| Eagle | |
|---|---|
 Rolls-Royce Eagle 22 at theFleet Air Arm Museum. | |
| Type | Liquid-cooled H-24 piston engine |
| Manufacturer | Rolls-Royce Limited |
| First run | March 1944 |
| Major applications | Westland Wyvern |
| Number built | 15 (Eagle 22) |
TheRolls-Royce Eagle Mk XXII[1] is a British 24-cylinder,sleeve valve,H-block aero engine of 46litre (2,807cubic inches)displacement. It was designed and built in the early-1940s byRolls-Royce Limited and first ran in 1944. It was liquid-cooled, of flat H configuration with twocrankshafts and was capable of 3,200horsepower (2,387kW) at 18psi boost.
The Rolls-Royce design team realised that producing a scaled-up version of theirGriffonV-12 engine would lead to excessively largecombustion chambers and problems withdetonation.[2] The team concluded that a larger number of small cylinders would be the answer and considered anX-24 design. This layout had previously caused unreliability with theRolls-Royce Vulture due to the need to fasten fourconnecting rods in a complicated arrangement to a commonbig end bearing.[2]
The designers finally settled on an 'H' layout with two crankshafts and 'blade and fork' connecting rod attachments, the crankshafts being connected through thepropeller speed reduction unit. The new engine followed the layout of theNapier Sabre and similarly usedsleeve valves but with a simplified drive system.[2]
A two-speed, two-stagesupercharger andintercooler were used to compress then cool the air-fuel mixture, following Griffon andMerlin practice. Starting was byCoffman starter. An auxiliary shaft driven by the lower crankshaft operated the main coolant pump, intercooler coolant pump, pressure and scavenge oil pumps and afuel injection pump.Piston ring failures andcylinder head sealing problems were experienced during early flight testing.[2]
The Eagle was never fitted to a production front-line fighter, as it was overshadowed by a new wave ofturbojet engines, such as theRolls-Royce Derwent andturboprops such as theDart andArmstrong Siddeley Python. Fifteen Eagle 22s were produced to power prototypes of theWestland Wyvern fighter/torpedo bomber because of delay in the development of the Python.[2]
Supermarine specified the Eagle in their 1944 proposal for a single-engined Naval fighter, theType 391, but the proposal was not followed up.[3]
46H Eagle I
46H Eagle II
46H Eagle (20 srs) 22
Data fromLumsden.[6]
Related development
Comparable engines
Related lists
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