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).
The limitation of delivery in Bentley Oil Pumps due to inlet pipe restrictions with increased capacity pumps.
| Identifier | ExFiles\Box 149\2\ scan0096 | |
| Date | 26th January 1935 | |
| To Rm.{William Robotham - Chief Engineer} c. to E.{Mr Elliott - Chief Engineer} +238 Hs{Lord Ernest Hives - Chair}/WB.{Mr Brazier/Mr Bell}1/KW.26.1.35. Bentley Oil Pumps. Limitation of delivery - due to Inlet Pipe restriction - with special reference to increased capacity Pumps. In view of the present tendency to increase the capacity of the Bentley oil Pump, the results shown in the accompanying graph are worth of attention. Taken with an inlet pipe equivalent in length and diameter, to the standard installation, using the largest and the smallest capacity pumps submitted to date for this type of engine, a maximum installation capacity of 2800 pts/hr. is indicated, at an oil temperature of 75°C. The small capacity (standard) pump delivery was proportional to the speed up to 2500 P.R.P.M. (5000 E.R.P.M.) but with the large capacity pump, proportionality ceased above 1750 P.R.P.M. (3500 E.R.P.M.) the maximum delivery being reached at 2750 P.R.P.M. (5500 E.R.P.M.) approximately. The increased capacity pumps to LeC.4288, recently tested, were of slightly lower capacity than the increased capacity type illustrated, and it is estimated that proportional delivery ceases at 2000 P.R.P.M. (4000 E.R.P.M.), the maximum being reached at 3250 P.R.P.M. (6500 E.R.P.M.) approximately, with that size of pump. Hs{Lord Ernest Hives - Chair}/W.Bell. NOTE: This trouble is hardly within our speed range at present. Rm.{William Robotham - Chief Engineer} | ||