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 and engineering analysis of a competitor's vehicle, likely a Jaguar, compared to a Bentley.
| Identifier | ExFiles\Box 126\5\ scan0029 | |
| Date | 2nd December 1937 | |
| -2- Rm{William Robotham - Chief Engineer}8/R.2.12.37. The engine has a flywheel, the weight of which is only half that of our own, which may account for part of the peculiar behaviour of the crankshaft. At all speeds the engine appeared to be apprec-iably smoother than the Bentley. Its low-speed pulling power, however, is very poor. Jaguars seem to have con-centrated on top power. They showed us some curves which indicated that they are quite as good as the 3½-litre Bentley at high speeds. In order to pick up 10 horse-power at the peak of the power curve they have gone to the trouble of fitting two entirely independent exhaust systems from the manifold to the back of the car. This is interesting in view of the fact that the work we have been doing recently has indicated that it is possible to save a good deal of power in this manner. They tell us that the benefit derived from the two exhaust systems can be noticed to an appreciable extent at speeds of 50 m.p.h. This was of more interest than their top speed figure. The general handling of the car was not very good. The ride was hard in spite of the fact that they have more deflection on their road springs than we have. We attribute this to inter-leaved spring friction and the wrong shock absorber characteristic. After our own servo system, the brake pedal felt spongy. It is difficult to believe that the brakes would prove adequate if the full engine output were used on a winding road. The gearbox had a very quiet second speed, but was relatively noisy on third. It was fitted with synchromesh second which did not function too badly. The weight of the car was said to be 31½ cwts. We think this is a very creditable figure for a car in which expensive materials are, presumably, not permissible. The general finish of the engine unit was very good. We noticed that their rocker cover was highly polished, and assumed that it was a die casting. We were told that it was a sand casting polished up. We should not have thought that this was conducive to economical production. We believe that the Jaguar could be of great use to us in checking up on the cost of our proprietary articles, | ||