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).
Engine components such as valves and bearings, materials used, overhaul periods, and experimental work.
| Identifier | ExFiles\Box 173\1\ img187 | |
| Date | 20th January 1934 guessed | |
| -9- Valves. Sodium cooled valves, which are supplied by Wilcox-Rich, are used and do not give trouble, but so far these valves have run with 2-B.C lead. Lead Bronze. This is used with big end bearings, and is supplied by Allison's and Bohn's. Both types are reported to give good results (but this does not coincide with Curtis-Wright experience of Bohn bearings). There does not appear to be any fixed form of high speed test. P. & W. conditions consist of running engine up to normal power and speed, relieving load to obtain 30% over speed, which is run in thirty second periods, restored to normal conditions for two minutes and repeated twenty time. This test is P. & W's interpretation of the high speed test, and whilst the authorities do not stipulate conditions of test, they prefer for their own benefit to carry out test stated which is approved by the government resident inspector. Magnesium. Many large castings are produced in magnesium, which is supplied by the Aluminium Company of America, Cleveland, who also supply aluminium castings. Overhauls. All P. & W. engines are now running 350 hours between overhauls, general condition after this period being remarkably good, and few replacements are necessary. They recommend, however, dismantling after this period in order that all parts can be thoroughly cleaned. Although this period has been laid down, engines in commercial service are running satisfactorily 500 hours between overhauls. Commercial flying companies are endeavouring to force this period. The average life of engines recommended by P & W. is 1200 hours, but some engines have seen 2000 hours service. Experimental Work. P & W. state that they spent between $800,000 to $600,000, which equals £160,000 - £120,000 per annum on experimental development and research. Since they are not subsidized by the Government, the whole of this expenditure is borne by the Company. | ||