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 lead bronze bearings and future manufacturing plans for a liquid-cooled engine.
| Identifier | ExFiles\Box 173\1\ img401 | |
| Date | 2nd February 1934 guessed | |
| To HS{Lord Ernest Hives - Chair} from RHC{R. H. Coverley - Production Engineer} -2- when fitted in aluminum housing; thin shell bearing only satisfactory in housings such as connecting rods. It is considered that the enormous improvement brought about by the introduction of lead bronze has made it possible for the American Air Force to increase their diving speed during bombing and, according to Mr. Gilman, machines are now diving at 500 MPH and he stated that in the development of the engine they contemplate running at speed of 4,250 RPM which, in case of Kestrel, would increase rubbing velocity of bearing 54 feet per second; consequently in repeat test, called for Allison bearing, it is intended to increase RPM under existing test condition, to ascertain maximum figure for bearing reliability. In the production of bearings, on small quantity basis of Allison process, there is a 40 percent increase in initial cost as compared with white metal, which no doubt will offset to some extent by improved quality, and fewer bearings should be rejected after endurance test. I am informed that good quantities of Lead Bronze bearings are being supplied to Napiers and that Lead Bronze bearings which successfully passed Type Test on Rapier Engine were supplied by Allison. In anticipation that action regarding license for manufacturing will be authorized, I have arranged to spend a week in the Factory and actually work on bearing production so as to become familiar with all points and general technique of manufacture. The standard of bearings is so high that I feel sure license will prove an investment as we will obtain benefit of Allison's ten years' development and, since Allisons are now absorbed by General Motors, with the increased facilities of their laboratories, constant improvement in bearing materials will be brought about, which we will reap the benefit of. Mr. Gilman promised to keep us up to date in any improvements in manufacture. In regard to the liquid cooled engine, which is being developed as previously reported, Allisons have prepared plans for the building of a factory for the production of this engine and also increased facilities for production of Lead Bronze in anticipation of motor car requirements. I saw the latest type connecting rod which is supposed to fit to the engine in question. The Marine Type connecting rod has been abandoned for several reasons: (a) Owing to the difficulty in manufacture; (b) The initial cost of bearing and cost of replacement. (c) Reliability. [Handwritten in left margin:] designed for the + | ||