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).
Test results for a tank oil pump, detailing delivery rates and relief pressures.
| Identifier | ExFiles\Box 25\1\ Scan024 | |
| Date | 22th April 1932 | |
| γ 4688 From HS{Lord Ernest Hives - Chair}/Bl. HS{Lord Ernest Hives - Chair}/Bl.6/MA.22.4.32. TANK OIL PUMP. Lec's 3032 & 3034. The following deliveries were obtained using Motorine "C" oil at 80°C, with the relief valve blanked off, the main pump delivery against a pressure of 20lb/sq. in., and the scavenger pump delivery unrestricted. Pump Speed R.P.M. | Engine Speed R.P.M. | Delivery Pts/Hr. Main Pump. | Scavenger Pump. 500 | 1000 | 460 | 500 1000 | 2000 | 850 | 960 1500 | 3000 | 1440 | 1600 Although the relief valve details were the same as the standard 20/25HP, it was found necessary to extend the spring to 1.800" free length, and to fit two extra adjusting washers (making 7 washers in all) in order to obtain an initial relief pressure of 20lb/sq.in. This allowed a valve lift of approximately .100" before the spring became choc-a-bloc. A standard spring at the same setting gave an initial pressure of 16 lb/sq.in., With the full main pump delivery diverted through the relief valve the following relief pressures were obtained. Pump Speed R.P.M. | Relief Pressure. Spring as fitted. | Standard Spring E.50295. 1000 | 38 lb/sq.in. | --- 1250 | 40 " | 37 lb/sq.in. 1500 | 45 " | --- 1 print att: HS.{Lord Ernest Hives - Chair} P.M. | ||