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 to a tester about recording engine revs, considering barometric pressure and tappet adjustments.
| Identifier | ExFiles\Box 37\3\ scan 111 | |
| Date | 13th September 1917 | |
| X.3178. EH1/LG13.9.17. Mr. Cliburn, Rolls-Royce Tester, C/O Martinsydes Ltd., Brooklands Track, Byfleet, SURREY. X.2910. X.1486. X.3178. Dear Sir, In taking a record of the engine revs: from day to day it would be very instructive if you could obtain barometric readings. The height of the barometer has a marked effect on the power. There would be a difference of 10 or 11 HP. in the power of your engine, if the barometer was 29" instead of 30". Although running against a propeller the lower the pressure the less resistance there would be to the propeller, so that the revs: should keep fairly constant. We want to get away from the idea of tuning up the engine after every run to obtain the revs. On test we never make any appreciable difference with any alteration to tappet adjustments. The Eagle engine in D.H.4 has run nearly 100 hours, the tappets we know vary 020" but as long as there (Contd). | ||