Developing a formula for the ignition break position for starting the Goshawk engine.
| Identifier | ExFiles\Box 54\5\ Scan252 | |
| Date | 9th January 1924 | |
| 9.1.24. (Handwritten Notes: Revised 31.10.24 See X5680) X.3485 - GOSHAWK(Aero Engine)(Codename for 20HP Car / Aero Engine after Kestrel(Aero Engine)) BATTERY IGNITION. X.3949. Development of formula giving position of lever on quadrant, at which ignition break should take place on retarding lever, for starting engine. The position for which a formula is required depends upon four quantities, each of which is represented by general symbols in the first instance. The quantities are :- (1) The make ratio of the contact breaker which we will call r (usually .5 to .55). N.B. The make ratio is defined as the fraction Period of make --------------------------------------------- total period (period of make+period of break) (2) The fully retarded ignition setting of the engine. (usually about 10°). Let this be d degrees after dead point. (3) The available range of advance (hand advance only and reckoned on engine). This for the present ignition is 40°. Call this R degrees. (4) The position in which the engine has stopped. Assume this to be 8° before dead point for some particular cylinder. (This will be in the neighbourhood of 60°). Since fully retarded break is set to d degrees after dead point, the fully retarded make will be 120 r-d degrees before dead point. Contd. | ||
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).