Engine Questions

[GregP]

GDoes anyone have any technical information about the Rolls-Royce EXE engine. I know it had 24 cylinders, but that's about it.

I am also looking for data on the Rolls-Royce Crecy engine. I know it is a 2-stroke, 12-cylinder Vee engine, but do not know the bore and stroke, rated RPM, weight, or specific fuel consumption.

Similar questions for the Saurer YS 2.

Also the Bristol Pelides.

Any information would be appreciated.

[PMN1]

If you can get hold of them then Bill Gunston's books seem to be quite good (though I have heard some people say otherwise).

I have some copies of some of the pages which include the Exe and the Crecey so i'll dig them out and post them, though IIRC they dont describe all the details.

[GregP]

Thanks PMN1!

[Kutscha]

Crecy

bore - 5.1"
stroke - 6.5"
disp - 1593ci/26.1l
power - 3.6hp/^3(219hp/l) @ 37" boost(104" Hg)

It was also a sleeve valve engine.

Two versions were planed. One for fighters with open exhausts for exhaust thrust and one for transport use which used a power recovery turbine to feed power back to the supercharger.(sc not connected to the crankshaft)

Exe

bore - 4.2"
stroke - 4.0"
disp - 1348ci/21.7l
power - 1150hp@4200rpm, potential for 1500hp

ps. Info came from Graham White's engine book. ISBN 1-56091-5-655-9

[PMN1]

The Exe

From Bill Gunston’s World Encyclopedia of Aero Engines ‘ever alert to new technology, RR began research with sleeve-valve cylinders not later than 1933, and in 1934 built a complete sleeve-valve Kestrel. This ran satisfactorily, though it was used to provide design experience and never flew. With the knowledge gained, Rowledge spent 1935 designing the aptly named Exe. This totally new engine was a single crankshaft 90° X-24 with tiny cylinders 4.225 x 4” (1,348 cu in) with sleeve- valves and pressure air-cooling. First run in September 1936, it was initially run at 920hp at 11,000ft but was soon giving 1,200hp with plenty more to come. One of the smoothest and most trouble free engines imaginable, it was intended for Navy aircraft staring with the Barracuda, because of its air-cooling. It was always a low-priority oddball and in the vast expansion of 1938 was cancelled, but it was so popular with Hucknell test pilots they used the Exe-Battle as their ‘hack’ communications aircraft until at least 1943. Exe-type design was never stopped, and the Pennine was planned as a much more powerful (2,500hp) successor for post war civil aviation, only to be overtaken by the gas turbine.

Not sure where I read this but it was cancelled in favour of the Peregrine, Merlin and Vulture, and its cancellation delayed substantial deliveries of the Barracuda by around two years – the RN were expecting around 250 Exe Barracudas in 1941.

The Crecy

From Bill Gunston’s World Encyclopaedia of Aero Engines ‘Least known of the company’s piston engines, because everyone was too busy to write it down at the time, the Crecy was the most advanced 2-stroke aero engine ever built. Sir Harry Riccardo began work in about 1937, testing sleeve-valve cylinders with a clever system of charge stratification from an injector in the head. One feature was the high exhaust energy, making an exhaust turbine desirable. Ricardo’s results justified Derby building a complete engine, and by 1941 the Crecy was on test. A liquid cooled V12, it had cylinders 5.1 x 6.5” (1,593 cu in), a little smaller than the Merlin in displacement and with the blocks spaced at 90°. Project engineer Harry Wood recalled from a distance of 25 years that without a turbine the engine gave 2,000hp at 2,600 rpm, and was expected to reach well over 3,000hp with gas turbine geared to the crankshaft. The Crecy team made extravagant claims for it, but it suffered severe piston overheating and Hooker concluded it could never compete with the 4-strokes in output per unit piston area.

[Groggy]

quote:Originally posted by PMN1

The Exe

From Bill Gunston’s World Encyclopedia of Aero Engines ‘ever alert to new technology, RR began research with sleeve-valve cylinders not later than 1933, and in 1934 built a complete sleeve-valve Kestrel. This ran satisfactorily, though it was used to provide design experience and never flew. With the knowledge gained, Rowledge spent 1935 designing the aptly named Exe. This totally new engine was a single crankshaft 90° X-24 with tiny cylinders 4.225 x 4” (1,348 cu in) with sleeve- valves and pressure air-cooling. First run in September 1936, it was initially run at 920hp at 11,000ft but was soon giving 1,200hp with plenty more to come. One of the smoothest and most trouble free engines imaginable, it was intended for Navy aircraft staring with the Barracuda, because of its air-cooling. It was always a low-priority oddball and in the vast expansion of 1938 was cancelled, but it was so popular with Hucknell test pilots they used the Exe-Battle as their ‘hack’ communications aircraft until at least 1943. Exe-type design was never stopped, and the Pennine was planned as a much more powerful (2,500hp) successor for post war civil aviation, only to be overtaken by the gas turbine.

Not sure where I read this but it was cancelled in favour of the Peregrine, Merlin and Vulture, and its cancellation delayed substantial deliveries of the Barracuda by around two years – the RN were expecting around 250 Exe Barracudas in 1941.

The Crecy

From Bill Gunston’s World Encyclopaedia of Aero Engines ‘Least known of the company’s piston engines, because everyone was too busy to write it down at the time, the Crecy was the most advanced 2-stroke aero engine ever built. Sir Harry Riccardo began work in about 1937, testing sleeve-valve cylinders with a clever system of charge stratification from an injector in the head. One feature was the high exhaust energy, making an exhaust turbine desirable. Ricardo’s results justified Derby building a complete engine, and by 1941 the Crecy was on test. A liquid cooled V12, it had cylinders 5.1 x 6.5” (1,593 cu in), a little smaller than the Merlin in displacement and with the blocks spaced at 90°. Project engineer Harry Wood recalled from a distance of 25 years that without a turbine the engine gave 2,000hp at 2,600 rpm, and was expected to reach well over 3,000hp with gas turbine geared to the crankshaft. The Crecy team made extravagant claims for it, but it suffered severe piston overheating and Hooker concluded it could never compete with the 4-strokes in output per unit piston area.







The RR Heritage series is a fantastic source.

THE ROLLS-ROYCE CRECY
A Nahum RW Forester-Pegg D Birch 1994 (137 pages, 59 photographs/ illustrations)

'A detailed account of the design and development of what was probably the most revolutionary piston aero engine built by Rolls-Royce.'

Price for Members: £6.00
Price for Non Members: £9.00

The Exe powered Battle would cruise faster than the Merlin version on about 5L less. (thinks would that have made it a good choice for the Whirlwind)

I think i read that on one occasion being air cooled when one of the heads came of it still carried on, can any one confirm??

[i16stealth]

I'm adding a question :)

Could someone give me the characteristics of Wright-Cyclone SGR-1820 F-54?

[Mark J]

Hi Groggy
The aircooled 2 strokes and sleeve valve engines have their 'valving' in the cylinder walls, not up on the heads like a conventional poppet valve engine. So, if a cylinder looses a head, then that cylinders piston will still keep moving up and down in the bore, pushed by the crank. With no valve gear to get fouled in, there was no reason for the engine to not continue running although it would be at a slightly reduced power out-put. I believe a few Bristol sleeve valve engines in the RAF bombers returned with whole cylinders shot off and still running!
Loosing a head on a poppet valve engine could mean almost instant destruction, if the valves/pushrods etc got tangled with the piston.
cheers

[tenmmike]

nice sleeve valve engine site.
http://www-g.eng.cam.ac.uk/125/achievements/ricardo/

[Groggy]

quote:Originally posted by tenmmike

nice sleeve valve engine site.
http://www-g.eng.cam.ac.uk/125/achievements/ricardo/


MarkJ Good points, thanks its jogged my memory.

Tenmmike, super site, thanks.

Greg P. ALVIS Ltd, Coventry, quality car firm, Licensed, then improved Gnome-Rhone design.
ALVIS PELIDES, 1000hp, 1936, 14-cylinder air cooled two row radial poppet-valveFuel 87 OctaneBore/stroke 5.75x6.5 in. Vol 2359.8 cu in.(146 x 165mm. Vol.38.7 litre) Compression ratio 5.5:1.
Passed 50 hour AM civil type test, in 1937. only 15 built.

Thinks- larger than Hercules with poppet-valves, good basic design, potential for 1500hp to about 2000hp given 100octane fuel and possible production by 1939?
What were the outputs for similar American,French etc poppet valve radials of the period?

[PMN1]

I've only seen pictures of a free standing Exe engine and none of the Pennine.

Does anyone have any pictures of an Exe or Pennine fitted aircraft to see what thye would look like with that engine?

[ChrisMcD]

This looks like the Exe prototype - no way is that a turboprop

http://1000aircraftphotos.com/APS/2952.jpg

How do you past photos?

[GregP]

Chris McD,

That aircraft is the prototype Westland Wyvern. The engine is a Rolls Royce Eagle 22. It produced 3,450 HP and was faster than the Turboprop version.

[Groggy]

quote:Originally posted by GregP

Chris McD,

That aircraft is the prototype Westland Wyvern. The engine is a Rolls Royce Eagle 22. It produced 3,450 HP and was faster than the Turboprop version.

Hi,
You can still see both aircraft and engine at the Fleet Air Arm Museum,

[ChrisMcD]

Hi Guys,

Sorry, got my Fleet Air Arm planes muddled - the Albacore was supposed to get the Exe!

Although the fact that it ended up needing a Griffon makes one wonder how it would have made out with the Exe.

[GregP]

Thank you everyone!

I appreciate the help.

[Nick Sumner]

PMN1, Page 160 & 161 of British Secret Projects have drawings of Exe engined Spearfish developments which give an idea of the cowling profile. I suspect the Pennine might have been similar.

[Groggy]

quote:Originally posted by Nick Sumner

PMN1, Page 160 & 161 of British Secret Projects have drawings of Exe engined Spearfish developments which give an idea of the cowling profile. I suspect the Pennine might have been similar.

Hi Nick,
I thought the same untill one looks at the drawings /photographs of the respective motors.
For the Exe the gears vertically offset the airscrew from the central axis to give greater ground/deck clearance.
The Pennine had epicyclic gears symetrical about the engines major axis----may be with fan?
My flat roof has let water! 15 bags of rubbish later and the majority of books/papers etc boxed up.
there fore difficult to verify about fan can any one else help in the mean time.