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).
American piston design, evaporative cooling, special aviation fuel, and engine power ratings.
| Identifier | ExFiles\Box 179b\1\ img303 | |
| Date | 1st February 1933 guessed | |
| (2) Regarding the pistons used in America, mentioned by HS{Lord Ernest Hives - Chair}/LOV.{Mr Lovesey}, I do not quite understand the object of the cellular top, unless it is explained by the superior cooling by oil spray. I should not have expected the forging to have been at all difficult to make, but my imagination suggests that the best way to attack the problem would be an hydraulic forging like that used in forging a shell or a tube blank. Regarding the question of evaporatively cooled engines. I do not know any urgent reason at the moment for handicapping ourselves with evaporatively cooled engines. I rather understood that some of the difficulties of ordinary liquid cooling had been reduced by the universal use of non-freezing mixture. As we at present ask for a special aviation fuel, and the americans are using a still better one, can we not say that our high rated Mr. engine is intended for a high quality, but a practical, special fuel? My suggested rating of 750HP. was at revs. we chose. The military rating is probably M.S. on ground, and F.S. at 10,000 ft. If the air Ministry wish to go on with the old rating, well and good, but this high rating would be available for new 'planes, or foreign orders, and to compete with others if wanted. R.{Sir Henry Royce} | ||