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Author Topic: Rolls Royce Viper/ Bristol Siddeley Orpheus  (Read 25574 times)

Offline Jemiba

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #15 on: February 04, 2012, 06:42:05 am »
About Michel Wibault and the Gyropter, you can have a look here, too :
http://www.secretprojects.co.uk/forum/index.php/topic,2118.msg118929.html#msg118929
 
It takes a long time, before all mistakes are made ...

Offline tartle

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #16 on: February 04, 2012, 07:32:20 am »
kaiserbill,
The Orpheus 12 and its reheat version sound fascinating... I know where there is more data but I am engaged on writing material for Maurice Egerton's 1909-1914 aeroplanes mainly with a Gnome rotary engine to be used in an exhibition from 24th March to end April at Tatton Park's mansion... then I'll devil the data to complete the Orpheus story.
Jemiba,
Thanks for thread... Wibault died before the BE.53 ran and Kestrel flew .. so he never saw what a great aircraft he inspired... even if it was a mile away from his sketches, but I wonder what he would have made of this?
In summary the design iterations that Wibault was involved with after Bristol picked up the idea and ran with it are (hopefully this ties in with what I have already written!):
The BE48 replaced the centrifugal compressors with the axial Olympus l.p. compressor, using it as a fan;
The BE52 replaced the Orion and its gearbox with the Orpheus, but retained the separate intakes for the core engine;
The BE53 did away with the separate intake and used the fan to supercharge the core, giving more power;
The BE53/2, the first Pegasus, introduced contra-rotation and confirmed the use of four nozzles rather than three.
« Last Edit: February 05, 2012, 05:10:06 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 tartle

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #17 on: February 04, 2012, 12:48:54 pm »
sealordlawrence... you suggested we compare a Viper and an Orpheus... well here goes


Engine mark                 Viper 600             Orpheus 803

configuration                single-stage       single-stage
compressor stages           8                              7
combustor                      annular             cannular- 7 tubes
turbine                           two-stage         single-stage
T/O thrust lbt                 3,750                  5,000
Air mass flow lb/sec          58.4                   84
Pressure ratio                 5.8:1                   4.14:1
length in                           85.0                   96.1
diam in                             24.5                   32.4
weight lb                         790                     975
t/w                                   4.75                    5.13

It is not easy to deduce which engine had the earlier birth as redesign and incorporation of new technologies has proceeded apace on both engines. Also the duty is different so optimisation happens around different parameter points. However, as always, t/w ratio is an indicator. The most fundemental difference between the configurations is the bearing arrangement: 3 bearing arrangement on the Viper but only 2 on the Orpheus. This was really the first engine in Stanley Hooker's career that presented him with a clean sheet of paper... so he decided on a two-bearing arrangement as a way to achieve lower weight and then designed other components to achieve a stiff enough rotor assembly to avoid resonance issues. He obviously succeeded!

Viper engine production ended in 1996, but refurbished engines were being supplied as recently as 2009 for newly-built Macchi MB-339CD trainers for the Malaysian Air Force. Production in Britain by what were successively Armstrong Siddeley, Bristol Siddeley and Rolls-Royce exceeded 5,600.
« Last Edit: February 05, 2012, 05:07:32 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 tartle

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #18 on: February 05, 2012, 04:15:16 am »
In 2008 Flight ran a 100 greatest forum and the Viper was proposed for the list. I reproduce one of the comments received here:
"
It was with some interest that I read your comment about the Rolls Royce Viper engine, which was designed and initially developed by Armstrong-Siddeley Aircraft Gas Turbines, of Parkside Coventry.
As a young graduate engineer in the design and evelopment department of Armstrong-Siddeley's from 1949 to 1951 I had been engaged in the development of the  Armstrong-Siddeley Mamba turbo-jet and its sister engine the Armstrong-Siddeley Adder pure-jet engine. Both of those were excellent engines with a small frontal area profile and individual combustion cans. However they both suffered to some extent from problems of matching the turbines to the axial compressors.
The Viper was a new design to a Ministry specification for an expendable jet engine to power the Jindivik target towing aircraft being developed for use at the target range at Woomera in Australia. Having had the experience of working on the Adder, it fell to me to arrange and carry out the very first-ever test on the first prototype Viper, which, if I can recall correctly was in April 1951. John Marlow was the Chief Development Engineer and he was present during that test.  The main functions initially being recorded were thrust and fuel consumption. After going through the preliminary run-up procedures, we  put some power on to the engine and on calculating the specific fuel consumption, Johnnie Marlow thought I'd got something wrong, so would I do it again. I repeated the calculations with Johnnie looking over my shoulder and, agreeing with what I did,   He was totally astounded at the result and performance and was immediately and joyously telling all around that at last Siddeley's had matched a turbine and a compressor.
The prototype was quite remarkable. The first few rows of the axial compressor had plastic blades, the oil pumps for the shaft bearings were simple plunger pumps which were  bought from the local motor cycle  makers. However, part of the real success was annular combustion chamber with its inherent simplicity.  Siddeley's had already had extensive experience of annular combustion chambers with their Sapphire engine, which in fact was used by the US Army to power their fleet of Canberra bombers which they built under licence, although I believe that the original annular combustion chambers were inherited from Metrovickers whose designs had been sold to Rover cars before being transferred to Siddeley's.
Eventually Siddeley's were merged with Bristol Engines to form Bristol Siddeley, which eventually was absorbed by Rolls Royce who continued and advanced the Viper design to what is indeed the longest production aircraft engine in the business. I believe it is from that merger that most Rolls engines have the pre-fix RB.
Shortly after running the Viper test, I left Coventry to take up an academic lecturing post in Aberdeen, where I eventually became Associate Head of the School of Mechanical and Offshore Engineering in what is now the Robert Gordon University.  But I look back on those days at Parkside and the testing bays at Ansty with fond memories and some pride.
 
Regards,
 Bert Hosie, BSc,CEng, FIMechE, Fellow of RGU,  Inverurie, Aberdeenshire."
"... 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 kaiserbill

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #19 on: February 07, 2012, 04:21:39 am »
Tartle, thank you very much for the very informative replies.
 
Extremely interesting.
 
One wonders why the Orpheus, particularly the Orpheus 12, never found an application. The Fiat G91 seems to have been a tailor made platform, particularly when one considers that it eventually ended up with 2 re-heated turbojets. Probably a time scale issue?

Offline tartle

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #20 on: February 09, 2012, 04:32:28 pm »
kaiserbill... it is interesting that the thrust of 2 J-85 = Orpheus 12... I wonder if the reason to switch was that newer rival aircraft had two engines and a reason for that was greater chance of surviving battle damage in a close support role? Also America might give more political support to Italy's foreign sales if at least the USA got the engine orders?
"... 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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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #21 on: February 10, 2012, 02:02:49 am »
kaiserbill... it is interesting that the thrust of 2 J-85 = Orpheus 12... I wonder if the reason to switch was that newer rival aircraft had two engines and a reason for that was greater chance of surviving battle damage in a close support role? Also America might give more political support to Italy's foreign sales if at least the USA got the engine orders?


Would also have been an obvious candidate for the later Gnat variants but that design moved towards RR RB153's, supposedly because of delays in the Orpheus programme.

Offline kaiserbill

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #22 on: February 10, 2012, 04:11:48 am »
kaiserbill... it is interesting that the thrust of 2 J-85 = Orpheus 12... I wonder if the reason to switch was that newer rival aircraft had two engines and a reason for that was greater chance of surviving battle damage in a close support role? Also America might give more political support to Italy's foreign sales if at least the USA got the engine orders?
  Indeed, the J-85 powered G-91Y was what I had in mind.
And the US connection to the G-91, particularly the initial US funding, is what crossed my mind too re afterburning engine choice.
 
Interestingly, I seem to recall Northrop entered their N-156 into the original competition that was won subsequently by the G-91.
So, full circle engine wise, perhaps?

Offline tartle

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #23 on: February 11, 2012, 12:56:40 pm »
The Orpheus 12R version of the 703 engine was offered to NATO for the upgrades of their European fighters and was rejected. However the Indian Gas Turbine Research Establishment in Bangalore worked presumably in cooperation with Bristol to develop over the period 1959-61:
-Design and development of a "1700K reheat system" for the Orpheus 703 engine to boost its power. The redesigned system was certified in 1973.
-Successful upgrade of the reheat system of the Orpheus 703 to 2000K.
-Improvement of the Orpheus 703 engine by replacing "the front subsonic compressor stage" with a "transonic compressor stage" to increase the "basic dry thrust " of the engine.

The last item looks like the civil upratings at Bristol so one wonders who developed what especially in light of the subsequent slow development of an Indian 'indigenous' engine.

There is a 703 in the Deutches Museum in Munich according to a Flickr photoposter
His photo is below [ a very high res is on his Flickr site]:
« Last Edit: February 11, 2012, 01:04:21 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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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #24 on: February 12, 2012, 04:22:10 am »
On a consortium of Indian Websites I found this intriguing comment:
"HF 24, an aerodynamically clean aircraft, capable of super sonic performance, was designed around an engine yet to be developed. Bristol Siddeley offered the BOR 12, a reheat variant of the Orpheus 703 as a power plant for HF 24 to us, as well as the NATO countries. When the NATO countries rejected the offer, Bristol Siddeley proposed its development at a cost of Rs 5 crores to Krishna Menon then Defence Minister who rejected it. It was a fatal error of judgment- in that HF24 never achieved its design performance. Its development violated a basic principle in aircraft design during those days: Proven engine and a new airframe. Never a new engine and a new airframe." ref

It seems that plenty of Defence Ministries, then as now, learn the lessons. As someone said it wasn't Deja Vu but Vu Deja.. you enter a familiar situation and treat it as though you've never been there before!
"... 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 kaiserbill

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #25 on: February 12, 2012, 11:24:46 am »
Had forgotten about the Marut, Tartle.
 
I remember now that it's performance was limited by it's engines, and that expected engine developments ensured that its performance remained pedestrian to what was initially envisaged and designed by Kurt Tank. It was designed as an aircraft with speeds of around Mach 2.
 
 

Offline tartle

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #26 on: February 17, 2012, 04:18:35 pm »
The Marut story has been told here. The relevant bit to our engine rambles is:
Continued Development
With the completion of Kurt Tank's tenure in 1967, responsibility for Marut development had passed to S.C. Das and an all-Indian team which produced the Mk.1T tandem two-seat trainer. The two prototypes of the trainer (BD 888 and 889) were the 46th and 47th Marut airframes, and the first of these was flown on 30 April 1970 by the then chief test pilot, Wg. Cdr. R.D. Sahni.
The essential difference between the single and two-seat versions of the Marut was the removal of the MATRA rocket pack featured in the former to provide space for the second cockpit. The minimal airframe changes required for the Mk.1T resulted in low development costs and almost total spares interchangeability. The second prototype Mk.1T was flown in March 1971, and the first of these entered squadron service in early 1975.
The search for a suitable engine continued even after the Maruts went full ops. In September 1966, the MoD announced that flight testing had begun on the third pre-production aircraft (as HF-005) designated Mk.1A  with an afterburning Orpheus 703 with an 18% greater boost than the original at 5,720 lb. (2 595 kg). By 1970, two more Maruts, designated Mk.1R, were brought into the afterburner development trials. Unfortunately, the programme suffered a severe setback when, on 10 January 1970, the first of two Mk.1R prototypes (HF-032) being flown by Gp. Cpt. Suranjan Das  crashed just after take-off.
India's foremost test pilot was the unfortunate victim of this crash. At the time it was rumored that one of the engines had completely failed and that there may have been a partial failure of the second engine. However, the official inquiry attributed the accident to malfunction of the canopy locking system. The Mk.1R prototype had been fitted with a hinged clamshell-type canopy in place of the earlier sliding canopy, and the failure of the locks and the sudden opening of the canopy, resulting in rapid decay of speed at a critical stage, proved fatal.
This set the programme so back, that the final stages of the flight test programme, using the second Mk.1R (BD 884), were achieved only in 1973. This airframe had a modified wider aft fuselage. The Orpheus 703 afterburning system had progressed to provide a 27% boost, giving 6160 lbs. (2 794 kg) of thrust, but the performance increment that it provided the Marut was insufficient to result in a production order for the Mk 1R. By the late 1970s, HAL entered into discussion with Rolls-Royce about using the Turbomeca Adour twin-spool after burning turbofan to power the Marut. The projected Adour-powered fighter was designated as the Marut Mk 2.
The Rolls-Royce RB.153 was considered for a while, but Hindustan Aeronautics was neither able to accept the terms of the proposed contract nor, at the time, was ready to consider the major redesign of the fuselage that adoption of the RB.153 would have entailed. In the event that by the early 1980s, the Air Staff requirements for a TASA (Tactical Attack and Strike Aircraft) and a DPSA (Deep Penetration and Strike Aircraft) were fulfilled by foreign aircraft, the need for a upgraded Maruts became somewhat superfluous. And by the mid-1980s enough Jaguars and MiG-23BN/27s were joining the IAF, that the Marut programme no longer remained viable.
No.10 Squadron gave up its Maruts in August 1980 and by the following year enough MiG-23BNs were available to allow No.220 Squadron to begin conversion. The last unit to give up its Maruts was No.31 Sqn, whose aircraft were finally withdrawn in mid-1990. And so ended the saga of India's first, and until the LCA flies, India's only home- grown fighter programme. In retrospect, despite its audacity, the Marut progamme helped lay the infrastructure for an Indian aviation industry.


A pilot commented:
The Marut was the brain child of Dr.Kurt Tank a German designer, who had been hired by the Indian Government to design a Mach 2 fighter bomber.
The Marut was a versatile fighter bomber, but it was underpowered and thus achieved speeds of Mach 1.1 at the maximum. But in two wars with Pakistan not a single Marut was lost in air combat. The Marut was twin engined and seated a crew of two.No 10 squadron was equipped with the Marut. Many attempts were made to get a more powerful power plant for the Marut, including an Egyptian engine. But they were not a success and the Western powers were reluctent to give a power plant. But despite these limitations the Marut gave excellent service to the IAF
Pilot_micha's photostream on Flickr photographed the Marut and also the Spanish Ha 300, which also used the Orpheus 703. I append 2 below but there are more pics available
« Last Edit: February 18, 2012, 02:35:07 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 charleybarley

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #27 on: December 11, 2012, 01:32:34 pm »
A question on the Orpheus 101:
I remember as an apprentice, in 1972, measuring some 2nd stage compressor stator tip clearances from superX? linac? pictures for the full running range (used a microdensitometer).
This was in connection with some compressor failures.
Does anyone have any recollection on what planes would likely have prompted the investigation?
eg say 3 accidents in 1971.

Offline kaiserbill

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #28 on: December 12, 2012, 04:20:46 pm »
That Orpheus 12 with afterburning actually sounds like quite a missed opportunity.
 
I can actually think of quite a few aircraft that may have benefitted from an engine in that class.
 
Any idea what it's physical dimensions were?

Offline tartle

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #29 on: December 13, 2012, 03:03:49 am »
I don't have the dimensions to hand for the BOr12 but this might help:
The Aerfer Leone was being built with a BOr12 engine; it had a wingspan of 6.93m; length 10.6m; height 3.32m.
The cross-section below has the engine shown so we ought to be able to scale it!
« Last Edit: December 13, 2012, 03:05:45 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.