Rolls-Royce Crecy
Encyclopedia
The Rolls-Royce Crecy was an unusual British experimental two-stroke, 90-degree, V12
, liquid-cooled aero-engine
of 1,536 cu.in
(26 L
) capacity
, featuring sleeve valve
s and direct petrol injection
. Developed between 1941 and 1945 it was the most advanced two-stroke aero-engine ever to be built.
The engine was named after the Battle of Crécy
, battles being the intended names for future Rolls-Royce two-stroke engines, however no further engines of this type were built.
The Crecy was intended to power the Supermarine Spitfire
after flight testing in a converted Hawker Henley
, but neither aircraft type flew with this engine fitted. The project was cancelled in December 1945 as the progress of jet engine
development overtook that of the Crecy and replaced the need for this engine.
, Chairman of the Aeronautical Research Committee
(ARC), was a proponent of a high-powered "sprint" engine for fighter aircraft and had foreseen the need for such a powerplant as early as 1935 with the threat of German air power
looming. It has been suggested that Tizard influenced his personal friend Harry Ricardo
to develop what eventually became known as the Rolls-Royce
Crecy. The idea was officially discussed for the first time at an engine sub-committee meeting in December 1935.
Previous experience gained between 1927 and 1930 using two converted Rolls-Royce Kestrel
engines through an Air Ministry contract had proven the worth of further research into a two-stroke sleeve-valved design. Both these engines had initially been converted to diesel
sleeve-valved operation with a lower power output than the original design being noted along with increased mechanical failures, although one converted Kestrel was subsequently used successfully by Captain George Eyston
in a land-speed record car named Speed of the Wind
. The second engine was further converted to petrol injection which then gave a marked power increase over the standard Kestrel.
Single-cylinder development began in 1937 under project engineer Harry Wood using a test unit designed by Ricardo. Although originally conceived as a compression ignition engine, by the time Rolls-Royce started serious development, in conjunction with the Ricardo company
, the decision had been taken by the Air Ministry
to revert to a more conventional spark-ignition layout, although still retaining petrol-injection.
7:1 and weight 1,900 lb (862 kg). The firing angle
was 30 degrees BTDC
, and 15 lbf/in² (100 kPa) supercharger
boost was typical. In bench-testing it produced 1400 hp; however, there were problems with vibration and the cooling of the pistons and sleeves. The thrust produced by the exceptionally loud two-stroke exhaust was estimated as being equivalent to a 30% increase in power at the propeller
on top of the rated output of the engine. The power of the engine was interesting in its own right, but the additional exhaust thrust at high- speed and altitude could have made it a useful stop gap between engines such as the Rolls-Royce Merlin
and anticipated jet engines. Serial numbers were even, Rolls-Royce practice being to have even numbers for clockwise
rotating engines when viewed from the front.
– the open end uncovered the exhaust ports high in the cylinder wall at the bottom of the sleeves' stroke, leaving the ports cut into the sleeve to handle the incoming charge only. They had a stroke of 30% of the piston travel at 1.950 in (49.5 mm) and operated 15 degrees in advance of the crankshaft
. The Crecy sleeve valves were of similar construction but differed in their operation compared to the rotary
sleeve valve design that was pioneered by Roy Fedden
, and used successfully for the first time in an aircraft engine, the Bristol Perseus
, in 1932.
was used where the fuel was injected into a bulb-like extension of the combustion chamber
where the twin spark plug
s ignited the rich mixture. Operable air-fuel ratio
s of from 15 to 23:1 were available to govern the power produced between maximum and 60%. The rich mixture maintained near the spark plugs reduced detonation
allowing higher compression ratios or supercharger boost. Supercharger throttling was used as well to achieve idling. The supercharger throttles were novel vortex types, varying the effective angle of attack
of the impeller blades from 60 to 30 degrees. This reduced the power required to drive the supercharger when throttled, and hence fuel consumption at cruising power.
Later testing involved the use of an exhaust turbine
which was a half-scale version of that used in the Whittle W.1
turbojet, the first British jet engine to fly. Unlike a conventional turbocharger
the turbine was coupled to the engine's accessory driveshaft and acted as a power recovery device
. It was thought that using the turbine would lower fuel consumption allowing the engine to be used in larger transport aircraft. This was confirmed during testing however failures due to severe overheating and drive shaft fractures were experienced.
Data from:
, L3385
which was delivered to Hucknall
for conversion on 28 March 1943. This aircraft remained at Hucknall until 11 September 1945 when it was scrapped without ever having the engine fitted.
, P7674 had been delivered to Hucknall and was fitted with a Crecy mock-up
to enable cowling
drawings and system details to be designed. It had also been agreed that the first production Spitfire Mk III would be delivered to Hucknall in early 1942 minus its Merlin
engine for fitment of an airworthy Crecy; this delivery did not occur however. A Royal Aircraft Establishment
report (No. E.3932) of March 1942 estimated the performance of the Spitfire fitted with a Crecy engine and also compared this to a Griffon 61
-powered variant of the type. The report stated that the Crecy's maximum power output would be too much for the Spitfire airframe but that a derated version would have considerable performance gains over the Griffon-powered fighter.
V12 engine
A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually but not always at a 60° angle to each other, with all 12 pistons driving a common crankshaft....
, liquid-cooled aero-engine
Aircraft engine
An aircraft engine is the component of the propulsion system for an aircraft that generates mechanical power. Aircraft engines are almost always either lightweight piston engines or gas turbines...
of 1,536 cu.in
Cubic inch
The cubic inch is a unit of measurement for volume in the Imperial units and United States customary units systems. It is the volume of a cube with each of its 3 sides being one inch long....
(26 L
Litre
pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
) capacity
Engine displacement
Engine displacement is the volume swept by all the pistons inside the cylinders of an internal combustion engine in a single movement from top dead centre to bottom dead centre . It is commonly specified in cubic centimeters , litres , or cubic inches...
, featuring sleeve valve
Sleeve valve
The sleeve valve is a type of valve mechanism for piston engines, distinct from the usual poppet valve. Sleeve-valve engines saw use in a number of pre-World War II luxury cars and in USA in the Willys-Knight car and light truck...
s and direct petrol injection
Fuel injection
Fuel injection is a system for admitting fuel into an internal combustion engine. It has become the primary fuel delivery system used in automotive petrol engines, having almost completely replaced carburetors in the late 1980s....
. Developed between 1941 and 1945 it was the most advanced two-stroke aero-engine ever to be built.
The engine was named after the Battle of Crécy
Battle of Crécy
The Battle of Crécy took place on 26 August 1346 near Crécy in northern France, and was one of the most important battles of the Hundred Years' War...
, battles being the intended names for future Rolls-Royce two-stroke engines, however no further engines of this type were built.
The Crecy was intended to power the Supermarine Spitfire
Supermarine Spitfire
The Supermarine Spitfire is a British single-seat fighter aircraft that was used by the Royal Air Force and many other Allied countries throughout the Second World War. The Spitfire continued to be used as a front line fighter and in secondary roles into the 1950s...
after flight testing in a converted Hawker Henley
Hawker Henley
-See also:-References:NotesBibliography* Cooper, H.J.,O.G. Thetford and C.B. Maycock. Aircraft of the Fighting Powers - Volume II. Leicester, UK: Harborough Publishing, 1942....
, but neither aircraft type flew with this engine fitted. The project was cancelled in December 1945 as the progress of jet engine
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
development overtook that of the Crecy and replaced the need for this engine.
Design and development
Sir Henry TizardHenry Tizard
Sir Henry Thomas Tizard FRS was an English chemist and inventor and past Rector of Imperial College....
, Chairman of the Aeronautical Research Committee
Aeronautical Research Committee
The Aeronautical Research Committee was a UK government committee established in 1919 in order to coordinate aeronautical research and education following World War I...
(ARC), was a proponent of a high-powered "sprint" engine for fighter aircraft and had foreseen the need for such a powerplant as early as 1935 with the threat of German air power
Events preceding World War II in Europe
The events preceding World War II in Europe are closely tied to the rise of fascism, especially in Nazi Germany.-Aftermath of World War I:World War II is generally viewed as having its roots in the aftermath of the First World War...
looming. It has been suggested that Tizard influenced his personal friend Harry Ricardo
Harry Ricardo
Sir Harry Ricardo was one of the foremost engine designers and researchers in the early years of the development of the internal combustion engine....
to develop what eventually became known as the Rolls-Royce
Rolls-Royce Limited
Rolls-Royce Limited was a renowned British car and, from 1914 on, aero-engine manufacturing company founded by Charles Stewart Rolls and Henry Royce on 15 March 1906 as the result of a partnership formed in 1904....
Crecy. The idea was officially discussed for the first time at an engine sub-committee meeting in December 1935.
Previous experience gained between 1927 and 1930 using two converted Rolls-Royce Kestrel
Rolls-Royce Kestrel
|-See also:-Bibliography:* Erfurth, Helmut. Junkers Ju 87 . Bonn, Germany: Bernard & Graefe Verlag, 2004. ISBN 1-85780-186-5....
engines through an Air Ministry contract had proven the worth of further research into a two-stroke sleeve-valved design. Both these engines had initially been converted to diesel
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
sleeve-valved operation with a lower power output than the original design being noted along with increased mechanical failures, although one converted Kestrel was subsequently used successfully by Captain George Eyston
George Eyston
- References :*...
in a land-speed record car named Speed of the Wind
Speed of the Wind
Speed of the Wind was a record-breaking car of the 1930s, built for and driven by Captain George Eyston.The car was designed by Eyston and E A D Eldridge, then built by the father of Tom Delaney It was powered by an unsupercharged version of the V-12 Rolls-Royce Kestrel aero engine...
. The second engine was further converted to petrol injection which then gave a marked power increase over the standard Kestrel.
Single-cylinder development began in 1937 under project engineer Harry Wood using a test unit designed by Ricardo. Although originally conceived as a compression ignition engine, by the time Rolls-Royce started serious development, in conjunction with the Ricardo company
Ricardo plc
Ricardo plc is a British publicly listed company named after its founder, Sir Harry Ricardo and founded on 30 June 1927 in Shoreham-by-Sea, West Sussex. The company is a leading global multi-industry engineering provider of technology, product innovation and strategic consulting...
, the decision had been taken by the Air Ministry
Air Ministry
The Air Ministry was a department of the British Government with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964...
to revert to a more conventional spark-ignition layout, although still retaining petrol-injection.
Name origin
The engine was named after the Battle of Crécy, battles being the chosen theme for Rolls-Royce two-stroke aero engines. There were however no subsequent Rolls Royce engines of this type, and jet engines were subsequently given the names of rivers.Technical description
The first complete V12 engine was built in 1941, designed by a team led by Harry Wood with Eddie Gass as the Chief Designer. Bore was 5.1 in (129.5 mm), stroke 6.5 in (165.1 mm), compression ratioCompression ratio
The 'compression ratio' of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity...
7:1 and weight 1,900 lb (862 kg). The firing angle
Ignition timing
Ignition timing, in a spark ignition internal combustion engine , is the process of setting the angle relative to piston position and crankshaft angular velocity that a spark will occur in the combustion chamber near the end of the compression stroke...
was 30 degrees BTDC
Dead centre
In a reciprocating engine, the dead centre is the position of a piston in which it is farthest from, or nearest to, the crankshaft. The former is known as top dead centre while the latter is known as bottom dead centre ....
, and 15 lbf/in² (100 kPa) supercharger
Supercharger
A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
boost was typical. In bench-testing it produced 1400 hp; however, there were problems with vibration and the cooling of the pistons and sleeves. The thrust produced by the exceptionally loud two-stroke exhaust was estimated as being equivalent to a 30% increase in power at the propeller
Propeller (aircraft)
Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...
on top of the rated output of the engine. The power of the engine was interesting in its own right, but the additional exhaust thrust at high- speed and altitude could have made it a useful stop gap between engines such as the Rolls-Royce Merlin
Rolls-Royce Merlin
The Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...
and anticipated jet engines. Serial numbers were even, Rolls-Royce practice being to have even numbers for clockwise
Clockwise
Circular motion can occur in two possible directions. A clockwise motion is one that proceeds in the same direction as a clock's hands: from the top to the right, then down and then to the left, and back to the top...
rotating engines when viewed from the front.
Sleeve valves
The reciprocating sleeve valves were open-ended rather than sealing in a Junk headJunk head
A junk head is a form of piston engine cylinder head, where the head is formed by a dummy piston mounted inside the top of the cylinder. In most other engine designs, the cylinder head is mounted on top of the cylinder block. This form has also been termed a "poultice head".It is obviously...
– the open end uncovered the exhaust ports high in the cylinder wall at the bottom of the sleeves' stroke, leaving the ports cut into the sleeve to handle the incoming charge only. They had a stroke of 30% of the piston travel at 1.950 in (49.5 mm) and operated 15 degrees in advance of the crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...
. The Crecy sleeve valves were of similar construction but differed in their operation compared to the rotary
Rotation
A rotation is a circular movement of an object around a center of rotation. A three-dimensional object rotates always around an imaginary line called a rotation axis. If the axis is within the body, and passes through its center of mass the body is said to rotate upon itself, or spin. A rotation...
sleeve valve design that was pioneered by Roy Fedden
Roy Fedden
Sir Alfred Hubert Roy Fedden MBE was an engineer who designed most of Bristol Engine Company's successful aircraft engine designs.-Early life:...
, and used successfully for the first time in an aircraft engine, the Bristol Perseus
Bristol Perseus
|-See also:-Bibliography:* Bridgman, L, Jane's Fighting Aircraft of World War II. Crescent . ISBN 0-517-67964-7* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9...
, in 1932.
Supercharging and exhaust turbine
Unlike most two-stroke engines, supercharging was used rather than crankcase compression to force the charge into the cylinder – this also allowed for a conventional oil lubrication system instead of the total-loss type found in many two-stroke engines. Stratified chargeStratified charge engine
In a stratified charge engine, the fuel is injected into the cylinder just before ignition. This allows for higher compression ratios without "knock," and leaner air/fuel mixtures than in conventional internal combustion engines....
was used where the fuel was injected into a bulb-like extension of the combustion chamber
Combustion chamber
A combustion chamber is the part of an engine in which fuel is burned.-Internal combustion engine:The hot gases produced by the combustion occupy a far greater volume than the original fuel, thus creating an increase in pressure within the limited volume of the chamber...
where the twin spark plug
Spark plug
A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed fuels such as aerosol, gasoline, ethanol, and liquefied petroleum gas by means of an electric spark.Spark plugs have an insulated central electrode which is connected by...
s ignited the rich mixture. Operable air-fuel ratio
Air-fuel ratio
Air–fuel ratio is the mass ratio of air to fuel present in an internal combustion engine. If exactly enough air is provided to completely burn all of the fuel, the ratio is known as the stoichiometric mixture, often abbreviated to stoich...
s of from 15 to 23:1 were available to govern the power produced between maximum and 60%. The rich mixture maintained near the spark plugs reduced detonation
Engine knocking
Knocking in spark-ignition internal combustion engines occurs when combustion of the air/fuel mixture in the cylinder starts off correctly in response to ignition by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.The...
allowing higher compression ratios or supercharger boost. Supercharger throttling was used as well to achieve idling. The supercharger throttles were novel vortex types, varying the effective angle of attack
Angle of attack
Angle of attack is a term used in fluid dynamics to describe the angle between a reference line on a lifting body and the vector representing the relative motion between the lifting body and the fluid through which it is moving...
of the impeller blades from 60 to 30 degrees. This reduced the power required to drive the supercharger when throttled, and hence fuel consumption at cruising power.
Later testing involved the use of an exhaust turbine
Turbine
A turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...
which was a half-scale version of that used in the Whittle W.1
Power Jets
Power Jets Ltd was a United Kingdom company set up by Frank Whittle for the purpose of designing and manufacturing jet engines.-History:Founded on January 27, 1936, the company consisted of Whittle, Rolf Dudley-Williams, James Collingwood Tinling, and Lancelot Law Whyte of investment bankers O T...
turbojet, the first British jet engine to fly. Unlike a conventional turbocharger
Turbocharger
A turbocharger, or turbo , from the Greek "τύρβη" is a centrifugal compressor powered by a turbine that is driven by an engine's exhaust gases. Its benefit lies with the compressor increasing the mass of air entering the engine , thereby resulting in greater performance...
the turbine was coupled to the engine's accessory driveshaft and acted as a power recovery device
Turbo-compound engine
A turbo-compound engine is a reciprocating engine that employs a blowdown turbine to recover energy from the exhaust gases. The turbine is usually mechanically connected to the crankshaft but electric and hydraulic systems have been investigated as well. The turbine increases the output of the...
. It was thought that using the turbine would lower fuel consumption allowing the engine to be used in larger transport aircraft. This was confirmed during testing however failures due to severe overheating and drive shaft fractures were experienced.
Test summary table
The following table summarises the test running programme, hours run, and highlights some of the failures experienced.Data from:
| Engine | Date | Notes | Hours run |
|---|---|---|---|
| Crecy 2 | 11 April 1941 | First run. One-piece cylinder block/head. Testing stopped due to piston failure. | 69 |
| October 1942 – December 1942 |
Three rebuilds during this period, testing stopped after 35 hours due to piston seizure. | 67 | |
| February 1943 – July 1943 |
Converted to Mk II configuration (separate cylinder heads), three rebuilds during this period. Air Ministry acceptance test passed. | 38 | |
| March 1944 – July 1944 |
Five rebuilds during this period. Equal length injector pipes fitted, modified supercharger drive. Two failures, sleeve valve seizure and supercharger drive failure. | 82 | |
| August 1944 – November 1944 |
Successful type test passed (112 hours). Post run inspection revealed cracked big-end Connecting rod In a reciprocating piston engine, the connecting rod or conrod connects the piston to the crank or crankshaft. Together with the crank, they form a simple mechanism that converts linear motion into rotating motion.... bearings, pistons, reduction gear housing and sleeve valve eccentric drive bearing. |
150 | |
| March 1945 – April 1945 |
Attempted endurance test, piston failure after 27 hours. Two rebuilds during this period. | 49 |
|
| Crecy 4 | November 1941 | No report available. | 55 |
| July 1942 – August 1942 |
Three rebuilds, successful 50-hour test, second 50-hour test abandoned after cylinder block failure due to cracking. | 80 | |
| September 1942 – October 1942 |
Two rebuilds. Completed 25-hour test successfully, second test halted after four hours running due to sleeve valve failure. | 55 |
|
| Crecy 6 | July 1943 – February 1944 |
First engine built as Mk II. Eight rebuilds during this period, failures included supercharger drive failure and sleeve valve eccentric drive bolt fracture. | 126 |
| May 1944 – September 1944 |
Four rebuilds. Supercharger flexible drive failure and sleeve valve seizure. | 93 | |
| November 1944 – February 1945 |
Three rebuilds, main bearing failure, piston failure. | 128 | |
| June 1945 – August 1945 |
One rebuild, endurance test halted after 95 hours due to sleeve valve drive failure, 40 hours run with a propeller fitted. | 132 |
|
| Crecy 8 | September 1943 – March 1944 |
Eight rebuilds, endurance test successfully completed. | 207 |
| April 1944 | Supercharger drive failure. | 73 | |
| June 1944 – September 1944 |
Five rebuilds, no failures reported. | 32 | |
| October 1944 – December 1945 |
Two rebuilds, piston failure, engine fitted with exhaust turbine. | 22 |
|
| Crecy 10 | August 1944 – February 1945 |
Six rebuilds, melted inlet manifold after seven hours, sleeve valve seizure after a further four hours. Two injector pump failures. | 53 |
| March 1945 – June 1945 |
One rebuild, piston failure. | 30 | |
| July 1945 – September 1945 |
Two rebuilds, exhaust turbine fitted, some running without supercharger. Sleeve valve and supercharger drive failure. | 82 |
|
| Crecy 12 | January 1945 – October 1945 |
Four rebuilds, exhaust turbine fitted. Turbine failure, piston failure and sleeve valve drive failure. | (Total hours: 67) |
Project cancellation
The progress of jet engine development overtook that of the Crecy and replaced the need for this engine. As a result the project was cancelled in December 1945 at which point only six complete examples had been built, however an additional eight V-twins were built during the project. Crecy s/n 10 achieved 1798 hp on 21 December 1944 which after adjustment for the inclusion of an exhaust turbine would have equated to 2500 hp. Subsequent single-cylinder tests achieved the equivalent of 5000 bhp for the complete engine. By June 1945 a total of 1,060 hours had been run on the V12 engines with a further 8,600 hours of testing on the V-twins. The fate of the six Crecy engines remains unknown.Applications (intended)
Hawker Henley
If the Crecy had flown it would have done so using a Hawker HenleyHawker Henley
-See also:-References:NotesBibliography* Cooper, H.J.,O.G. Thetford and C.B. Maycock. Aircraft of the Fighting Powers - Volume II. Leicester, UK: Harborough Publishing, 1942....
, L3385
United Kingdom military aircraft serials
In the United Kingdom to identify individual aircraft, all military aircraft are allocated and display a unique serial number. A unified serial number system, maintained by the Air Ministry , and its successor the Ministry of Defence , is used for aircraft operated by the Royal Air Force , Fleet...
which was delivered to Hucknall
Hucknall Airfield
Formerly RAF Hucknall, Hucknall Airfield is located north northwest of Nottingham, Nottinghamshire, England.Hucknall has been in continuous use as an airfield since 1916. Formerly RAF Hucknall, it featured in the film The One That Got Away...
for conversion on 28 March 1943. This aircraft remained at Hucknall until 11 September 1945 when it was scrapped without ever having the engine fitted.
Supermarine Spitfire
Two years prior to the Hawker Henley's arrival (Summer 1941) a Supermarine Spitfire Mk IISupermarine Spitfire
The Supermarine Spitfire is a British single-seat fighter aircraft that was used by the Royal Air Force and many other Allied countries throughout the Second World War. The Spitfire continued to be used as a front line fighter and in secondary roles into the 1950s...
, P7674 had been delivered to Hucknall and was fitted with a Crecy mock-up
Mockup
In manufacturing and design, a mockup, or mock-up, is a scale or full-size model of a design or device, used for teaching, demonstration, design evaluation, promotion, and other purposes...
to enable cowling
Cowling
A cowling is the covering of a vehicle's engine, most often found on automobiles and aircraft.A cowling may be used:* for drag reduction* for engine cooling by directing airflow* as an air intake for jet engines* for decorative purposes...
drawings and system details to be designed. It had also been agreed that the first production Spitfire Mk III would be delivered to Hucknall in early 1942 minus its Merlin
Rolls-Royce Merlin
The Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...
engine for fitment of an airworthy Crecy; this delivery did not occur however. A Royal Aircraft Establishment
Royal Aircraft Establishment
The Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...
report (No. E.3932) of March 1942 estimated the performance of the Spitfire fitted with a Crecy engine and also compared this to a Griffon 61
Rolls-Royce Griffon
The Rolls-Royce Griffon is a British 37-litre capacity, 60-degree V-12, liquid-cooled aero engine designed and built by Rolls-Royce Limited...
-powered variant of the type. The report stated that the Crecy's maximum power output would be too much for the Spitfire airframe but that a derated version would have considerable performance gains over the Griffon-powered fighter.
