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 technical report on the 20 HP Sunbeam Car.
| Identifier | WestWitteringFiles\K\November1923\ Scan32 | |
| Date | 12th November 1923 | |
| 20 HP. SUNBEAM CAR. GENERAL PERFORMANCE. This model is very pleasant to drive. It does not profess to be particularly silent or smooth running but in spite of this, it does everything very nicely. Its acceleration up to 30 m.p.h. is not very good, and its top gear performance at low speeds on gradients is not so good as that of a 20 HP. RR. Its slow running is only fair, about 8 m.p.h. on top gear. Its road holding qualities and springing are very good. Its braking is excellent. ACCELERATION. Up to 30 m.p.h. distinctly inferior to 20 HP. RR. above that speed the acceleration is good. The maximum speed would seem to be over 60 m.p.h. The makers claim 65 m.p.h. ENGINE. There were no perceptible periods in this engine at any speed which we attained. The air intake of the carburetter was so noisy that it was impossible to estimate the silence or otherwise of the valve and timing gear. One was left with the impression that they were not over noisy. CARBURATION. Not really very good at slow speeds, the accelerator requiring a little humoring if maximum pick up is to be obtained. The worst feature is the noisy intake. BRAKES. These brakes are good, as one would expect on a demonstration car. They do not require undue exertion to operate them, do not appear to affect the steering much on cornering, do not jagger, and pull the car up very sweetly. Really an excellent example of what can be done with brake shoe - servo only. I was told that jaggering is overcome by relieving the forward edge of the shoe for an inch or two. The brakes are very much less effective when reversing, but suffice to pull the car up reasonably well. STEERING. Quite good, strong self-centering - no wobbles. GEARBOX. Gives a very easy change up or down and is singularly contd:- | ||