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).
Letter from Rolls-Royce Inc. Detroit to Rolls-Royce Ltd. Derby regarding crankshaft production, comparing steel types and forging practices.
| Identifier | ExFiles\Box 178\2\ img102 | |
| Date | 9th January 1940 | |
| COPY. ROLLS-ROYCE INC. 2-251 General Motors Building, Detroit, MICHIGAN, U.S.A. OY.1/DS/Jan.9.40. January, 9th. 1940. Rolls Royce Ltd., Derby, England. Rm.{William Robotham - Chief Engineer} Re: Crankshafts. I enclose copy of notes on visit to Wyman-Gordon January 5. This will serve to put you "au fait" with present position of this job. Lessells is shortly sending you a complete report on first heat of VCM steel, which looks very encouraging. W.G. are now starting a very rush job for Hispano-Suiza cranks, using "Hykro" steel and making two complete sets of forging dies, one representing French practice, and the other their recommended forging practice as used on Merlin cranks. The French practice is immensely heavy and involves rough machining all over before heat treat. The American practice is a bit closer than Vickers (about 237 lbs. on Merlin without test piece, as against 252 lbs. on Vickers forging) but is very much the same sort of thing except that W.G. use 3° draft angle instead of 7° The French are ordering dies and 800 forgings practical ly "sight-unseen". Total order 2400 forgings at present released. These figures are from memory. The use of Hykro instead of VCM is decried by Republic and W.G., principally because they are getting familiar with the latter and distrust the idiosyncracies of high chromium in the former. However, they are going to try it, with mental reservations that they may persuade the Hispano people to fall back on VCM if there is difficulty. Thought you would be interested in the trial of Hykro on this job, which relieves us of the need for ordering special expl. heats. Ov. | ||