The Rolls-Royce Eagle Mk XXII is a British 24-cylinder,

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 the United States in the Willys-Knight car and light truck. T ...

, H-block aero engine of 46

litre The litre (international spelling) or liter (American English spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metre (m3 ...

(2,807

cubic inch The cubic inch (symbol in3) is a unit of volume in the Imperial units and United States customary units systems. It is the volume of a cube with each of its three dimensions (length, width, and height) being one inch long which is equivalent to ...

es)

displacement Displacement may refer to: Physical sciences Mathematics and Physics *Displacement (geometry), is the difference between the final and initial position of a point trajectory (for instance, the center of mass of a moving object). The actual path ...

. It was designed and built in the early-1940s by Rolls-Royce Limited and first ran in 1944. It was liquid-cooled, of flat H configuration with two crankshafts and was capable of 3,200

horsepower Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are th ...

(2,387 kW) at 18 psi boost.

Design and development

The Rolls-Royce design team realised that producing a scaled-up version of their Griffon

V-12 engine A V12 engine is a twelve- cylinder piston engine where two banks of six cylinders are arranged in a V configuration around a common crankshaft. V12 engines are more common than V10 engines. However, they are less common than V8 engines. The fi ...

would lead to excessively large

combustion chamber A combustion chamber is part of an internal combustion engine in which the fuel/air mix is burned. For steam engines, the term has also been used for an extension of the firebox which is used to allow a more complete combustion process. Intern ...

s and problems with

detonation Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with ...

.Rubbra 1990, p. 91. The team concluded that a larger number of small cylinders would be the answer and considered an X-24 design. This layout had previously caused unreliability with the

Rolls-Royce Vulture The Rolls-Royce Vulture was a British aero engine developed shortly before World War II that was designed and built by Rolls-Royce Limited. The Vulture used the unusual " X-24" configuration, whereby four cylinder blocks derived from the Ro ...

due to the need to fasten four

connecting rod A connecting rod, also called a 'con rod', is the part of a piston engine which connects the piston to the crankshaft. Together with the crank, the connecting rod converts the reciprocating motion of the piston into the rotation of the cranksha ...

s in a complicated arrangement to a common

big end Big or BIG may refer to: * Big, of great size or degree Film and television * ''Big'' (film), a 1988 fantasy-comedy film starring Tom Hanks * ''Big!'', a Discovery Channel television show * ''Richard Hammond's Big'', a television show presente ...

bearing. The designers finally settled on an 'H' layout with two crankshafts and 'blade and fork' connecting rod attachments, the crankshafts being connected through the

propeller speed reduction unit A propeller speed reduction unit is a gearbox or a belt and pulley device used to reduce the output revolutions per minute (rpm) from the higher input rpm of the powerplant.Gunston 2006, p. 82. This allows the use of small displacement internal ...

. The new engine followed the layout of the

Napier Sabre The Napier Sabre is a British H-24-cylinder, liquid-cooled, sleeve valve, piston aero engine, designed by Major Frank Halford and built by D. Napier & Son during World War II. The engine evolved to become one of the most powerful inline pi ...

and similarly used

s but with a simplified drive system. A two-speed, two-stage

supercharger In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement. The current categorisation is that a supercharger is a form of forced indu ...

and

intercooler An intercooler is a heat exchanger used to cool a gas after compression. Often found in turbocharged engines, intercoolers are also used in air compressors, air conditioners, refrigeration and gas turbines. Internal combustion engines ...

were used to compress then cool the air-fuel mixture, following Griffon and

Merlin Merlin ( cy, Myrddin, kw, Marzhin, br, Merzhin) is a mythical figure prominently featured in the legend of King Arthur and best known as a mage, with several other main roles. His usual depiction, based on an amalgamation of historic and le ...

practice. Starting was by

Coffman starter The Coffman engine starter (also known as a "shotgun starter") was a starting system used on many piston engines in aircraft and armored vehicles of the 1930s and 1940s. It used a cordite cartridge to move a piston, which cranked the engine. The C ...

. An auxiliary shaft driven by the lower crankshaft operated the main coolant pump, intercooler coolant pump, pressure and scavenge oil pumps and a

fuel injection Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All com ...

pump.

Piston ring A piston ring is a metallic split ring that is attached to the outer diameter of a piston in an internal combustion engine or steam engine. The main functions of piston rings in engines are: # Sealing the combustion chamber so that there is mini ...

failures and

cylinder head In an internal combustion engine, the cylinder head (often abbreviated to simply "head") sits above the cylinder (engine), cylinders and forms the roof of the combustion chamber. In sidevalve engines, the head is a simple sheet of metal; whereas ...

sealing problems were experienced during early flight testing.

Applications

The Eagle was never fitted to a production front-line fighter, as it was overshadowed by a new wave of

turbojet engine The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and ...

s, such as the

Rolls-Royce Derwent The Rolls-Royce RB.37 Derwent is a 1940s British centrifugal compressor turbojet engine, the second Rolls-Royce jet engine to enter production. It was an improved version of the Rolls-Royce Welland, which itself was a renamed version of Fran ...

and

turboprop A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. ...

s such as the

Dart Dart or DART may refer to: * Dart, the equipment in the game of darts Arts, entertainment and media * Dart (comics), an Image Comics superhero * Dart, a character from ''G.I. Joe'' * Dart, a ''Thomas & Friends'' railway engine character * D ...

and

Armstrong Siddeley Python The Armstrong Siddeley Python was an early British turboprop engine designed and built by the Armstrong Siddeley company in the mid-1940s. Its main use was in the Westland Wyvern, a carrier-based heavy fighter. The prototypes had used the Roll ...

. Fifteen Eagle 22s were produced to power prototypes of the Westland Wyvern fighter/torpedo bomber because of delay in the development of the Python.

Variants

46H Eagle I :(1944) -

Compression ratio The compression ratio is the ratio between the volume of the cylinder and combustion chamber in an internal combustion engine at their maximum and minimum values. A fundamental specification for such engines, it is measured two ways: the stat ...

6.5:1. 46H Eagle II :(1944) - Modified Eagle I. 46H Eagle (20 srs) 22 :(1946-1949) - Increased compression ratio (7:1), 3,500 hp at 3,500 rpm and 28 lb boost. Fifteen engines produced at the

Derby Derby ( ) is a city and unitary authority area in Derbyshire, England. It lies on the banks of the River Derwent in the south of Derbyshire, which is in the East Midlands Region. It was traditionally the county town of Derbyshire. Derby gain ...

Rolls-Royce factory. First flown in a Westland Wyvern on 16 December 1946.

Engines on display

*An Eagle 22 with some of the cowling panels removed to display the engine can be seen fitted to Westland Wyvern TF1, ''VR137'', at the

Fleet Air Arm Museum The Fleet Air Arm Museum is devoted to the history of British naval aviation. It has an extensive collection of military and civilian aircraft, aero engines, models of aircraft and Royal Navy ships (especially aircraft carriers), and paintin ...

, RNAS Yeovilton. This pre-production aircraft never flew.Fleet Air Arm Museum - Westland Wyvern TF1
www.fleetairarm.com Retrieved: 25 March 2010.

Specifications (Eagle 22)

References

Notes

Bibliography

* Gunston, Bill. ''World Encyclopedia of Aero Engines (5th Edition)''. Phoenix Mill, Gloucestershire, UK: Sutton Publishing Limited, 2006. * Lumsden, Alec. ''British Piston Engines and their Aircraft''. Marlborough, Wiltshire: Airlife Publishing, 2003. . * Rubbra, A.A. ''Rolls-Royce Piston Aero Engines - a designer remembers: Historical Series no 16'' :Rolls-Royce Heritage Trust, 1990.

External links

A working Rolls-Royce Eagle 22 model engineAdditional pictures of the same model enginePhoto of a Rolls-Royce Eagle 22
a 1947 ''Flight'' article {{RRaeroengines Eagle 22 Sleeve valve engines 1940s aircraft piston engines