Letter from an engineering firm proposing a new transmission system, called a booster.
| Identifier | ExFiles\Box 156\4\ scan0026 | |
| Date | 12th October 1928 | |
| JOHN CRAIG & CO. GENERAL AND ELECTRICAL ENGINEERS. AUTOMATIC MACHINERY. TELEPHONE: GERRARD 0908. J. {Mr Johnson W.M.} F. {Mr Friese} N. CRAIG. 9, REGENT STREET, LONDON, S.W.1. IN REPLY QUOTE October 12th 1928. P. Northey, Esq. Messrs. Rolls-Royce, Ltd., Conduit Street, W.1. Dear Sir, I have been at work on the gear-box, or rather transmission, question, and a particular solution which you have seen will probably be in use on the popular priced cars. There is also a very complete solution which I have produced and am anxious to see in use, as I believe it is perfect. If you can pass the matter on to the Technical Department, I shall be very grateful and will do whatever they suggest after consideration. In a low-powered car the driver is using the gears at all times, whereas in a Rolls-Royce the engine will take the load as a rule on top-gear. The new-transmission I call a booster, since the function is to transmit torque directly in the ordinary way but to assist when starting or when accelerating. The point of the improvement is that the drive is taken up by accelerating, and clutch, gear-lever are dispensed with. There is a certain amount of objection to special gears, as these are often continuously working, and are not quite the same thing as direct drive. However my booster system does give a genuine direct drive, and as well as that, an extra torque when the load on the transmission makes it desirable. Below a certain speed the neutral position results. As the drive is always direct the complete transmission-box is small and efficient. Naturally when the booster is in operation the overall gear-ratio is increased, and the conditions correspond to a lower gear. Yours faithfully, John Craig | ||
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).