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Author Topic: Rolls Royce Vulture  (Read 5139 times)

Offline PMN1

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Rolls Royce Vulture
« on: December 01, 2007, 09:14:37 am »
Presumably the reasoning behind the historical approach to the Vulture was 'we have most of the parts we will need, so the required development time and money will be reduced'.

How would RR have fared if it had decided to use a clean sheet as it did with the later Eagle?

Offline CJGibson

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Re: Rolls Royce Vulture
« Reply #1 on: December 02, 2007, 01:53:47 am »
Quote - "Presumably the reasoning behind the historical approach to the Vulture was 'we have most of the parts we will need, so the required development time and money will be reduced'.

How would RR have fared if it had decided to use a clean sheet as it did with the later Eagle?"
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I'm sure it was a case of "we have the parts, lets join them together" initially, but R-R soon found out that they needed to redesign quite a few of the standard Peregrine components. According to Alec Lumsden's "British Piston Engines and their Aircraft" (a snip at £39.95) one major problem was conrod failure, partly due to having the four big ends of each "row" of cylinders on a single crank pin. Another was the two coolant pumps starving each other of flow with the usual results of poor cooling.

Lumsden reckons the Vulture V was sorted put and would have been a success had it had a chance. Neither the time nor money to give it a chance was available

Saying that, there is a seven month gap in 1942 between Vulture termination and Eagle commencing, so perhaps R-R had a few ponderings on where to go next. Interesting how they came up with the H-layout with sleeve valves for the Eagle.
 
A clean sheet better? Undoubtedly, with the experience they had behind them by 1942. Perhaps R-R had more than enough to keep them busy on the clean sheet department with the Exe and the Crecy at the time they commenced the Vulture in the late 30s. One of Hives' reasons for scrapping the Vulture was to allow engineers to concentrate on other projects.

The perceived benefits of a single 3000hp engine over two 1500hp jobs are clear: less maintenance, single installation, etc etc. So it would be attractive on paper, but experience would prove otherwise and that's how engineering progresses: push a design until it breaks.

Joining two engines into one sounds great, but as Daimler-Benz found out with the DB.610, it's fraught with trouble. Perhaps the French had the right idea of using tandem engines. I sometimes wonder how long it took Volkswagen to bite the bullet and build the W12 engine for the Golf, Phaeton and the Bugatti Veyron. Or perhaps they never looked at a book on the He.177. Then again with 60 years of materials development and experience, such things must now be possible in a standard road car (not that I could ever describe the Veyron as standard).

I'd be interesting in hearing an alternative view from the US as I can't recall a US conjoined-engine project apart from the Chrysler IV-2220 for the XP-47H, which was two V8s in line I believe.

KB

Offline CJGibson

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Re: Rolls Royce Vulture
« Reply #2 on: December 02, 2007, 03:47:00 am »
Just a thought, could the Vulture been Rolls' response to the Fairey P.24, which was two flat-twelves side-by-side? Esch side could operate independently providing twin-engine capability in one installation.

KB

Offline PMN1

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Re: Rolls Royce Vulture
« Reply #3 on: December 02, 2007, 02:57:08 pm »
Just a thought, could the Vulture been Rolls' response to the Fairey P.24, which was two flat-twelves side-by-side? Esch side could operate independently providing twin-engine capability in one installation.

KB

You have reminded me of something that was sent to me a while back regarding the fairey engines

http://www.secretprojects.co.uk/forum/index.php/topic,986.0.html

Offline Schneiderman

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Re: Rolls Royce Vulture
« Reply #4 on: November 21, 2018, 09:11:46 am »
Sorry for dragging this ancient thread back from the dead.

Chris asked about US engines that took a similar approach to the Vulture. I know of one, the Packard 1A-2775, an X engine based on two V-12 V-1500s. It was built for racing purposes and used in the Kirkham-Williams Racer in 1927 and then in the Williams Mercury racer in 1929.  Like the Vulture it suffered from big-end bearing problems, mainly because they were of large diameter and rather narrow.

I do wonder whether there was some other underlying problem with the Vulture. Its direct predecessors, the Goshawk and Peregrine, both suffered development problems and were abandoned early. Is it possible that the given reasons for dropping them; evaporative cooling trouble and installation issues respectively, masked some other, deeper, problems that carried over into the Vulture?

Clearly the pressures on industry resultant on the ever more demanding requirements of the RAF expansion plans caused growing problems but it is staggering the number of high powered engine projects that either failed or stalled in the 1930s.  Armstrong Siddeley failed to produce a single successful 'Dog' engine, Alvis had plans for several types that they subsequently dropped (or were forced to drop), Fairey ditto, and Bristol had its troubles too.
« Last Edit: November 22, 2018, 04:01:29 am by Schneiderman »

Offline Hood

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Re: Rolls Royce Vulture
« Reply #5 on: November 22, 2018, 12:59:58 am »
Its an interesting thought Schneiderman. Certainly no British engine manufacturer seems to have escape some kind of technical woe with their high-powered designs.
Do you feel it might have been a materials problem? Or perhaps lubrication issues? I know there had been a lot of development of coolants and fuels during the 1930s, but was there the same kind of development in lubricants?


Just as an aside, but tangentially related given Chris' post above, when me and Chris were going round Cosford the other week, Chris noticed that the engine blocks of the DB610 on display were stamped as standard DB605s. Proof that even using standard engines in a new mounting and concept doesn't mean success is guaranteed.
« Last Edit: November 22, 2018, 01:02:09 am by Hood »

Offline Schneiderman

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Re: Rolls Royce Vulture
« Reply #6 on: November 22, 2018, 04:08:39 am »
WAY out of my area of knowledge, so I hope others have informed views.  I had not considered lubrication, an interesting thought.
Racing engines developed from standard models in the 1920s tended to fail due to what was usually called carburetter problems, which was almost certainly bad design of intakes and instability in airflow. This was compounded when superchargers were introduced, and it is to Rolls-Royce's credit that they developed a good understanding of airflow management before many others. Is it possible that the rapid increase in engine power in the 1930s through better fuels, higher revs and higher boost had come up against something similar?

Offline Nick Sumner

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Re: Rolls Royce Vulture
« Reply #7 on: November 22, 2018, 05:54:02 am »
Certainly no British engine manufacturer seems to have escape some kind of technical woe with their high-powered designs.

No engine manufacturer anywhere working on high powered designs in this era got a new engine to an acceptable level of development without a long hard struggle. The Americans cancelled all their 'hyper' engines, the German engine builders had to be wrangled by Speer to get them back on topic because of their tendency for engineering digressions of questionable utility (hence the great engine project cull of late 1942), but the Japanese were the worst at junking engine designs that didn't co-operate even though each manufacturer stuck with a narrow range of cylinder sizes. The Peregrine was cancelled because the Merlin had more development potential and Rolls Royce were at full stretch, otherwise it was 'coming along nicely'.

Other 'X' engines

https://oldmachinepress.com/2013/06/16/allison-x-4520-24-cylinder-aircraft-engine/

https://oldmachinepress.com/2018/07/20/daimler-benz-db-604-x-24-aircraft-engine/

https://oldmachinepress.com/2017/01/05/fiat-a-38-a-40-and-a-44-aircraft-engines/

https://oldmachinepress.com/2017/06/05/isotta-fraschini-zeta-x-24-aircraft-engine/

https://oldmachinepress.com/2018/09/05/packard-x-2775-24-cylinder-aircraft-engine/

Be warned, the old machine press site is ludicrously addictive...

Offline Kevin Renner

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Re: Rolls Royce Vulture
« Reply #8 on: November 22, 2018, 04:33:57 pm »
Certainly no British engine manufacturer seems to have escape some kind of technical woe with their high-powered designs.

No engine manufacturer anywhere working on high powered designs in this era got a new engine to an acceptable level of development without a long hard struggle. The Americans cancelled all their 'hyper' engines, the German engine builders had to be wrangled by Speer to get them back on topic because of their tendency for engineering digressions of questionable utility (hence the great engine project cull of late 1942), but the Japanese were the worst at junking engine designs that didn't co-operate even though each manufacturer stuck with a narrow range of cylinder sizes. The Peregrine was cancelled because the Merlin had more development potential and Rolls Royce were at full stretch, otherwise it was 'coming along nicely'.

Other 'X' engines

https://oldmachinepress.com/2013/06/16/allison-x-4520-24-cylinder-aircraft-engine/

https://oldmachinepress.com/2018/07/20/daimler-benz-db-604-x-24-aircraft-engine/

https://oldmachinepress.com/2017/01/05/fiat-a-38-a-40-and-a-44-aircraft-engines/

https://oldmachinepress.com/2017/06/05/isotta-fraschini-zeta-x-24-aircraft-engine/

https://oldmachinepress.com/2018/09/05/packard-x-2775-24-cylinder-aircraft-engine/

Be warned, the old machine press site is ludicrously addictive...

Addictive is a mild description on OMP. The Chrysler 16 cylinder inverted V simply had the reduction gearing located in the center of the crankcase. The main reason is the really long crankshaft. In terms of doubling engines the H layout was most likely better than an X simply because you used two crankshafts so you weren't adding extra loads on the crankpins. The French had a few desgns of H -24 engines. Two Hisso's plus the Arsenal based on Jumo components

Offline Nick Sumner

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Re: Rolls Royce Vulture
« Reply #9 on: November 23, 2018, 04:55:25 am »
The single crankshaft 'X' layout is more elegant in engineering terms in part because for any given displacement the weight of an engine with a single crankshaft tends to be less than that of an engine with two crankshafts.

Offline Kevin Renner

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Re: Rolls Royce Vulture
« Reply #10 on: December 30, 2018, 07:43:02 am »
The X layout may be more elegant and I think probably better than the H in terms of intake manifold design. IMO the best of the doubled engines using an existing V type was the Allison. I suspect a lot of the issues with the failed double engines involved bearing materials

Offline Caravellarella

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Re: Rolls Royce Vulture
« Reply #11 on: December 30, 2018, 08:26:22 am »

Be warned, the old machine press site is ludicrously addictive...

Understatement of the year!  ;D

Terry (Caravellarella)
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