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).
Performance comparison graph between a standard spur gear and a helical gear Bensport oil pump.
| Identifier | ExFiles\Box 149\2\ scan0080 | |
| Date | 3rd August 1933 | |
| BENSPORT OIL PUMP COMPARISON BETWEEN STD. SPUR GEAR & HELICAL GEAR PUMPS MOBILOIL "D" 75°C. 25 LB/D" DELIVERY PRESSURE. STANDARD PUMP E 53658 | ARRANGEMENT DRGS. HELICAL PUMP EX 11454 | Y-AXIS: DELIVERY PTS/HR X-AXIS: PUMP SPEED R.P.M. GRAPH DATA: HELICAL GEARS Ex 11449/50 STANDARD SPUR GEARS E 51764/5 TABLE: HELICAL GEARS GEAR | END CLEARANCE | RADIAL CLEARANCE DRIVER | .002" | .001" DRIVEN | .0025" | .002" TABLE: STANDARD PUMP GEAR | END CLEARANCE | RADIAL CLEARANCE DRIVER | .0015" | .0025" DRIVEN | .0015" | .0025" | ||