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).
Induction pipe experiments conducted on a 40/50 engine.
| Identifier | ExFiles\Box 75\2\ scan0223 | |
| Date | 26th May 1921 | |
| R.R. 235A (50 T) (S.H. 956, 19-2-21) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 3008 x2758 To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to BN.{W.O. Bentley / Mr Barrington} c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to EWT. for R.R.Inc. attention of OY. COPY x4305 x2758 Hs{Lord Ernest Hives - Chair}1/LG26.5.21. INDUCTION PIPE EXPERIMENTS ON 40/50 ENGINE. One of the first tests we made was to test a standard induction pipe fitted with glass windows at five points. From these we observed or proved the following results:- 1. That the amount of liquid petrol which can be observed varies with the quality of petrol. With poor petrol and the engine running full throttle at any speed up to 700 or 800 R.P.M., there is a slow moving stream of petrol to be observed in the pipe which crosses over the cylinders. Even with the best petrol we could observe this stream of petrol was still there but it is not so large. 2. If heat is applied to the induction pipe just above the carburetter the immediate effect of that is to increase the speed at which this stream of petrol is flowing and instead of having a deep slow flowing stream, there is a shallow fast flowing stream. If the heat is sufficient, most of the petrol can be vaporized. 3. We could not observe any indications of the petrol condensing along the induction pipe once it had been vaporized. 4. The condition which shows up the poor petrol and which it is most difficult to overcome, is what we now know as "loading up" of the induction pipe. This effect is that an engine can be run full power low speed and it will fire evenly and the torque will remain constant, and if the load is released and the engine allowed to increase in speed still with the throttle wide open, bad missing fire occurs due to richness for a short period, then once the excess of petrol has been got rid of, the engine will fire evenly. One gets this condition on the road when picking up from a very slow speed full throttle. The engine fires alright at low speeds but regularly at a certain speed, missing fire will occur due to richness. contd:- | ||