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).
Value of aeroplane gearing, engine efficiency, and propeller safety at high speeds.
| Identifier | Morton\M8\ img038 | |
| Date | 10th December 1917 | |
| Cy. from R.{Sir Henry Royce} C. to Zeff. X. 1445 X. 2533 ORIGINAL R2/W10.12.17. 4 I have received a copy of your letter to Doctor Zahm and would like to point out that, so far as I know, on even the fastest of aeroplanes our gearing has more than proved the value of the extra cost and weight entailed. I do not agree with others who say the engine should be comparatively cheap and simple. The enormous value is not in the engine but in the efficient pilot first, and then the engine and the whole of the mechanism and that a small part of the engine if it adds to the efficiency on the whole cannot be considered in money value except if such money value is enormous and the parts were unprocurable. Finally, at this date, we do not consider a propeller for over 200 B.H.P. can be made to be safe and efficient if made to run at engine speed, if that speed is over 1500 revs. Even at our propeller speed with an adequate diameter of propeller the tip velocity is over 6 miles per minute. [STAMP: RECEIVED] R.{Sir Henry Royce} | ||