Rolls Royce Cresi (sp?)

[Andy_RR]

Does anyone have any knowledge, links, references, information on the post-Merlin/Griffon RR Cresi (sp?). I have heard that there exists a book describing it's development - but nothing appears on Google.

Any leads would be appreciated.

Cheers,

A

[Andy_RR]

now Google works OK!

[henry crun]

First tested in 1941 the Crecy was a V12 liquid cooled sleeve valved two stroke.
At 1593 cu. in. it was a little smaller than the Merlin displacement, and had the blocks spaced at 90 degrees.

It was expected to develop over 3000hp but it suffered from severe piston overheating, and Hooker concluded it could never compete with 4 strokes in output per unit piston area.

Source: World Encyclopaedia of Aero Engines by Bill Gunston.

[Brian Abraham]

Andy – “Allied Aircraft Piston Engines of World War II” by Graham White has a couple of pages on the Crecy, regarded as without doubt the most radical and promising of all the Rolls Royce piston engines. It notes that while one thinks of a two stroke as a simple engine, the Crecy was nothing of the sort. It was very complex, advanced engine featuring direct fuel injection into the stratified charge combustion chamber and scavenged by means of sleeve valves and high blower pressures.
Rolls Royce built several full size engines with two families in mind. One for fighters with open exhaust stacks to provide considerable jet thrust and a transport version with a power recovery turbine. As Henry says it had a capacity of 1593 cu in, bore 5.1 in, stroke 6.5 inches. The engine suffered high crankshaft torsional vibration which played havoc with the supercharger drive and necessitated a free wheel in the drive chain to dampen the worst of the vibration. Piston cooling was a major concern and various schemes of spraying oil to the under side of the piston were tried. Because of development difficulties it is doubtful that more than 1700 HP was ever achieved under test.
Rolls Royce abandoned development in December 1945 due to the overwhelming superiority of the emerging gas turbines. Sir Harry Ricardo who was infatuated with the Crecy continued development at his own expense and tested it in single cylinder form at his laboratory in Shoreham. He finally achieved a BMEP of 325, 219 horsepower/litre, running at 37 psi boost (104 inches Hg) and augmented with ADI. The lack of fuel pump displacement limited achievement of higher ratings. Sleeve valves failures were a problem however.

[Dick Whittingham]

Warning. Thread creep

RR did develop and fly a sleeve valve engine, the Eagle. This was a 24 cylinder flat H, rather like the Sabre. It flew in a prototype Wyvern, before the Wyvern changed to an AS Python.

Two Eagles were at Sinfin in the 1950's driving Derwent compressors to provide air for various test rigs. Even with industrial silencers they made a lovely noise.

Dick

[Brian Abraham]

Details of engine here http://en.wikipedia.org/wiki/Rolls-Royce_Crecy

The history of the Crecy’s development is chronicled in a book, The Rolls-Royce Crecy, by A. Nahum, R. W. Foster-Pegg, and D. Birch, published by the Rolls-Royce Heritage Trust in 1994. Although this book no longer appears on the Rolls-Royce web site, it can still be had by writing to the Rolls-Royce Heritage Trust. A review of the book can be found here (towards the bottom of the page) http://www.enginehistory.org/Reviews/book_reviews_2.htm

[henry crun]

Brian, You mentioning the Rolls-Royce Heritage Trust caused me to browse through my son's bookcase, and there I found "Rolls-Royce Piston Aero Engines, a designer remembers, by A.A. Rubbra".

There is a short article about the Crecy; apparently the original project was for a diesel two stroke but the Air Ministry directed it should be a fuel injection spark ignition engine.

It also quotes Dr. S.G. Hooker describing the 4-stroke engine as one with
"one stroke to produce the power and three strokes to wear it out". :)