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).
Recommendation to increase vacuum pump piping diameter to 5/16 inch to improve fuel supply efficiency.
| Identifier | ExFiles\Box 64\1\ scan0035 | |
| Date | 20th March 1929 | |
| BY.{R.W. Bailey - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/ACL. c. to E.{Mr Elliott - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} [Handwritten] X7510 Hs{Lord Ernest Hives - Chair}/ACL1/LG20.3.29. 'SS{S. Smith}' VACUUM PUMP. [Handwritten, crossed out] X7510 [Handwritten, crossed out] X7230 We find as the result of experiment that the efficiency of the vacuum pump in supplying fuel is increased by approx. 25% by increasing the suction and exhaust pipes to 5/16 dia. The original size of these pipes was 3/16 dia. The greater part of the 25% increase is due to the larger suction pipe. The effect of the large pipe appears to be in forming a reservoir which allows the pump to build up a suction in the so formed reservoir during the time the float-operated suction valve in the autovac is closed, when it is discharging fuel into the autovac tank. We further proved this capacity effect by adding a tank of 8 cu.ins. capacity to the suction pipe when the fuel supply was again increased by approx. 12%. We therefore recommend that the vacuum pump piping should be increased to 5/16" dia. Hs{Lord Ernest Hives - Chair}/A.C.Lovesey. | ||