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 specifications and temporary features of a car under development, detailing components like gear ratio, controls, and brakes.
| Identifier | ExFiles\Box 69\2\ scan0094 | |
| Date | 4th July 1924 guessed | |
| -2- There is a new cylinder head being made with sparking plugs on each side of the cylinder which will reduce the detonation when the engine is carboned up. GEAR RATIO. The axle fitted to this car is a 16/52. It is necessary to have this axle if 80 m.p.h. is to be obtained before the valves leave their seats. We assume that for a speed model car it must at least be capable of doing 80 m.p.h. It is usual with a speed model to expect to accelerate on the gears if one wishes to obtain maximum acceleration. New Camshafts are in hand which might enable us to use a lower gear ratio and still obtain max. speed. CONTROLS. This engine is not fitted with a governor. The final EAC. is to have a governor. RADIATOR. The radiator on this car is only temproary. The final radiator will be larger. UNDERSHIELD. This is only temporary. We expect to reduce the heat under the scuttle on the front floorboards considerably when the throttle, undershield and bonnet are fitted. CLUTCH. This is the same as will be on the final car. SPRINGING. The springs on this car are standard strength for EAC.11 or EAC.111. The front springs, of course are considerably stiffer than the springs on the std. 40/50 HP. cars. STEERING & STEERING LOCK. The right-hand lock on this car is not as good as it will be on the final car owing to the wheel fouling the side steering tube. It is also probable on the final car the steering ratio will be lower. BRAKES. Standard adopted scheme. The pressure required on these brakes is on the high side compared with the average i.e. although the brakes are all made with the same leverages, their efficiencies vary a certain amount. On this car, slightly more pressure is required compared with the others we have fitted up. It is possible that the brakes will get more efficient and less pressure will be required as the car runs. We do not consider this is a fault. contd:- | ||