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 report on the effect of overdrive on petrol consumption for the Phantom III.
| Identifier | ExFiles\Box 91\2\ scan0199 | |
| Date | 31th July 1937 | |
| 300a CHATEAUROUX. Rm{William Robotham - Chief Engineer}/IMW{Ivan M. Waller - Head of Chateauroux}/4/JAB.31.7.37. To. Rm.{William Robotham - Chief Engineer} c. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} 32-EX. PHANTOM III. Tests on effect of Overdrive on Petrol Consumption An out and back run of 195 miles each way was made over a straight forward fast route. On the outward run direct drive only was used, and on the return overdrive only. The car was driven as gently as possible without prejudicing the performance, that is to say, full throttle and heavy braking were avoided. Maximum speed did not exceed 80 MPH. and about 75 MPH. was maintained on all the straight stretches. Driving conditions were as near as possible the same on each run, and the average speed was 55 MPH. in each case. The petrol consumption in direct drive was 7.4 m.p.g. and on overdrive 8.4 m.p.g. The average gearbox temperature was 95°c on direct drive, and 112°c on overdrive, and the maximum temperature 102°c and 118°c respectively. The highest gearbox temperature reached at any time during the mileage is 120°c. ---------- Rm{William Robotham - Chief Engineer}/IMW.{Ivan M. Waller - Head of Chateauroux} | ||