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).
Vehicle hill climbing performance versus acceleration capabilities, with specific reference to the Phantom model.
| Identifier | ExFiles\Box 178\1\ img009 | |
| Date | 12th October 1925 | |
| - 7 - REF. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG121025. output is required from them as in hill climbing, than when full power and increasing engine speed is required from them as in acceleration. For practical purposes, however, hill climbing performance is a very good guide to acceleration capabilities. In every case when a car is said to be able to climb a hill of a certain gradient, the car must be able to hold a given speed indefinitely on the hill; rushing a hill gives no information. Almost any car could rush Brooklands test hill on top gear, but none make a standing start on the 1 in 5 under the same conditions. We give a table of surmountable gradients and the acceleration that they represent. Actually on a car with a normal top gear ratio, the accelerations would be about 6% lower than those shewn in the graph due to the power absorbed increasing the kinetic energy of the wheels and flywheel. On lower gears, as we have previously pointed out, this discrepancy increases due to increase in flywheel speed. It will be at once apparent that as a normal Phantom loaded touring car can only climb a gradient of about 1 in 9 on top gear, its maximum acceleration in this condition can only be about 3 1/2 ft/sec^2 and anything claimed greater than this is of necessity hypothetical. (contd). | ||