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 discussing the inadequacy of the vacuum pump for windshield wipers and recommending the development of electric wipers.
| Identifier | ExFiles\Box 23\3\ Scan143 | |
| Date | 27th August 1929 | |
| X1087. ROLLS-ROYCE OF AMERICA, INC. SPRINGFIELD, MASS. OY-5 August 27, 1929. Mr. E.{Mr Elliott - Chief Engineer} W. Hives, Rolls-Royce, Ltd., Derby, England. Dear Mr. Hives: VACUUM PUMP SECTION 5140. Supplementing OY-2, August 26th, we find the displacement of a "Trico" windshield wiper to be approximately 14 cubic inches per double stroke, or at 60 double strokes per minute = 850 cubic inches per minute. Or for two wipers about one cubic foot per minute. At 30 m.{Mr Moon / Mr Moore} p. h.{Arthur M. Hanbury - Head Complaints} this would be two cubic feet per mile, against a total vacuum pump capacity of .800 cubic feet per mile. It is evident, therefore, that the vacuum pump capacity would have to be multiplied by three at least to take care of windshield wipers, and that we had better forget this idea, and get busy on developing a source of good electric wipers. I think you will agree that a vacuum pump of 3 times the existing capacity (or the present pump run at 3 times the speed) would be impossibly noisy. Yours very truly, ROLLS-ROYCE OF AMERICA. Maurice Olly | ||