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).
Engine testing, automatic throttle control, detonation prevention, and the Stanton device, page 3.
| Identifier | ExFiles\Box 41\4\ Scan013 | |
| Date | 9th February 1929 guessed | |
| - 3 - Pilot opens throttle fully and engine runs this way for several seconds or minutes, until as internal temperatures rise, the working pressure at TDC begins to go up beyond the desirable limit. The pressure element then closes the throttle progressively to hold this maximum allowed IHP. As the plane climbs and engine gets warmer the throttle opening may be still further decreased. But when the IHP begins to fall off through decrease in atmospheric pressure the throttler is automatically opened in such a way as to keep the pressure at TDC constant. This engine was tested by P. & W. with a thermocouple at one of the rear spark plugs, about the hottest part of the engine. The engine was warmed up on aviation fuel and showed 450ºF (probably low) at this point when delivering full power. Commercial fuel of a known detonating brand was then turned on. Temperature and power showed a tendency to rise simultaneously. The control got to work immediately to reduce the boost and prevented detonation. The temperature rose to 515ºF and then after several minutes settled back to 480ºF with engine developing about 75% full power. This is the P. & W. 450 h/p radial air-cooled engine coupled to an electric dynamometer connected to give a V² characteristic simulating a propeller, compression 5-1/4. Mr. Stanton's contention appears to be that if the control in this crude form can prevent an engine hammering itself to pieces with such a radical change as a switch to commercial undoped fuel it should not be difficult to develop automatic control for every function of an aero engine so as to obtain the maximum desired output automatically under all working conditions. As compared with automatic control of boost by other devices such as barometer, etc., it appears that the Stanton device, while it takes account of the atmospheric pressure, also takes account of what use the engine makes of it and will therefore for example, shut down an overheated engine, and open up an engine which is running too cool. In conjunction with a variable-pitch airscrew like the Hele-Shaw it might be expected to give considerable fuel economies. The same device as shown in SK-382 can also be used instead of a "gate" on a naturally-aspirated "super-compressed" engine. Notes on ignition, carburation, and exhaust heat control follow. Yours very truly, M/Encl.3 | ||