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).
Investigation into the characteristics of the accelerating pump on the Goshawk carburettor.
| Identifier | ExFiles\Box 179b\3\ img134 | |
| Date | 3rd February 1933 | |
| R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Pur. c. to HS.{Lord Ernest Hives - Chair} c. to SFr. c. to Rg.{Mr Rowledge} c. to c. to RV. ORIGINAL Hs{Lord Ernest Hives - Chair}/Pur.1/MA.3.2.33. x4658 GOSHAWK CARBURETTOR. ACCELERATING PUMP. In view of the characteristics of the accelerating pump on the Goshawk carburettor, when in flight, supplying fuel to the engine in considerable quantities, at every movement of the throttle, we have carried out a series of static tests to investigate the best means of ensuring its operation as a pump without interfering with the normal functioning of the carburetter, other than when required. When accelerating, the requirement of the engine are momentarily, a considerable increase of fuel delivered to the induction system, the amount being sufficient to supply the engine, until the carburetter is functioning correctly to comply with the change of throttle position. When this condition is attained, the accelerating pump is no longer required to function. The general acceleration of the engine is such that with the pump disconnected, the engine will accelerate from slow running to rated power in a time elapse of 3 seconds, but as it is possible for the throttles to be opened in considerably less time, it is necessary for the pump to supply an excess quantity of fuel to bridge the "dead" period, and to investigate the pump to operate on these lines, forms the object of our tests. The various systems and static results are tabulated and summarised in the following notes. (1) EXISTING STANDARD SYSTEM. (AS ON KESTREL 11s & 1031 ENGINES.) PLUNGER GAP .015". SPRAYING ORIFICE .125". Fuel is lifted to a height of 7 ft. and is supplied for a period of 3 1/2 seconds when operated over its full range. Has the disadvantage of supplying fuel at every movement of the throttle irrespective of rate of opening. | ||