-powered accolade..
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Offline JFC Fuller

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There were large scale cancellations of piston fighters for the RAF in 1945. The Air Ministry seems to have favoured the Centaurus, even for RAF aircraft, for the Pacific theatre. The reason for the final figures favouring the Sabre Tempest is because it took a long time to set up Centaurus production which pushed out Tempest II production to such a stage that it suffered heavily from the 1945 cancellations. However, it is true that all RAF Furies were to have the Sabre VII.
« Last Edit: April 25, 2014, 05:36:39 pm by JFC Fuller »

Offline J.A.W.

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 JFCF,

- it is very likely,  more a question of engine availability, & production-political-service need issues..

.. since 400 Tempest Mk I (with higher altitude rated Sabre & wing leading edge radiators) were also cancelled.

 & like-wise the final (& best performing production type) Tempest - Mk VI - was cut back to a total of 143 built.

Addit: A quick book-check shows a bit of production-political musical chairs-type mucking about too..

Gloster were to build Tempest Mk II ( Centaurus), but were busy with Typhoon-then-Meteor, so Bristol
were assigned the Mk II production, but Hawker then finished with Hurricane production..

.. ( & Hawker workers on strike upset Tempest production in 1944 - when they were required for defence against the V1 cruise-missiles).. , so Hawker then got all Tempest/Fury production back 'in house' at Langley.
« Last Edit: April 25, 2014, 06:36:31 pm by J.A.W. »
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Offline JFC Fuller

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The Tempest I was cancelled because Napier abandoned the Sabre IV due to development issues. As far as I am aware this was a case of either or, not of additional engines/aircraft as there was not a planned increase in Sabre output. Those 400 aircraft became Tempest Vs.

For the record, Ministry of Aircraft Production preferred the Sabre- because the two plants associated with it were up and running at full tilt. It was the Air Ministry that wanted the Centaurus.

Offline tartle

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JFCF... the turbo was specified as a General Electric one....
and then this morning we unearthed this installation drawing of the Fairey P.24 plus a good description.. to long to post will absorb and summarise ... eventually.
Then there was that matter of the A.S.H. gas turbine... see the other thread.
...tbc
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The Tempest I was cancelled because Napier abandoned the Sabre IV due to development issues. As far as I am aware this was a case of either or, not of additional engines/aircraft as there was not a planned increase in Sabre output. Those 400 aircraft became Tempest Vs.

For the record, Ministry of Aircraft Production preferred the Sabre- because the two plants associated with it were up and running at full tilt. It was the Air Ministry that wanted the Centaurus.


JFCF,
Do you know if the Air Ministry wanting the Centaurus  - for the Tempest  - was related to the fact
that the Tempest design was amenable to accommodation  of the Bristol mill, whereas the Typhoon,
(then in full production/operational service/attrition) was limited to Sabre use only?

How many Centaurus mills did Bristol actually get in to WW2 wartime combat service - in any airframe?

Is it known why the FAA, went with the Centaurus, even though the likes of Firefly & Seafire were
using the Griffon, as intended?

Was it due to the Fury prototypes running the Griffon not performing so well?
Or was there a contra-deal with R-R & Griffons going to the Shackleton instead?

The whys & wherefores of the British aero-engine market share/operational use are curiously complex..


Addit: Are the numbers of the 'big three' British piston aero-engines produced definitively known?

AFAIR, numbers built  Griffon  ~8,500,  Sabre ~6,000 &  Centaurus ~2,500 (Centaurus figures, from-Wikipedia).
« Last Edit: April 26, 2014, 10:34:01 pm by J.A.W. »
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Offline tartle

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I seem to remember from my reading of 'Devons' that part of the problem with wartime planning was the sheer volume of aero engines needed and the obvious inability to switch from one engine to another without considerable disruption. The development delays with say the Sabre represented a nightmare for the planners as it would mean an idle factory... the beauty of the power 'egg' developed by RR and Bristol meant that it was easier to substitute a RR powerplant for a Bristol one and vice versa. Hence the big bomber programme that utilised the opportunity. Must have another look when I finally escape Kew's magnetic attraction.
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Offline J.A.W.

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This site includes an interesting photo of a group of female inspectors examining a laid out Sabre on a table..

http://www.aviationshoppe.com/sabre-ii-sleeve-valve-engine-p-256.html

The accompanying blurb appears to be lifted wholesale from Len Setright's work..
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Setright's work is great, but in a previous three we tried tracing down the really high HP Sabre test runs and nobody could work where he had gotten the numbers from: http://www.secretprojects.co.uk/forum/index.php/topic,11807.msg114525.html#msg114525 
« Last Edit: April 27, 2014, 03:02:51 am by JFC Fuller »

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Returning to the P-72 intake discussion. The liquid vs air coolant for engine allows for different design solutions:
As water or glycol/water is denser than air in terms of bulk and specific heat it allows minimum loss ducts to be schemed e.g. Mustang and Sptifire. However with air cooled cylinders options are less... the sooner the air gets to the cylinder the better from a ducting point of view. The P-72 minimised the air inlet size round the prop spinner by using a fan. The mechanically driven supercharger was located rearwards of the engine and driven by a long shaft as a search of our site would show. The engine charge air can then go in the belly intake into s'charger then into engine- swapping a short duct for a whippy shaft seems like a swapping one issue for another! You can draw anything on paper as I am finding as I dig deep into  archives... but does the system work in practice?
« Last Edit: April 27, 2014, 10:54:03 am by tartle »
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Offline J.A.W.

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AFAIR, Len Setright claimed (when challenged over the Sabre power outputs included in 'The Power to Fly'),
that he had both interviewed the engineers & had seen the documentation that verified  them..

Perhaps there is some gold (Sabre dyno-tests) that remains hidden in the vaults at Kew?


The US remote mount, shaft-driven 'auxiliary' superchargers as fitted to the P-63 & XP-72 (proposed, but not flown on the latter) were a bit of a 'lash-up' arrangement for USAAF (nominally turbo users for hi-alt function)
use, but the USN had the most sophisticated mechanical supercharging arrangements for radials.
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Offline J.A.W.

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Setright's work is great, but in a previous three we tried tracing down the really high HP Sabre test runs and nobody could work where he had gotten the numbers from: http://www.secretprojects.co.uk/forum/index.php/topic,11807.msg114525.html#msg114525



There appears to be some confusion in this linked statement too, since 3,500hp was listed as the rated
take-off power for the Sabre 7, - in 'Aircraft Engines of the World' - rather than as a destruction test..

The documents would of course, set the matter straight, when/if located/posted..
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Offline JFC Fuller

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Every other source I have ever seen for the Sabre VII gives it 3,050hp and not 3,500hp, so I have always disregarded the latter figure as incorrect.

Tartle,

I think your big bomber programme was B.1/39 which was intended to have interchangeable Hercules/Griffon power eggs. Hercules / Griffon matching in paper designs was all the rage for a period in 1939-41. Also, don't forget the Tornado / Tempest approach of using the same basic airframe with different power-plants which of course paid dividends in that case. 

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JFCF,
'Aircraft Engines of the World' lists the Sabre 7 output ratings on +17.25lbs & +20lbs boost.
The 3,500hp take off rating is at the higher boost level.

The Tornado could accommodate the Centaurus in place of the Vulture, but the Typhoon suited the Sabre only.
Likewise the Manchester was proposed as a twin - to use Vulture/Centaurus, but neither was readily
operationally serviceable/available, so the Lancaster adopted quad Merlins/Hercules instead.

The Bristol Hercules & R-R Merlin 'power-egg' units were used on service Beaufighter & Lancaster aircraft,
& the Mosquito trialled the Merlin 'P-E' type against the regular De Havilland installation.

The Halifax also used both Hercules & Merlin, but AFAIR, not the 'power-egg' per se..
« Last Edit: April 28, 2014, 04:15:47 am by J.A.W. »
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Offline JFC Fuller

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Napier only ever ever advertised the Type as a 3,050hp engine. If 3,500 was achieved on a bench (which it probably was as that SHP was offered for an evolved version beyond the VII) it was not an operational engine rating.

Typhoon and Tornado used the same basic wing and rear fuselage, it was the fat Vulture that caused the forward fuselage/engine mounting changes.

Manchester was not merely proposed as a twin but entered service as one, however the Vulture lacked both the power and reliability required for operational use- hence Halifax and Lancaster coming to fulfil the B.12/36 role. The Lancaster Power egg was the Merlin XX Ready to Fly Unit (at least in propaganda).

Offline J.A.W.

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See here for Napier Sabre specs & outputs..

http://www.wwiiaircraftperformance.org/Aircraft_Engines_of_the_World_Napier_Sabre.pdf

Note: the steady increase in boost & power ratings over series development, up to +20lbs/3500hp for T-O.


Manchester was dismal in service , & Halifax, while also proposed as a twin - only saw service as a 4..

Warwick also saw service as powered by a brace of R-2800s (or Centaurus), but was little liked/used..
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BMW also offered its WW2 radial as a 'power-egg' for Do 217 & Ju 88/188 twins plus some 4/6 (Ju 290/390) use.
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Important factor to note with fighter engine functionality was the careful attention to ease of operation
 paid to controls in German & British applications, such as the BMW Kommando-gerat,
& as listed in the Sabre 7 specs, an equivalent single lever cockpit control set-up..

"Master control uniting throttle, boost, injector, ignition & propeller controls."
& the ADI likewise incorporating automatic ignition & fuel injection over-ride control.

US fighter engine installations tended to keep their pilots much more busy with fettling these factors in flight.
« Last Edit: April 28, 2014, 06:11:56 pm by J.A.W. »
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A quick squiz at the 'pilots notes' for the Tempest reveals a significant difference in listed Vne speed for the
Centaurus powered Mk II (480mph below 10k ft) & the Sabre powered Mk V (540mph @ same height).

I presume this may have something do with the Sabre being much more tolerant of high rpm..
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Offline J.A.W.

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Here, a 'Flight' article gives Sabre 7 performance - charted at up to +17.25lb boost..
& also lists 4,050rpm @ max boost - as allowable for Vne dives.

http://www.flightglobal.com/pdfarchive/view/1945/1945%20-%202284.html

Elsewhere Flight acknowledges "nearly 4,000hp on test" for the Sabre,
Fairly pushing the limits of propeller capacity in 1945?
« Last Edit: April 28, 2014, 08:11:53 pm by J.A.W. »
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Offline tartle

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My data says 3,350 hp. for the VIII and 3,055 for the VII...I may get to Kew next weekend ... ??? !!!
As to props absorbing power... the VIII was a contra prop design.
A good omen was being passed by a lorry carrying 'TeaCrates" last time I was there.
« Last Edit: April 29, 2014, 02:01:20 pm by tartle »
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Ok T, so..
'Aircraft Engines of the World' gives a Sabre 7 take-off rating of 3,500hp at +20lbs boost..
..how do these published figures compare with your data?

Sabre power ratings were revised with increased boost levels, +7, +9,+11,+13,+15, +17.25 & +20lbs.

AFAIR, S. Camm was reportedly irritated by Rotol propellers being unavailable, when De Havilland units
were proving unequal to the task of handling the Sabre - running on increasing boost - for V1 interception..

Kiwi Tempest pilot ( & successful 'rat-catcher' against the Me 262) Ron Dennis commented..

"All our machines were fitted with Rotol airscrews when the maximum rpm were increased to 3,850
from 3,700 & boost to +13lbs from +11, as the De Havilland airscrew could not absorb the added power
& more than once shed a blade, with somewhat detrimental effects..."

& T, - Good hunting @ Kew..
« Last Edit: April 29, 2014, 05:29:08 pm by J.A.W. »
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Offline J.A.W.

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From Bill Sweetman's 'High Speed Flight' - re Sabre power..

"Cooling & supercharging were the limits to performance, & when these limits were absent,
in bench runs, the Sabre produced phenomenal amounts of power, easily generating 3,750hp
& capable of being pushed to even higher outputs."

B.S. will maybe have a data set that verifies this assertion?

Or was he simply reiterating Len Setright's stuff?

« Last Edit: April 30, 2014, 03:21:54 am by J.A.W. »
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Offline tartle

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Being published by Janes gives Sweetman's book a higher authenticity rating but in the last months of researching my own book I have found that even the best accept what seems fact and turns out to be just wrong... as documents are relaesed at Kew they enable re-interpretation from the doc rather than memory!!
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Quite right too, T, & verification via the mother lode of original documents must - of course - take precedence..

Anyhow - here is a bit about the Soviet approach by contrast..

http://mig3.sovietwarplanes.com/mig3/engineam35a.html




« Last Edit: April 30, 2014, 03:32:04 am by J.A.W. »
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In this following link, Len Setright states re: Sabre power figures..

"My information came from the wartime R&D department of Napier..."

http://www.hawkertempest.se/index.php/contributions/stories/130-the-greatest-engines-of-all-time-by-ljk-setright

« Last Edit: April 30, 2014, 07:48:41 pm by J.A.W. »
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Offline JFC Fuller

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Great, in which case there will be a paper trail somewhere, strange that the Napier Heritage Trust has no record of it and Setright appears to be the only author to have discovered this though.

The Sabre was a great engine, arguably the best design to see service in WW2 from some perspectives. However, the hero worship, and corresponding emotional conspiracy theories about why so few (comparatively speaking) were made, borders on TSR-2 levels of absurdity. The reality is that Napier didn't have the technology to manufacture the engine (it needed Bristol tech), it couldn't make a high altitude configuration and EE ultimately had to be brought in to provide proper management. Even then, it wasn't until 1945 that production and maintenance converged to end the engine supply problems.

Offline LowObservable

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The source was LJKS. Probably just as well that the 3750 hp had a caveat pinned to it about bench runs. However, operational Sabre performance (particularly relative to capacity and frontal area) was indicated by the Tempest's large low-level speed margin over almost anything else - hence its use for Diver and rat-catching. Clostermann reports that escort Spitfires could not keep up with bomb-laden Tempests, even loafing along at moderate boost, and that the only prop that beat him for speed was a Do335.

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Indeed, it was an immensely powerful engine, and one suspects that the Sabre VII powered Fury would have easily beaten that Do335 and that the Tempest VI (with it's 2,340hp Sabre V) would have given it a run for its money.
« Last Edit: May 01, 2014, 05:36:54 am by JFC Fuller »

Offline J.A.W.

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Great, in which case there will be a paper trail somewhere, strange that the Napier Heritage Trust has no record of it and Setright appears to be the only author to have discovered this though.

The Sabre was a great engine, arguably the best design to see service in WW2 from some perspectives. However, the hero worship, and corresponding emotional conspiracy theories about why so few (comparatively speaking) were made, borders on TSR-2 levels of absurdity. The reality is that Napier didn't have the technology to manufacture the engine (it needed Bristol tech), it couldn't make a high altitude configuration and EE ultimately had to be brought in to provide proper management. Even then, it wasn't until 1945 that production and maintenance converged to end the engine supply problems.



Indeed, the emotive outpourings, from excoriatingly condemnatory to hagiographic - per the Sabre,
are likely worthy of some kind of psycho-sociological thesis in themselves..

However, given the arcane, if not outright Dickensian, state of affairs in the British aero-engine scene,
both at Napier-Acton & the A.M./M.A.P. it is without doubt, a fabulous achievement that the Sabre,
(alone of the much hyped 'Hyper'-type mills) - actually did something practicable at all..

The missing official Napier works Sabre dyno-data, if/when located - will be icing on the 'piece of cake'.

The Do 335 is far more mythical than the Tempest/Fury, since the former did not actually get to do anything..
..in LW or post-war Allied hands, - other than some hasty & furtive test flights..

P. Clostermann writes a good read, but his story about a Do 335/Tempest encounter must be,
ah,  tempered,  by the fact that the RAF 2nd TAF Tempests did - in fact - bag every kind of operational
Nazi 'long-nose' prop & turbo-jet type to be had..

& Does anyone know how to access the guncam footage of such encounters..
.. Clostermann claimed to have taken some of the Do 335, & it would have been of interest..

Further, Clostermann admits he only "toyed" with 'going through the gate' - in pursuit of the Dornier,
- whereas he does describe actually doing so later, (albeit - in a new Rotol propeller equipped Tempest)
  as..

" The effect was extraordinary & immediate.
 The aircraft literally bounded forward with a roar like a furnace under pressure...
...I simultaneously caught up my quarry, & left my pursuers standing."



« Last Edit: May 01, 2014, 06:41:56 pm by J.A.W. »
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Interesting that the 'Pilots Notes' for the Tempest V ( early Sabre IIA powered variant) allow for
the Sabre's output at a "1 hour limit" of the "climbing power" setting at "+7lbs boost @ 3,700rpm"..

This power setting (@ 190 gph) would expend the internal fuel capacity of the Tempest (160gal),
 - in less than an hour..
« Last Edit: May 01, 2014, 08:23:00 pm by J.A.W. »
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Offline J.A.W.

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& early unreliability notwithstanding (cause of ~20% of Typhoon losses in 1st year of service) the Sabre powered
Typhoon did provide the RAF with a 4 cannon, 400+mph Vmax & 525mph Vne interceptor that could catch & destroy the FW 190 JABOs attacking Britain - & of course it was also capable of effectively delivering a fair bit of offensive external ordnance - in the fighter-bomber role.

It took a redesign of the wing & addition of a late series Griffon for the 20 series Spitfires to carry the 4 cannon fit & be cleared for a 525mph Vne, as standard - years later than the Typhoon..

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Offline JFC Fuller

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& early unreliability notwithstanding (cause of ~20% of Typhoon losses in 1st year of service) the Sabre powered
Typhoon did provide the RAF with a 4 cannon, 400+mph Vmax & 525mph Vne interceptor that could catch & destroy the FW 190 JABOs attacking Britain - & of course it was also capable of effectively delivering a fair bit of offensive external ordnance - in the fighter-bomber role.

It took a redesign of the wing & addition of a late series Griffon for the 20 series Spitfires to carry the 4 cannon fit & be cleared for a 525mph Vne, as standard - years later than the Typhoon..

Absolutely, just a shame about that fat wing (solved by the Tempest) and the Sabres poor altitude performance.

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Yeah, too bad Hives didn't send Stanley Hooker down to sort out the Sabre supercharging..(as if!).

The Tempest I/Sabre IV had unrealised wartime potential - back in `43..

From Mason's 'The British Fighter Since 1912',

"When Bill Humble carried out the initial performance checks with HM 599... he recorded a maximum
speed of 460 mph TAS at 24,000ft & , after fitting a thinner tailplane, this was increased to 472mph..."

Mind you, Mason reports the later Sabres could get things fairly moving even in the denser air below 20k ft.

Per Tempest F6..

 "The original Tempest V prototype, HM 595, was modified to Mk VI standard & 1st flown
by Humble in this form on 9 May 1944...
Performance trials at Boscombe Down revealed a maximum speed of 462mph at 19,800ft..."
« Last Edit: May 02, 2014, 05:33:20 pm by J.A.W. »
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 'Aircraft Engines of the World'..
.. gives (Tempest F6 equipped) Sabre 5A - take-off rating as 2,565hp/3850rpm @ +15lbs boost.

AFAIR, the increased boost settings of +17.25/+20lbs were accorded to the Sabre 7 - with ADI..
« Last Edit: May 03, 2014, 03:14:19 am by J.A.W. »
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Sabre IV consistently failed it's type tests (three times IIRC) which is why the Tempest I orders were converted to Tempest VI orders.

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Sabre IV consistently failed it's type tests (three times IIRC) which is why the Tempest I orders were converted to Tempest VI orders.


JFCF,
-Do  you know what the mechanical failure point of the Sabre IV on type-test was?
Could it have been due to high altitude supercharger set-up?

Or was this a pretext - for stopping development of a high altitude capable Sabre?

Mason writes..

"The first production Tempest V, JN 729, was flown by Humble on 21 June 1943 ( by which time
 the prototype had been flown with a Sabre IV with chin radiator & had achieved a speed of 459mph
at 24,900 feet, fully loaded)."

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According to Mason,
- the cancelled order for 400 Tempest I was replaced by orders for Tempest V, with production delays
due to the change from radiator fitment in wing leading edge to fuel tank instead.

The Tempest VI production order of 300 was reduced to 142 - as built, by the end of the war/need.

Mason also remarks re the Centaurus powered Mk II;

"This proposal had been made by Camm's staff as a result of experience being gained in 1942 with the
Centaurus Tornado, rather than for any liking of radial engines in fighters by the great designer himself..."
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R. Beamont flew the Tempest as both Hawker test pilot & RAF combat wing leader.

& he appears to concur with S. Camm, in not really liking the Centaurus powered Tempest Mk II,
(From - 'Test Pilot')

"...the large radial cowling restricted the view...caused a noticeable reduction in directional damping
in all flight conditions...its handling was never up to the crisp, taut directional standard of the Mk V."
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Air Ministry didn't get the memo, they ordered 2,130 in total- I have never seen final order numbers for the Tempest V but Tempest II orders certainly exceed, a substantial number, the production of Sabre Tempests.

Sabre VIII, 25lb boost for 3,350hp.

Offline J.A.W.

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Which would also mean that Mk II cancellations would also exceed the number of Sabre Tempests built.

JFCF, have you a reference link for a Sabre 8 running the +25lb boost/3,350hp rating?

Was it a bomber ( Warwick) installation without an effective high speed ram intake?
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Offline JFC Fuller

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Centaurus Tempest cancellations were because of the end of the war and no reflection on the Tempest II as an aircraft.

3,350 hp Sabre VIII (E.122) is from "By Precision into Power" by Alan Vessey. Based on this Flight page: https://www.flightglobal.com/pdfarchive/view/1946/1946%20-%201443.html

It seems like it was a fighter installation though I would caution that the same flight article also mentions 3,500hp and in another article from many years later mentions 4,000hp but also states it was intended for the Fury- though I have seen other reference anywhere to such an installation.

The Napier Heritage Trust states that the Sabre never got over 3,500 hp before breaking up and that Setrights numbers are incorrect.
« Last Edit: May 04, 2014, 04:18:00 pm by JFC Fuller »

Offline J.A.W.

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Thanks for that JFCF, I note that the Sabres were a bit much for the poor ol' Warwick..
Power enough to push Vmax to Vne limits, & exhaust thrust to blast & burn the fabric off too..

Obviously the war's end/major aircraft cancellations included Tempests, Centaurus & Sabre alike,
but were sufficient Centaurus engines even available in 1945?

~1500 Centaurus engined Hawker Tempest/Fury were eventually built, but that was over a number of years..

I recall reading that Neville Duke, when Hawker works test pilot post war - regarded flying the most highly developed Sabre in VP 207, the 2nd Sabre Fury, as offering a fairly thrilling ride for a piston job..

A real pity it wasn't kept for posterity, along with the MB 5 & even a Spiteful/Hornet too.

Perhaps Kermit Weeks would be best to flight test his Sabres in a Fury airframe before risking the very rare Tempest V he has ( he's had it undergoing slow rebuild to flight status for a couple of decades) straight off.

Given that 'Aircraft Engines of the World' quotes specific figures for Sabre 7 ratings at various power settings
& altitudes, ( & including 3,500hp @ +20lbs for take-off), I would take that as more credible than some hearsay type of anecdote, sans evidence..

I also note that the Napier adverts in 'Flight' state -  "3,000hp plus" - for the Sabre..
« Last Edit: May 04, 2014, 05:05:51 pm by J.A.W. »
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Offline JFC Fuller

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In the absence of evidence to the contrary Setirights figures should be taken with extreme caution simply due to the complete lack of consistency they have with any other published figures not to mention their outright dismissal by the Chairman of the Napier Heritage Trust, hardly hearsay. 3,000+ is classic marketing, the number was 3,050hp.

Centaurus production was ramping up rapidly late in the war with both the underground Coresham factory and the Accrington factory being turned over in large part to the type; Centaurus orders were made on the basis of Tempest II orders. 

Offline J.A.W.

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How many Centaurus engines were available prior to war's end?

Not enough for a combat unit to use..
Certainly the Mk II prototypes ran a fair few iterations on test..

& since the 'Aircraft Engines of the World' figures for Sabre 7 outputs at +17.25lb boost are kosher,
being confirmed by the 'Flight' article - by what valid reason do you doubt the 3,500hp @+20lbs boost
outputs listed?

Has the 'chairman' interviewed the Napier test engineers? Or seen the test data?
Len Setright stated he had, is his ( or Bill Sweetman's) credibility that questionable?

& "3,000hp plus" - could well include 3,750hp..

Certainly the test data if/when found - will  speak for itself..
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Offline J.A.W.

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Indeed, the 3,750hp figure for the Sabre on bench test noted by Setright & Sweetman is easily feasible,
-given the posted Sabre 7 in-flight rating of 3,500hp, & the bench test figure of 3,800hp for the P&W R-2800..
& - on probability I'd be more likely to dismiss the prognostications of the 'chairman'..

Note that the competitively current Reno race Merlins are also making around that power too..

So it would appear that even Len Setright's claim for the Sabre to have produced 5,000+hp..
 
..at equivalent boost levels.. as are run by the racing Merlins at Reno..

.. to be well within the bounds of mechanical probability..

Step up that rich enthusiast.. & what's that 'Virgin' chap R. Branson.. doing these days..
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Offline JFC Fuller

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Sweetman's figures came from Setright- see post 158. Setright is the only source to offer such high figures and they are directly contradicted by the NPHT. I actually don't doubt 3,500hp figure but I suspect thats where the engine tore itself apart not he bench, it seems telling to me that the Napier hypothetical 500hp fighter was only given as having 3,350hp.

The 5,000hp figures claimed by Setright are, according to my notes, based 45lb boost which seems absurdly high. Even the notorious Merlin RM.17.SM was only taken up to 36lb max and spent most of its tests at 30lbs.

I can not see 4,050rpm in any of the links you have provided, could you point me in the right direction? The Flight Sabre VII article of November 1945 gives a maximum output of 3,050hp at just over 2,000 ft with 3,850 rpm and that seems consistent across the flight archive.

In 1945 Centarus production was rapidly ramping up and orders for both Tempest IIs and the required engines were in place.
« Last Edit: May 05, 2014, 04:14:03 am by JFC Fuller »

Offline J.A.W.

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Centaurus production was very late.
For an engine that was apparently running in 1938 to miss WW2..

Sweetman -himself- wrote post#158?
If so, I guess it follows that he accepted Setright as accurately presenting the factory data..

As repeated several times, the 'chairman' is plainly wrong, since the specialist book 'A-E-o-t-W'
 clearly lists the factory figures for Sabre 7 flight ratings, inc' 3,500hp for take off @ +20lbs boost..

The 4050rpm Sabre dive allowance is listed in the Flight article (p.552) data tables for Sabre 7 @ +17.25lbs..

Boost levels in engine dyno-room test cells are effectively unlimited, except by the mechanical strength of the
machinery.. & it would be self evident that Napier would have no shortage of expendable test engines.

The Reno race Merlins do indeed - run those boost/power levels in flight, albeit they have had decades of
racing development & run Allison con-rods ( notorious R-R design weak point) to hack it..

Given the known power output progression at increasing boost levels, there is no reason to doubt that
the Sabre could not do likewise - in proportion - to demonstrate exactly what Setright wrote..
« Last Edit: May 05, 2014, 03:00:11 pm by J.A.W. »
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Offline JFC Fuller

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I learnt long ago that specialist does not mean correct. I still think a Sabre made 3,500hp but I suspect the chairman of the NPHT is right that it probably broke up about there- the strengthening required to take it up to 45lb boost would have been very substantial indeed (there had already been strengthening to produce the VII) and Napier's own wonder fighter paper designs were accredited only with 3,350hp.

The biggest problem with the Centaurus seems to have been the Hercules being in its way.
« Last Edit: May 05, 2014, 05:06:46 pm by JFC Fuller »

Offline J.A.W.

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& the Hercules certainly took some time to reach its development potential in production form too..
Centaurus being more complicated & heavier,with its valve gear drives mounted fore & aft of crankshaft.

As for how expressions of vague plans/mooted ideas (sans direct references) in 'Flight' articles,
 - or the unverified pontifications of a 'chairman'..

.. compare to extant published detailed data sets  (& obviously factory sourced figures)..

- in either 'Flight', or in a dedicated reference book 'A-E-o-t-W'..
 ..well, it is quite plain which holds water validity-wise..

& in the current absence of a running/flying/development Sabre..

..the 'holy grail' of course, will continue to be the 'missing/lost' Napier factory Sabre data sets.

Len Setright wrote 'Power to Fly' over 40 years ago,& stated having direct access..

.. are there any Napier Engineers with 'hands on' experimental Sabre experience  still living?

& If so - then why hasn't  the 'chairman' put their 1st hand recollections - on record?
« Last Edit: May 05, 2014, 05:57:49 pm by J.A.W. »
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Offline JFC Fuller

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Both AEotW and the NPHT are secondary sources, neither has a particular validity advantage. Setrights claims are quite fantastical given the era.

I would say that Hercules didn't reach its potential until post war.

Offline J.A.W.

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Well, in the absence of actual Napier & Sons/E.E. letterhead factory data sheets/charts..

Seriously though, the data listed in 'Flight' - where they feature the Napier works must be fairly straight..
..since they were obviously provided with it, by N/EE for the article..

& 'A-E-o-f-t-W' clearly lists identical data, but goes further, development-wise,- since it is of a later date,
- so to any reasonable thinking chap must be the best available data set, & certainly better than hearsay..

What some may consider 'fantastical' - Len Setright wasn't actually known for outright bullshitting, was he?

In fact extrapolation of in-flight performance tests done at Boscombe Down as were based on the same airframes/altitudes - ought to be a fairly reliable way of gleaning power outputs..

Sabre Tempest sea-level performance rose from 376mph @ +7lbs boost - to 418mph @ +17.25lbs boost..
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Offline Nick Sumner

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Napier Heritage Trust

www.npht.org

Has extensive archives, but a lot of it is unsorted and waiting for volunteers to catalogue.

Offline JFC Fuller

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Nobody is accusing Setright of "bullshitting", there are any number of reasons his numbers could have been inaccurate.

Offline J.A.W.

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Len Setright stated that he had obtained the figures in 'Power to Fly' from source, "...Napier R&D"
If he has been shown to be prone to use 'inaccurate' data, or worse - run stuff he just made up,
- does anyone have actual examples?

Otherwise, & given the evidence from material provided so far, there is the Sabre - flight rated @ 3,500hp..
As well as "easily capable" of significantly more on ground test, just as the R-2800 was dyno tested at 3,800hp,
- 1,000hp more than it was rated for flight..
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Offline JFC Fuller

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I repeat, nobody is accusing of Setright of making anything up.

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Here, a fairly scathing U.S. report on Kawasaki's attempts to licence build a decent DB 601/5 series mill..

http://www.wwiiaircraftperformance.org/japen/ATIG-Report-39.pdf

Goes to show - producing efficaciously functional aero-engines aint generally amenable to easy outcomes..
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Offline JFC Fuller

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To return briefly to the Turbo-blown Typhoon, and to the high altitude Kestrel also discussed earlier, I am left wondering what happened to all the RAE turbo work? Bristols used GEC units for the small number of high altitude Hercules they built, as does the Typhoon proposal. Only RR seems to have developed credible high altitude piston engines for use during the war. RAE work seems to have stopped about 1927 when James Ellor left for RR- perhaps that explains the turbo Kestrel? Did UK manufacturers ever attempt their own turbos, or was their a policy decision?

Offline tartle

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JFCF,
I have been slowly putting the pieces of the supercharger story jigsaw together; all the turbo experience the UK seems to have had is sad whilst the mechanically driven work at RR is more positive plus aircraft policy and Meredith's work made the mechanical a better short-term bet than the turbo;
the turbo work at RAE did not stop butlater some of it began to look suspiciously like a gas turbine! There were three Air Min sponsored paths.. Frazer and Chalmers, Brown-Boveri and in-house; Bristol kept a watching brief on F&C, Rolls on B-B, and RAE on all of them. Much more to be said when documents are read rather than scanned!
One thing that puzzled me was where Napier's got their supercharger expertise from when they moved on from turbos designed for the Lion by RAE and did their own designs for the Schneider engines. These were designed by Penn who came from the RAE and I think was in the team originally under J. Ellor.
There is a precedent for believing that Setright's figures couId reflect a run on the test bed and that is the reverse case of the Griffon I out of the 'R' engine. We know that the 'R' passed a one-hour type test for the 1931 races and then a derated version known as the Griffon I was built, probably at around 1500 hp. about a thousand down on the short-life version. All we need to do is find the document!! So far the first files I have searched at Kew do not throw any light on the matter... there are other files to be looked at on another trip!.

"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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The British seemed justifiably unconvinced re turbo use, esp' for fighters,
- where the power compensation at altitude did not give enough advantage over the costly bulk & complexity..

Fighters like-wise gained most from high speed exhaust jet-thrust, to which the turbo could not offer a like push.

However, it does seem that some kind of 'arrangement' was done whereby high altitude interception/recce
would be handled by R-R Merlin/Griffon in Mosquitos/Spitfires & low altitude/ground attack would be the
job of the big Hawkers powered by Centaurus/Sabre..

Certainly there was irony in the expensive high altitude specified turbo'd P-38 & P-47 being ousted from
escort of turbo-powered B-17 & B-24 bombers by the Merlin Mustang, & relegated to low level roles..
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Offline J.A.W.

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This link, though in German - gives interesting photo/diagram illustrations of the ADI (C3 & MW-50) & grouped exhaust thrust arrangements as employed on the BMW radial powered FW 190..

http://www.deutscheluftwaffe.de/archiv/Dokumente/ABC/m/Motoren/BMW/Leistungssteigerung/BMW%20801%20D%20Leistungssteigerung.html
« Last Edit: May 07, 2014, 09:20:46 pm by J.A.W. »
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Offline J.A.W.

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& from a mid `30s 'Flight' article - a French Farman 2-stage supercharger schematic..

http://www.flightglobal.com/pdfarchive/view/1935/1935%20-%201022.html
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Offline tartle

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Rolls- tried to design a two-speed supercharger drive in the same overall engine dimensions as the single-stage drive; they had major reliability problems and so with a war coming took a Farman licence... this made the engine 6" longer and though the Hurricane could take the forward CofG move the Spitfire could not so a major tear up was schemed (Spitfire III). Priorities in the air led to the Hurricane II with Merlin two-speed single-stage s'charger and the interim Spitfire V which had the Merlin 45- the central inlet supercharger of the XX but no two-speed drive so with the cabureter mounted around the other way round had same length as the existing Spifire engine.. low altitude, etc were accommodated in the short term by a larger impeller (for high up) and cropped (foe low altitudes). RR Hucknall did the first Spitfire V conversions whilst Supermarine geared up for mass production. The flexible structure I mentioned today when talking Sabre is seen in action here. Incidently the Farman supercharger was awful aerodynamically and there was talk of RR help in exchange for the licence but the war soon put paid to that idea... and Turbomeca were doing good things anyway.
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Offline J.A.W.

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T, didn't R-R propose French production of a metric Merlin?

Easier mooted than done, & the effort the Russians put into French designs likewise..
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Offline tartle

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The French government were in process of negotiating a licence for the Merlin when they were over-run. French Ford company (Fordair in Bordeaux) were to be involved. Negotiations were under way in 1939 but dragged on due to Fordair's lack of concentration. Whether they would have gone as far as metrication I am doubtful as UK would be looking for components for UK engines. Willis and Buxton from RR went and spent time at Fordair and came to the conclusion they did not know how to initiate a project (e.g. building an engine as the Americans had set up things for them to operate rather than teach them to do it themselves). A Dewoitine 520 flew with a Merlin which improved its performance but Germans arrived and that line of dev was cut-off... see elsewhere in forum.
« Last Edit: May 08, 2014, 04:57:11 pm by tartle »
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Offline J.A.W.

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Thanks for that T,

& from 'Flight' - an article featuring the R-R H-24 Eagle, - this page shows the supercharger layout..

http://www.flightglobal.com/pdfarchive/view/1947/1947%20-%200629.html
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Offline J.A.W.

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I suspect ol' Frank Halford would've had a wry grin when reading that R-R Eagle Flight article..

Not only no mention of near plagiarism... but then..

Looking at both crankshafts counter rotating with output through a single spur gear..
- & the horror of simultaneous firing.. no wonder the lump was both over-weight & a harmonics nightmare..

Sabre runs its crankshafts in single rotation, but phased 180`apart for firing &  geared together via an "elegant"
-  per L.J.K.S. -  balanced compound output drive..

Like-wise in the Sabre the various drives that were subject to harmonic & shock loadings such as valve gear/ignition, were protected by the give of torsion shaft/sleeves..

The good Major H likely grinned again when seeing that R-R had also resorted to the crankshaft counterweight dampers he'd applied to his hoary old D-H Gypsy mills.. ..Sabre proved so well balanced they even deleted its needless crankshaft counterweights in its later iterations..
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Offline J.A.W.

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This 'Flight' article on the Hercules includes Roy Fedden's list of advantageous sleeve-valve attributes..

http://www.flightglobal.com/pdfarchive/view/1941/1941%20-%202830.html
 
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Offline J.A.W.

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I had remarked on the thirst of the P&W R-2800 (275 gal/hr) when running high power settings..

But the R-R Eagle 22 has it beat there.. it could get through 350 gal/hr!
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Offline tartle

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I would have thought sfc was a better comparator than gal/hr?
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Offline J.A.W.

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True T, but R-R  - oddly enough - didn't include it in the data spec set provided for the 'Flight' article..

& even a fat & fully fuelled Thunderbolt could blow all its juice in under an hour - if Eagle powered..
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Offline J.A.W.

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US fighter pilots operating R-2800s were kept busy with flight engineer-type duties..
.. by comparison to FW 190 fliers who had the benefit of the 'Kommandogerat' control automation..

Below - a NACA report appraising the device.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930093290.pdf
« Last Edit: May 12, 2014, 12:50:36 am by J.A.W. »
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Offline tartle

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Thinking about fuel consumption as yer do brought back memories of Tizard's 'sprint fighter' able to get up and intercept the Germans before they got to London... a tall order in 1935!
The Crecy came about from that thought piece.
Also looking through the RRHT Crecy book I came across the picture of Napier E.113 a twin cylinder 2-stroke sleeve valve test unit with a junk head. This soon gave trouble with sleeve sealing and supported Rolls move to an open ended sleeve design which the Ministry up to that time had been against, favouring the Junk Head.
The results of E.113 were incorporated into an X-config 24 cyl engine project, cancelled in 1942 as Sabre problems overwhelmed the Napier engineers.
An X-config is not listed in the back of 'By Precision into Power' although E.123 is mentioned as a 4,000hp 2-stroke PI petrol high speed engine. So the Napier X config remains a mystery.
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Offline J.A.W.

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Well T, maybe they ran the idea of an X-mill past Frank Halford & he told them not to be so bloody silly..

Are there any examples - anywhere - of a successful service X-type  engine?

The engine boys over at D-B turned to a bit of  a capacity bump, high comp & fat camming..
.. on their smaller ( but still ~Griffon/Sabre sized) V 12  to get cruise economy & cope with single stage
supercharger/modest boost limitations ( later going to chemical supercharging & ADI too)..

http://www.enginehistory.org/German/daimler-benz.shtml

(Scroll down the linked page for cam data comparisons)..
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Offline tartle

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Haven't got time to find which post but somewhere on the site is a growth curve for Merlin and DB engines... off to catch a train south... don't think I'll have time for Kew this time...
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Offline J.A.W.

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& here, a 'Flight' article that provides a mid war period - historical overview of supercharging..

.. inc' mention of the RAE developed Napier Lion-turbo that made 32,000ft - a couple of decades previous..

http://www.flightglobal.com/pdfarchive/view/1943/1943%20-%202320.html
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Offline tartle

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Yes the RAfactory/RAE started work in 1915 on superchargers under James Ellor; and work continued for the rest of the piston era. They designed 4 types of supercharger including the turbo which was used for both the Liberty 12 and the Lion, so they were RAE turbos mounted on these engines, RAE did both pieces of engineering; the Lion was done also as a gered version and the blower dia was enlarged for turbo test serias 2. ; the turbo part gave all sorts of problems and so most work from 1925 onward was with mechanical; but that did not mean turbos were neglected. A couple of years ago I wrote a series on another bulletin board; if people are interested I can update and repost here.. any thoughts?
I have attached a page from the report and a pretty poor copy of a Fairey Fawn showing the turbine... streamlining caught on a little later in the period!
« Last Edit: May 15, 2014, 08:07:47 am by tartle »
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Offline J.A.W.

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Thanks T, engine development certainly got ahead of airframes in that period, & even ahead of themselves..
Metallurgy, pressure control & coordination were certainly problematic in early turbo installations.
& big powerful engines too, in themselves..
Viz the Napier Cub, the 1st 1,000hp aero engine - a feat - but with no reasonable prospect of practicable utility..

(& I read your early developments thread  - on another site, per previously listed link - & enjoyed it).
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Offline J.A.W.

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In this Sabre Tempest recognition film (featuring an early build 486 NZ Sqdn machine),
- the characteristic high rpm capability is clearly apparent, an advantage for high speed fighter flight.



Jim Sheddan, long serving 486 NZ pilot ( he made C.O.) on Typhoons & Tempests put it thusly..

"Of all the Allied fighters in action in the last 12 months of the war, the Hawker Tempest, powered by a
Napier Sabre sleeve valve engine was in a class of its own.
In the hands of an experienced pilot, it was more than a match for any aircraft flying on either side...
...A Merlin by comparison, was a slow revving motor, cruising revs being in the vicinity of 1,800 rpm
while maximum revs were in the 3,000 range. Thus there was a flat spot between when the pilot asked for
maximum effort...& received it. This time lag could be crucial when bounced by the enemy.
The Napier Sabre, by comparison, cruised at 3,500 rpm & had a maximum of 3,850.
There was so little difference between cruising & flat out that it could be claimed that a Tempest was almost
operating at its maximum performance at all times.
This had an advantage in that it was difficult for enemy fighters to position themselves to bounce..."

& confirmation of this is shown in the interrogation report of a captured LW fighter pilot..
..as listed in the USAAF Air Intel' Summary of 18/3/45..

Re:  the Tempest, it "...had superior speed & climbing ability which made it extremely formidable.
The apparently excellent field of vision afforded the Tempest - made it hard to surprise."
« Last Edit: May 17, 2014, 02:53:21 am by J.A.W. »
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Offline JFC Fuller

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Viz the Napier Cub, the 1st 1,000hp aero engine - a feat - but with no reasonable prospect of practicable utility..

The Cub was designed into the initial versions of both the entrants (Blackburn and Avro) for the 16/22 heavy torpedo bomber requirement- until somebody realised that an aircraft powered by a single 2,450lb engine with early 1920s reliability flying for long periods over water was a less than ideal prospect.

Offline J.A.W.

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Well,  risks - such as flying a Vimy - on long distance over-water routes were undertaken, with little
prospect of maintaining flight in the event of an engine failure..

However, the Cub was an example of the dreaded X-type..

Here, some details from 'Flight'..

http://www.flightglobal.com/pdfarchive/view/1922/1922%20-%200118.html
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Offline robunos

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Quote
...a pretty poor copy of a Fairey Fawn showing the turbine... streamlining caught on a little later in the period!

Here's the only image of a turbocharged Fairey Fawn I could find, and here's the write-up from Putnam's 'Fairey'...

"The supercharger used was a continuous-flow turbo-compressor with the  turbine driven by exhaust pressure through nine nozzles. It was mounted in  front of the engine, below the propeller, and this position necessitated the  use of the earlier type of side or lateral radiators. One of the first changes  which had to be made was the replacement of these with a special underslung  radiator with adjustable shutters.  The RAE tests started in March 1925 and continued for about three years.  Development was hampered by engine and blower failures and by the time  taken to make the necessary modifications — including, for instance, an  increase of internal clearances in the blower to prevent seizures with the  changes of temperature on climb and glide, the raising of the engine  compression ratio and the fitting of a bigger-capacity water-pump. In the end,  after considerable labours, times-to-height and rates-of-climb were showing  useful improvements on the standard figures in spite of the additional weight  and drag of the installations, and level speeds were also slightly better. But.  even with these improved results, it was concluded that the gains in climb and  ceiling were not enough to outweigh (at least with the Fawn) the performance losses near the ground because of the power absorbed by the blower and  because of the propeller pitch-angle which had to be used to obtain the better  performance at altitude."


cheers,
            Robin.     
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Offline tartle

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Robunos (Robin),
Thanks for that... adds to our pool of useful knowledge. When I've collated the test results I'll post a bit more performance data.
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

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And here's the Gloster Guan, also powered by a turbo-charged Napier Lion, from Putnam's 'Gloster'.

"The Guan was an experimental single-seat high-altitude fighter built to  flight test supercharged aero-engines. Similar in construction and appear  ance to the earlier Gorcock, the Guan had an all-metal fuselage and wooden  wings of the Gloster H.L.B. combination, which spanned 3 ft 4 in more  than the Gorcock with a 48 sq ft increase in wing area. It was Folland’s  intention to combine in one aircraft the Gorcock’s high top speed, which  was nearly 30 mph faster than contemporary Service fighters, with a substantial improvement in service ceiling and this he achieved.  Three Guans, costing £7,500 each, were ordered by the Air Ministry  early in I925 and design work began in February. The first aircraft, J7722,  was powered by a 450 hp Napier Lion IV engine fitted with an exhaust-  driven turbo-supercharger mounted externally under the propeller shaft.  This position for the supercharger resulted in a prominent array of external  ‘plumbing’ which was a feature of the Guan. Completed in June 1926,  J7722 was delivered to the RAE Farnborough in August. The second  Guan, J7723, was powered by a 525 hp direct-drive Lion VI, also fitted  with an exhaust-driven turbo-supercharger which was mounted on top of  the cowling above the propeller shaft. This aircraft was completed early  in 1927 and was delivered to Farnborough.  Although the supercharging enabled maximum power to be matintained  up to 15,000 ft, at which height the Guan had a top speed of 175 mph, and  the service ceiling was pushed up to 31,000 ft, the turbo-superchargers  were a continual source of trouble. The engine manufacturers made a  number of modifications to the units and the system, but very little improvement was achieved and the development was abandoned. This failure led  to the cancellation of the third Guan which was to have been powered by  the inverted, geared Napier Lioness engine similarly supercharged.  Before the programme was finally terminated, J7722 was fitted with a  Hele-Shaw Beacham constant-speed variable-pitch propeller."


cheers,
            Robin.
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Offline Basil

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J.A.W., thanks, interesting video to hear the sound of a sabre.

Offline J.A.W.

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J.A.W., thanks, interesting video to hear the sound of a sabre.

You are welcome B, there is something quite musical about the sound of an even firing 120` triple arrangement..

& Kermit Weeks intends to have a Sabre Tempest  in airworthy order again..
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Offline J.A.W.

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The final generation of piston powered fighters present an interesting contrast.
Here are the speeds attained  at sea-level by the top performers.
(IMO this provides a fair indication of the ever-sought balance - between engine out-put & aero-slick airframe)..

399mph Grumman F8-F2 Bearcat;
399mph Vought R-4360 Corsair;
400mph Vought F4U-5   Corsair;
406mph Hawker Centaurus Sea Fury;
408mph V-S Griffon 101 Spiteful F XVI;
412mph N.A.A. Merlin-9 Mustang P-51H;
418mph Hawker Sabre 7 Tempest F 6;
419mph Hawker Sabre 7 Fury F 1..

US figures are from 'Standard Aircraft Characteristics'..
- & British are from Boscombe Down/'Flight' archive..
 
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Offline PaulMM (Overscan)

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The final generation of piston powered fighters present an interesting contrast.
Here are the speeds attained  at sea-level by the top performers.
(IMO this provides a fair indication of the ever-sought balance - between engine out-put & aero-slick airframe)..

399mph Grumman F8-F2 Bearcat;
399mph Vought R-4360 Corsair;
400mph Vought F4U-5   Corsair;
406mph Hawker Centaurus Sea Fury;
408mph V-S Griffon 101 Spiteful F XVI;
412mph N.A.A. Merlin-9 Mustang P-51H;
418mph Hawker Sabre 7 Tempest F 6;
419mph Hawker Sabre 7 Fury F 1..

US figures are from 'Standard Aircraft Characteristics'..
- & British are from Boscombe Down/'Flight' archive..


There's less than 5% separating top from bottom, which says to me there is no effective difference between the performance of any of them.
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Offline J.A.W.

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Good to see some interest input-wise on the thread from the 'Poobah'..

Quite close indeed, in fact about as close as the closing/evading speeds of FW 190 JABOs attacking Blighty..
& then evading flat out.. & the Spitfires (too slow) & Typhoons (speed in hand) tasked with chasing them down..

- Or running down V1s going the other way across the channel on a heading for London..

If  a cyclist swishes close by you  while out strolling - with a + 20mph speed - does it seem significant?

Or try telling that to the copper in an unmarked patrol car you've just passed by at +20mph..
- over the limit - once s/he's pulled you over..
« Last Edit: May 17, 2014, 01:40:45 am by J.A.W. »
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Offline Jemiba

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Isn't that comparing apples and oranges ?

20 mph:

- Quite the limit for an untrained cyclist : 100 %
- In the mentioning speedin case, it's about 25 to 30 % above speed limit,
  depending on the country
- In the case of the mentioned aircraft, it's less, than the differences for the max.
  speed to be found in different sources.
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Offline tartle

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Reading, for example, the Decisive Duel, highlights how matching or exceeding, if only by 5mph, the speed of your opponent enables you to catch or escape in the right circumstance. if you are jumped then characteristics other than speed in a straight line counts... what this has to do with engine technology I am not sure. I suggest fighter strategy and tactics goes into another thread and we revert to engineering the difference in this thread.
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Offline J.A.W.

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Well T, 'power to fly = power to speed', & aero-engine designers sought to find the best balance..
Power/weight, frontal area, cooling technicalities, prop disc accommodation, & etc.

For fighters, engine characteristics ought to be different?  Yet often bomber engines were employed..

Oddly - in the case of the FW 190, the original BMW radial was replaced with a Jumo V12, & improved..

& US fighters drew criticism for not optimising coordinated power controls for the pilot,
but the US didn't seem to take note until the Merlin & FW 190 showed them what difference it made.
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Offline J.A.W.

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& T, are you able to elucidate on the reasoning behind R-R's engine team to reverse the Griffon crank rotation?

The 'unintended consequences' impact on Spitfire pilots was dire in more than a few instances..
Was it a packaging thing, or were balance/harmonics involved, hence the firing order change too?
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Offline tartle

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There was much work on the 1930s to standardise as much as possible to make wartime production across the nation as simple as possible; shadow factories were part of this; The direction of rotation on the Griffon was the result of the Society of British Constructors deciding in the late 1930s to standardise the direction of rotation as clockwise when viewed from the pilot's seat. All new engines would adopt this from then on... this actually meant only RR had to change.
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Offline J.A.W.

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Thanks T, & so the tens of thousands of Merlins built, - in fact outnumbered all the later 'standardised' types
- yet were not required to adhere to the same 'standard'..

Yet R-R did devise 'handed' Merlins for the D-H Hornet sans too much difficulty..
( Did the Twin Mustang use the same R-R set-up - or was the Packard Merlin 'handed' discretely?).

Took a good while to fit the 'standard' fighter instrument panel, & longer yet to tidy up the 'dogs breakfast' of control placements.. ..or even introduce pre-flight check lists, all these must've been costly in non combat losses..
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Offline J.A.W.

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Isn't that comparing apples and oranges ?

20 mph:

- Quite the limit for an untrained cyclist : 100 %
- In the mentioning speedin case, it's about 25 to 30 % above speed limit,
  depending on the country
- In the case of the mentioned aircraft, it's less, than the differences for the max.
  speed to be found in different sources.


No, since it is the speed relative to the observer..
 ..even if you were travelling at 300,000mph in space & another ship passed close by overtaking at 300,020mph
 - & moving away - it would be seen moving at an appreciably faster rate - relative to you..
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Offline tartle

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As the convention was for new designs the Merlin was not subject to 'the rule'; but the Griffon I onward was; curious what happens to 'national' standards... still happens, of course.
The Twin Mustang story goes something like this
The XP-82 was to be powered by two Packard-built Rolls-Royce V-1650 Merlin engines. Initially, the left engine was a V-1650-23 with a gear reduction box to allow the left propeller to turn opposite to the right propeller, which was driven by the more conventional V-1650-25. In this arrangement both propellers would turn upward as they approached the center wing, which in theory would have allowed better single-engine control. This proved not to be the case when the aircraft refused to become airborne during its first flight attempt. After a month of work North American engineers finally discovered that rotating the propellers to meet in the center on their upward turn created sufficient drag to cancel out all lift from the center wing section, one quarter of the aircraft's total wing surface area. The engines and propellers were then exchanged, with their rotation meeting on the downward turn, and the problem was fully solved. The first XP-82 prototype (44-83886) was completed on 25 May 1945, and made the type's first successful flight on 26 June 1945. This aircraft was accepted by the Army Air Forces on 30 August 1945, whose officials were so impressed by the aircraft, while still in development, that they ordered the first production P-82Bs in March 1945, fully three months before its first flight.... but then they decided to go to Allison for a less powerful but all-American engine. The 80-odd  Merlin P-82Bs were assigned to training and for the first time the Trainee pilots found they had a trainer with more performance than the operational model!
This ref may be of interest.
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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Cheers for that T,

The Twin Mustang/Do 335/D-H Hornet/Tigercat all present interesting attempts at fast/last piston twins..

AFAIR, the USAAF considered the USN R-2800 powered Tigercat - even getting one to test,
- & although they got a Do 335 (& Meteor) too, I don't know if they ever got a Hornet..

Likewise, the Brits got an F-7F for evaluation, but no P-82..
Two Merlins = Too similar?

Both NAA & USAAF were reportedly irritated by having to accept the Allison-virtually a 'shotgun marriage'
- said to be via the political influence of a prominent GM shareholder within the Truman administration..
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Offline J.A.W.

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The P&W R-2800 was capable of significant performance increments over its progressive development.
A good part of this was its capability of accepting increased boost levels , even if for time periods that were,
as LJKS put it.. "ephemeral", & were dependant on high test fuel plus ADI...

The P-47M, a late Thunderbolt development that was initially touted as a U.S. V1 interceptor
(but proved both too late & anyway - too slow - at low altitudes) was run at supercharger boost levels in
excess of 70" Hg (+20lb) , & provided excellent high altitude performance for the last 8th AF air superiority
 unit flying them, the 56th FG, - but not without engine issues.. ..like a TBO of 15-30hrs.. ..see this link below..

http://www.wwiiaircraftperformance.org/p-47/p-47m-20march45.jpg
« Last Edit: May 20, 2014, 01:02:29 am by J.A.W. »
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Offline J.A.W.

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This 'Flight' article has a chart showing the power at altitude characteristics of the R-R Griffon 3-speed/2-stage 100 series V12.

http://www.flightglobal.com/pdfarchive/view/1946/1946%20-%200062.html
« Last Edit: May 21, 2014, 12:25:26 am by J.A.W. »
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Offline JFC Fuller

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If you use the search function you will find we already have a thread on that:
http://www.secretprojects.co.uk/forum/index.php/topic,13990.0.html
« Last Edit: May 21, 2014, 08:16:52 am by JFC Fuller »

Offline J.A.W.

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If you use the search function you will find we already have a thread on that:
http://www.secretprojects.co.uk/forum/index.php/topic,13990.0.html


Thanks for posting the link to the dedicated Griffon thread JFCF..
.. however, as an alternative development to the turbocharger method of maintaining induction charge/power to fly for the piston engine at increasing altitude - it does belong here too..
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Offline J.A.W.

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As the convention was for new designs the Merlin was not subject to 'the rule'; but the Griffon I onward was; curious what happens to 'national' standards... still happens, of course.
The Twin Mustang story goes something like this
The XP-82 was to be powered by two Packard-built Rolls-Royce V-1650 Merlin engines. Initially, the left engine was a V-1650-23 with a gear reduction box to allow the left propeller to turn opposite to the right propeller, which was driven by the more conventional V-1650-25. In this arrangement both propellers would turn upward as they approached the center wing, which in theory would have allowed better single-engine control. This proved not to be the case when the aircraft refused to become airborne during its first flight attempt. After a month of work North American engineers finally discovered that rotating the propellers to meet in the center on their upward turn created sufficient drag to cancel out all lift from the center wing section, one quarter of the aircraft's total wing surface area. The engines and propellers were then exchanged, with their rotation meeting on the downward turn, and the problem was fully solved. The first XP-82 prototype (44-83886) was completed on 25 May 1945, and made the type's first successful flight on 26 June 1945. This aircraft was accepted by the Army Air Forces on 30 August 1945, whose officials were so impressed by the aircraft, while still in development, that they ordered the first production P-82Bs in March 1945, fully three months before its first flight.... but then they decided to go to Allison for a less powerful but all-American engine. The 80-odd  Merlin P-82Bs were assigned to training and for the first time the Trainee pilots found they had a trainer with more performance than the operational model!
This ref may be of interest.



T, further to your Merlin twin directional rotation factor.. ..here is a 'Flight' article that shows that the Hornet
rotated opposite to the P-38 (& revised P-82).. oddly enough..

http://www.flightglobal.com/pdfarchive/view/1947/1947%20-%200004.html
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Offline Jemiba

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T, further to your Merlin twin directional rotation factor.. ..here is a 'Flight' article that shows that the Hornet
rotated opposite to the P-38 (& revised P-82).. oddly enough..

Good point, maybe the fuselage of the Hornet acted as a kind of end plate for the center wing, missing in
the F-82 ?
It takes a long time, before all mistakes are made ...

Offline tartle

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As the Hornet was intended for carrier operations too, it was designed to have a reversed rotation of one of its propellers to counteract torque effects. This was done by inserting an idler wheel in the reduction gear of one of the engines. Initial operation showed it tended to overheat at the tooth contact... very serious. Special injection jets were introduced to ensure there was an oil film on the contacting surfaces of the gear teeth. There was also some rearrangement of 'accessories' e.g moving water pump from bottom of the wheelcase to the side of the crankcase where it was driven by a drive originally intended for a generator. Result a very low drag engine nacelle.
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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T, further to your Merlin twin directional rotation factor.. ..here is a 'Flight' article that shows that the Hornet
rotated opposite to the P-38 (& revised P-82).. oddly enough..

Good point, maybe the fuselage of the Hornet acted as a kind of end plate for the center wing, missing in
the F-82 ?



My thoughts exactly J, it does appear that the NAA P-82 team picked up the Hornet Merlin rotation with
the 'handed' R-R mills - only to find that the earlier P-38  rotation orientation was in fact necessary..

The 'handed' Allison V-1710s did not use the R-R gearing solution for reversing prop rotation - but spun the crank
in opposite rotation - like the Griffon..
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Offline J.A.W.

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This 'Flight' article on the civil Centaurus includes a power ratings @ altitude graph..

http://www.flightglobal.com/pdfarchive/view/1949/1949%20-%201484.html
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Offline J.A.W.

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This period German document shows the enhanced boost levels applicable for DB 605 V12 mills..
.. when high-test C 3 fuel was available over B 4 type, raised from 1.8 ata to 1.98 ata..

http://www.kurfurst.org/Engine/Boostclearances/DB_Niederschrift6730_DB605DBDC_20-1-45.pdf
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Offline Jemiba

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Not sure, that it really shows, how the boost level of the DB 605 could be increased.
To my opinion, this report rather is about, how boost level (and power output !) had to
be decreased, because of low fuel quality !
The change to C3 was principally rejected in that paper, as final testing still wasn't finished.
Testing of four engines with boostlevel set to 1.98 ata brought negative results (no further
explanation, judging further text probably thermal loads became a problem), operational use
was only allowed for a single fighter group and maybe for single recce aircraft, but not fleet
wide.
Nevertheless an interesting paper, one of the last paragraphs mentions a planned comparison
of the Me 109 and the Mustang, and although no flights were conducted, the comparison of the
overall quality is said to have brought devastating results.
It takes a long time, before all mistakes are made ...

Offline tartle

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More on the Hornet installation:
The DH 103 Hornet, as one of the smallest twin-motor aeroplanes in the world, presented quite a problem in accommodating its power plants in the airframe.
To meet the problem, the supercharger air intake was extensively modified and the 130 and 131 were the first Merlins to incorporate down-draught induction systems. To eliminate the air scoop as used on the Mosquito, ducted air intakes were faired into the leading edges of the wings. The coolant pump was also moved from the bottom of the motor to its starboard side, and these modifications resulted in a bottom cowling line free from excrescences and of symmetrical form-an ideal arrangement for a high-performance fighter.
The engines were mounted low to obtain a smooth airflow over the wing, exhaust ejection below the wing, a short chassis leg below the nacelle for easy stowage when retracted, and the best possible pilot's view.
Propellers rising inboard were tried first as being preferable for fore-and-aft stability, but they blanketed the rudder at low speeds and rendered it ineffective for correcting swing on the ground. Propellers rising outboard were therefore adopted and the stability standards secured by tail plane dimensions and stability weights.
So not just the Twin-Mustang had to swap handed engines side to side.
[info from here which also discusses the Peregrine installation in Whirlwind]
Also attached is the Mossie nacelle for comparison.
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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Thanks J & T, for that input..

Here is a performance graph showing speed  @ height - for the new twin-engined  RAF fighters,
Hornet & Meteor, - along with the fast Merlin & Griffon single engine powered RAF fighters.

http://www.wwiiaircraftperformance.org/Hornet/Hornet_I_Level_AFDS.jpg


The Mosquitos equipped with 2-stage supercharged Merlins featured a longer nacelle yet -with the engine
air scoop located below the spinner, similar to the Mustang.

The Hornet F 1 - when tested with the initial typical De Havilland-shaped fin/rudder did exhibit directional
stability issues ( no minor thing on a twin ) & had a fin fillet added - similar to the Tempest..

(Most late production, high powered piston engine fighters required & received more tail aero surface area).
« Last Edit: May 26, 2014, 08:05:20 pm by J.A.W. »
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Offline J.A.W.

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& the 'shrouded' ( flame dampened for night flying) Mosquito exhaust arrangement cost ~15mph..

http://www.wwiiaircraftperformance.org/mosquito/dk290-b-.pdf
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Offline Hot Breath

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As the thread devoted to large aero-engines is locked, I'll post my question here.  What was the exhaust arrangement intended to be on the Rolls Royce Exe?  Was it one set of exhausts per side, with two cylinder banks collected together or was it like the Vulture which had two sets of exhaust per side?

Offline J.A.W.

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See this 'Flight' article , H-B..
.. which conveniently has a picture of the flying Exe - to contrast with the Vulture arrangement shown stat below..

http://www.flightglobal.com/pdfarchive/view/1948/1948%20-%200146.html
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Offline J.A.W.

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This chart shows the performance available to the early series Merlin Mustang ..
 ..running on various supercharger ratios & boost settings ( & at low AUW)..

http://www.wwiiaircraftperformance.org/mustang/P-51_B_High_Speed_Performance.jpg
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Offline J.A.W.

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The Brits & the USN weren't sold on turbos.. - not for fighters at least- & the R-R Merlin in the Mustang showed why..

However, the USAAF did give turbo fighters a good go, even if they were expensive/complicated/bulky in usual US-style..

Here, the G.E. sales pitch for the big ol' Thunderblot..

http://rwebs.net/avhistory/opsman/geturbo/geturbo.htm
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Offline J.A.W.

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& NAA/Packard felt it worthwhile to see the ADI R-2800's commendable 70" of boost..
.. & go to 90''/ADI for the P-51H/Merlin V-1650/9..

Here is the power chart.. http://www.wwiiaircraftperformance.org/mustang/p-51h-powercurve.jpg

« Last Edit: May 29, 2014, 12:20:27 am by J.A.W. »
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Offline J.A.W.

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& here..
  http://www.wwiiaircraftperformance.org/mustang/Comparative_Fighter_Performance.jpg
A USAAF graph equivalent to the British comparison(post #241)..
..between late piston-powered fighter performance & the new jet job..

& with the caveat however, that judging by the date.. ..it is an estimation..
..Also, the Mustang is at 70" boost, same as the P-47, & 20" less than the max of 90" Hg/MAP - it was cleared to run..

« Last Edit: May 30, 2014, 12:29:10 am by J.A.W. »
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Offline tartle

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There is an interesting 'manual' on turbosuperchargers here on Randy Wilson's website along with much other interesting material. [someone has pointed out this is the same link as J.A.W.'s in #246 above ... great minds or a lazy mind?]
« Last Edit: May 30, 2014, 04:43:42 pm by tartle »
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Offline J.A.W.

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& the 'bomber' Junkers Jumo 213 V12 - as applied to the FW 190D.. ..engine finally runs ~5min in..

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Offline J.A.W.

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This USAAF appraisal of the Lancaster shows enthusiasm for the "many automatic features" applied to the engines..
..including cooling, mixture & etc settings , - just as they did for the same measures applied to the Merlin in the Mustang..

http://www.wwiiaircraftperformance.org/Lancaster/Lancaster_Eng-47-1658-F.pdf
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Offline J.A.W.

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This article by Kevin Cameron considers the thermal load/TBO aspects of piston engine power outputs..

http://www.cycleworld.com/2014/05/23/engine-tech-how-much-power-for-how-long-by-kevin-cameron/
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Offline J.A.W.

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From the long 'much maligned British automotive engineering' dept..

Bernard Hooper was a Norton engineer back in the 70's - with some innovative ideas, & has persevered,
 viz.. http://users.breathe.com/prhooper/uav.htm

Back in the day, his bosses felt going down the Cosworth F1 path was the better option, but they were wrong..
As can be seen in this well written technical appraisal of the engine  by Kevin Cameron..

http://classicbike.biz/Norton/Mags/1970s/Cosworth-Norton.pdf
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Offline tartle

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Fascinating... I guess if we only have two tools-hubris and a hammer - we'll see each problem as needing a nail!
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Offline J.A.W.

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107 years ago, Glenn Curtiss was the "Fastest Man on Earth" at 136.36mph - with a V8 aero-engine of his own manufacture..

This speed was achieved across a measured mile at sea level, in fact - along a Florida beach, & riding his motorcycle..

http://www.odd-bike.com/2012/11/curtiss-v8-worlds-fastest-motorcycle.html

After his first flight Curtiss was quoted.. "Not bad sport, but there's no place to go"..

So he designed sea planes, & his aircraft were the first flown from warships & to cross the Atlantic..

« Last Edit: June 10, 2014, 12:24:24 am by J.A.W. »
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Offline tartle

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Curtiss was designing his own motor bike engines and then in 1907 Alexander Graham Bell asked him to design an engine for a heavier than air flying machine... the rest ids history.. the book I have just finished and nearly edited features Curtiss.His later (WW1)  engines were not as robust but that is a story for elsewhere.
The picture below shows his Reims racer at Reims 22-29 August 1909 with his new light-weighted V8 water cooled engine.
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Offline mz

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SDASM archive on flickr has lots of photos of similar flying machines and of Curtiss himself. It's a bit hard to know when they are photos of a later replica though.

Offline tartle

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I can vouch for that one as it was taken on a visit by Maurice Egerton to Reims and I have catalogued many others on the other machines too! Maurice was a keen photographer.
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you.” - Paul MacCready, aeronautical engineer.

Offline J.A.W.

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Curtiss was designing his own motor bike engines and then in 1907 Alexander Graham Bell asked him to design an engine for a heavier than air flying machine... the rest ids history.. the book I have just finished and nearly edited features Curtiss.His later (WW1)  engines were not as robust but that is a story for elsewhere.
The picture below shows his Reims racer at Reims 22-29 August 1909 with his new light-weighted V8 water cooled engine.


The Curtiss 'Golden Flyer' which won G.C. the Bennett Trophy at Rheims..

& his 'Gold Bug' got him a law suit from the Wright Bros, when he sold it - over his development of ailerons..

The link in post #255 has a brochure featuring his line-up of aero-engines, listing  weights/powers/cooling/configurations..
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Offline tartle

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The Golden Flyer is a different aeroplane to the one that went to Reims... Curtiss built a new aeroplane incorporating lessons and to take account of the racing that he would be doing.
We should start a new thread for this.
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Offline J.A.W.

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Well, T, if you've got a proper book on the subject, I'll leave it to you..

& here - a vid which demonstrates the sophistications of the technicalities pertaining to operating a Corsair.
( & shows why the Americans were so impressed with the automation of controls - as developed over the Atlantic)..

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Offline J.A.W.

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Here, a compact currently commercially available piston engine - that offers upwards of 200hp from 95lbs, un-boosted..

http://www.aaenperformance.com/V4_racing_engine.asp
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Offline J.A.W.

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This vid shows the pre-flight engine protocols for the Bf 109G, & provides a Euro-contrast with the fiddle-faddlin' F-4U..

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Offline J.A.W.

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Manufacturing Merlins, the Packard way..

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Offline tartle

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JAW... very interesting. There are some IWM films of Merlin production at Hillington and Trafford Park but I've not found them on the web yet.
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Offline J.A.W.

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Glad you found it so, T..

Could this be one that you are thinking of?


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Offline tartle

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Ta.. and this... Hillington did most manufacturing in-house as the 'hi-tech' production infrastructure in Glasgow did not really exist... hence RR had to do it all from necessity not choice.
« Last Edit: June 15, 2014, 04:12:49 am by tartle »
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Offline J.A.W.

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Good stuff, T..
& the same sorry skill base issues applied for Napier/EE in Liverpool..

 ..Don't suppose there is a similar film about Sabre production though, too hush-hush at the time - or something..
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Offline tartle

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there is a similar story about the shadow factories for Bristol engines tooo which were supposed to be better as Fedden's team spent more time on DfP ... and car firms made up the labour/management pool... first signs of demise of car industry?
Oh for a Napier film! best available stuff seems to be pix at IMech EAlso hard to find engine info at Kew ... my last frustrating half day -their cameras were playing up and I did not find much beyond continual asking for more cash to spend on factory and test facilities and not much on engine itself!
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Offline J.A.W.

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This 'Aeroplane' article featuring the R-R Griffon shows useful schematics of supercharger drives,
& an output figure comparison with the R-R Eagle V12 of WW1 - as a means of showing piston engine power progress.

http://www.spitfireperformance.com/RR-Griffon.pdf
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Offline J.A.W.

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Work/research still continues on the venerable piston engine..
This paper considers tribological effects on piston to cylinder liner surface patterning.

http://www.federalmogul.com/en-US/Media/Documents/HighqualitySAEpaper200909PFL1163manuscript2.pdf
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Offline Kevin Renner

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Here, a compact currently commercially available piston engine - that offers upwards of 200hp from 95lbs, un-boosted..

http://www.aaenperformance.com/V4_racing_engine.asp

Less than 5 miles from the house actually

Offline J.A.W.

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Hey, K.R., that's great, can you get down there with an HD Video camera..
& put us up some high-production value 'footage' of the machine on dyno test?

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Offline J.A.W.

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USAAF statistical chart showing WW2 piston engine overhaul hours by type..

http://www.usaaf.net/digest/t115.htm
« Last Edit: June 28, 2014, 08:15:07 pm by J.A.W. »
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Offline tartle

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JAW,
A useful find!
Must do some bmep calculationss to see what accounts for differences... configuration, performance per unit of ? or mechanical design...tbc.
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Offline J.A.W.

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Yes it is a bit interesting T, but whether the time difference spent on fettling the two V12s was due to the..
..typically Brit nuts 'n' bolts construction architecture of the Merlin, & unfamiliarity with such - or due to being run harder..
..may also be a point of inquiry.. ..certainly the number of parts listed per the Merlin is rather larger than the Allison..
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Offline alertken

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1820 consistently lower than 1830 - the competing engines for C-47, yet post-War civil preference was for Pratt.

Good luck in analysis, but operational, rather than design technical issues may be significant: e.g: this is CONUS Depots: battle damage/ misuse may have been handled more in Theate Depots

Offline JFC Fuller

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Tartle,

This may interest you. I found yesterday a mid-1944 reference to a "three stage" Merlin to possibly be available in 1946 in relation to the Spiteful. I have nothing more than that I am afraid, no type numbers, only this one reference. Perhaps you are aware of some work undertaken in this direction?

Offline tartle

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Fascinating,
It is possible a designer schemed out such a concept but I haven't so far found any evidence.
Is there a possibility that this is similar to a reference I found to a 3-stage supercharger for the Griffon that on chasing it through the paper trail turned out to be a 3-speed supercharger? Not knowing the provenance of what you found I can only speculate...
what are your thoughts?
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Offline JFC Fuller

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I actually mused exactly the same thing, that perhaps it was a confused reference to a Merlin with the sort of two-stage/three-speed supercharger used on the 100 series Griffon. The original Merlin engine schemed for the Merlin Spiteful variant was the RM.16SM (as used in the Spitfire PR.Mk.X). Of equal interest, to me at least, was an assertion that a Spiteful with the Merlin would have approximately 8-9% more range than the Griffon powered version.

On a lighter note I found myself having considerable sympathy for the people at RR and Supermarine in particular. After all the work undertaken on developing the Spiteful and the high-altitude Griffon to power it the Air Staff decided in mid-late 1945 that their only interest in the type was as a low altitude attack aircraft, so the whole programme was held up as Supermarine worked to install the ability to carry a 1,000lb bomb under each wing. 
« Last Edit: June 29, 2014, 05:37:33 am by JFC Fuller »

Offline JFC Fuller

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I didn't think this picture would work, but it does just about, its from the spiteful files I was looking at, Griffon 65, versus Merlin 66 versus RM.16SM:
« Last Edit: June 30, 2014, 01:21:15 pm by JFC Fuller »