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).
Progress report on road tests for the Spectre model after modifications.
| Identifier | ExFiles\Box 4\1\ 01-page250 | |
| Date | 7th February 1935 | |
| 4300 To E.{Mr Elliott - Chief Engineer} From Ha/Rm.{William Robotham - Chief Engineer} c. to WCR. c. to BY.{R.W. Bailey - Chief Engineer} Ha/Rm.{William Robotham - Chief Engineer}/S/KW.7.2.35. Progress of SpectreCodename for Phantom III. We have now run the SpectreCodename for Phantom III on the road with the following modifications :- (1) Single plate clutch. (2) Fabric coupling. (3) Engine with camshaft to LeG.4180. (4) Brake gear with adjustment locked up. (5) Crankcase with modification to prevent loss of oil pressure. The results of the test are as follows :- (1) This clutch is a great improvement with regard to pick-up, but will not free with the present pedal travel. As far as we can judge on one car the pick-up is just as good as any of our other single plate clutches. We are modifying the leverage to get the necessary separation. (2) The fabric coupling greatly reduces "chunking" in the drive. There is, however, still a certain amount of this at very low speeds when the engines misfires. We are making experiments to determine whether the flexibility of the coupling can be varied to improve this point. (3) The slow running is improved. The car can be made to idle evenly at 8 m.p.h. on top gear. The pick-up at slow speeds is improved. We are not, however, satisfied that we have got enough improvement in low speed pick-up, considering the amount of top speed power we have lost on this camshaft. We are investigating this. The idling with the car stationary is better, but too much sensation of the engine moving on its rubber mounting is still transmitted to the driver. This point can probably be improved by working on the engine mounting, but we consider that the compression ratio is still rather on the high side if the engine is to be completely unobtrusive. | ||