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).
Performance of special steel valves in a De Havilland Gypsy moth aeroplane engine and potential patent issues.
| Identifier | ExFiles\Box 154a\1\ scan0176 | |
| Date | 6th November 1929 | |
| To Rg.{Mr Rowledge} from ROY.{Sir Henry Royce} c. to WOP. (crossed out) c. to PY (crossed out) c. to Hs.{Lord Ernest Hives - Chair} X 4469. ROY{Sir Henry Royce}2/MC6.11.29 Mr. Tredgold, of The Hughes Johnson Company, tells me the Valves in the sealed Gypsy moth De Haviland Aeroplane which recently completed 500 hours without being touched were made in special Steel produced by Messrs. Cammell, and nitradized by the Hughes Johnson Company. The Air Board are especially interested in such Valves, and were discussing same with Hughes Johnson a day or so back - the result of which I have not heard yet. Messrs. Cammell and the Hughes Johnson Company claim that Valves so made in no wise infringe the Firth Patent. ROY.{Sir Henry Royce} | ||