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 Mr. Waller discussing petrol pump noise and the performance characteristics of a deturbulated cylinder head with a new ignition curve.
| Identifier | ExFiles\Box 101\2\ scan0027 | |
| Date | 9th July 1936 | |
| X5009 To Mr. I.M.Waller, Hotel de France, Chateauroux, Indre, France. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}22/KW.9.7.36. Thank you for your letter of July 7th. Petrol Pump Noise. If you isolate the petrol pipes from the dash, do you reduce the noise coming from the pump ? Deturbulated Cylinder Head with Ignition Advance Curve. In exchange for increased smoothness and better idling, we have decided that we have got to sacrifice a small amount of low speed performance. Practically speaking this loss is only up to 20 M.P.H. on top gear. It is not the slightest use timing the ignition 18° early in order to pick up this low speed performance, because if you do this it makes the ignition advance curve wrong over the whole of the rest of the range. As you will see from the attached curves, the loss in performance due to timing the engine at 14°, according to our test bed figures should be somewhere about 3 or 4%. We should like you to get actual timed, mean, both-way figures for acceleration with the two heads and ignition governors, and let us have the figures. We repeat, however, that to time the deturbulated cylinder head and the new ignition governor at anything under 14° is quite wrong. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||