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 standard spur gear and helical gear oil pumps.
| Identifier | ExFiles\Box 149\2\ scan0072 | |
| Date | 3rd August 1933 | |
| BENSPORT OIL PUMP COMPARISON BETWEEN STD. SPUR GEAR, AND HELICAL GEAR PUMPS MOBILOIL "D" 75°C 25 LBS/D" DELIVERY PRESSURE STANDARD E.53658 HELICAL EX 11454 ARRANGEMENT DRG NOS Graph: Y-Axis: DELIVERY PTS/HR X-Axis: PUMP SPEED R.P.M Data Lines: HELICAL GEARS EX. 11449/50 STANDARD GEARS. E.51764/5 Tables: HELICAL PUMP GEAR | END CLEARANCE | RADIAL CLEARANCE DRIVER | .002" | .001" DRIVEN | .0025" | .0015" STANDARD PUMP GEAR | END CLEARANCE | RADIAL CLEARANCE DRIVER | .0015" | .0025" DRIVEN | .0015" | .0025" | ||