From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
The performance figures, specifications, and design details of a Junkers aero engine.
| Identifier | WestWitteringFiles\W\September1931-November1931\ Scan089 | |
| Date | 18th November 1931 guessed | |
| Since writing the above report, I have had a conversation with Mr. Tweedie, who informed me that the Junkers "engines" exhibited at the Commercial Show are only crankcases and cylinder blocks etc., having no internal parts whatever. He also said that some of the details of the design are not yet completed. The latest performance figures of the Junkers aero engine are very promising. It will be remembered that this engine has six cylinders of 4.75" bore and each piston has a stroke of 8.25". At 1700 RPM. a normal power of 700 BHP. is developed; this being equivalent to 93.0 lbs/sq.in. BMEP. On overload the engine will develope 97.0 lbs/sq.in. BMEP. at this speed, but the exhaust is very black. No consumption figures are available but it is understood to be between .375 and .400 lbs/BHP/Hr. at max. economy (part load). A scavange pressure of 5 lbs/sq.in. or slightly more is used. Rotational swirl within the combustion chamber is used as an aid to combustion, but owing to difficulties in obtaining a high swirl speed four injectors per cyl. are required. It is understood that much trouble has been encountered on this engine in the past from the gumming up of piston rings on the exhaust piston, but a careful study of clearances has overcome the difficulty. Hs{Lord Ernest Hives - Chair}/C W Parkinson | ||