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).
Report page detailing engine performance characteristics including torque, fuel consumption, idling, smoothness, and starting.
| Identifier | ExFiles\Box 148\2\ scan0098 | |
| Date | 28th November 1938 | |
| -5- One of the great advantages of this engine is the high torque obtainable at low speeds. The torque curve in actual fact appears almost flat from 800 to over 2000 r.p.m. (b) Fuel Consumption. Specific fuel consumption was a minimum at about 1/2 load. .45 lb/BHP/hr. and a maximum at full load. .65 lb/BHP/hr. As mentioned above the fuels used were 72 and 87 octane. On occasions however, the latest 100 octane fuel was used. This had little effect on the performance of the engine apart from complete elimination of detonation. For normal purposes the 87 octane fuel was perfect satisfactory. Using the 72 octane fuel entailed a certain loss of power and an increased amount of pinking. (c) Idling. Idling was not good. Hunting occured whenever the r.p.m. dropped below about 750. However no work had been done to improve this weakness at the time and it is significant that in the case of the smaller engine (100 cu.in) a regular tick over of about 300 r.p.m. has been achieved. This was a result of modification to the exhaust manifold, port design, and phase angle on the crank pins. It entailed an extensive study of turbulence in the head and exhaust manifold. (d) Smoothness. The engine is smooth throughout the range, no vibration of any appreciable magnitude being felt either on power or overrun. (e) Starting. Starting from cold was good generally, probably due to the 'atomisation' of the fuel effected by the supercharger and the wide gap sparking plugs. | ||