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).
Petrol suction pump tests for the 'SS' engine and the resulting fuel delivery figures when using a standard autovac.
| Identifier | ExFiles\Box 40\4\ Scan283 | |
| Date | 3rd September 1928 | |
| To R.{Sir Henry Royce} from Ms/ACL. c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} 43579 Ms/ACL1/LG3.9.28. 'SS{S. Smith}' ENGINE. V7510 43579 We have carried out some tests with the petrol suction pump on the 'SS{S. Smith}' engine and obtained figures for the fuel delivery when coupled up to our standard autovac. The autovac was placed 32 ins. above the level of the petrol it had to lift as this is the usual equivalent lift on the chassis and the figure we always use for comparative tests. The suction pipe from the pump was connected with the autovac suction elbow which contained the usual non-return valve. On print V.407 is shewn the petrol delivery plotted against the engine r.p.m. and for comparison is shewn the normal fuel supply required by the engine when operating at full throttle. The fuel consumption curve of the engine is somewhat on the rich side - a Claudel carb. with cold induction system being used - and can be taken as the maximum we are likely to encounter. We see the autovac delivery falls considerably below the max. demand at speeds above 750 r.p.m. An interesting point to note is that if the non-return valve in the suction line between the pump and autovac is deleted the fuel delivery becomes considerably less at the low speeds as indicated by the lower dotted line on the blueprint. We have evidence to shew that this is caused by a characteristic of the suction pump due to the arrangement of the ports. The pump - see Lec.2470 and 2478 - has a stroke of contd:- | ||