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).
Bench and road test report comparing a standard machine against an experimental machine.
| Identifier | ExFiles\Box 168a\3\ img436 | |
| Date | 30th September 1937 | |
| 3. Bench Test continued. Test. Standard Machine. Exptl. Machine. Cutting in 660 R.P.M. 380 R.P.M. Speed. 11.2 miles per 14.8 M.P.H. 1.25 hour. ratio. 12.4 M.P.H. 1.5 ratio. Sparking at 13 amperes, 13 volts Bad. Negligible. at 5,500 R.P.M. It will be seen that the experimental machine is later cutting in; but the difference is small when considered with a 1.5 drive ratio. On the other hand, there is a very large reduction in sparking, and consequently, increased reliability and length of life. Road Test. No bench endurance test was carried out, as the machine was fitted to car J2-M, which was about to leave for France. On this car it ran 17,000 miles, but, unfortunately a direct comparison with the standard machine cannot be made on this test as the car was fitted with an overdrive. This had the effect of reducing the engine speed, for given road speeds, by about 17%. Actually, however, when examined the machine was found to be in excellent condition. There was no appreciable wear of the commutator, while the wear of the brushes was only .001" per thousand miles run. The brushes were quiet and free in their holders, and the commutator free from blackening. The construction and trying-out of this machine, has, we think been worth while, as it indicates the correctness of the lines along which we have been thinking, but in view of the fact that over-drives are to be fitted to cars, it is doubtful whether the gain would be worth the extra expense. RM{William Robotham - Chief Engineer}/RC.{R. Childs} | ||