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 the development and testing of the 20/25 HP car model.
| Identifier | ExFiles\Box 91\1\ scan0194 | |
| Date | 5th January 1936 | |
| -2- 20/25 HP. We have had a 20/25 HP. car on the road fitted with a turbulent head since December 24th. The induction system fitted is the best we know of except that we have not the final drain scheme. The unit is fitted with an 11" Borg & Beck clutch. The general impressions so far obtained are - (1) The slow running is not so good as on Wor{Arthur Wormald - General Works Manager}'s car and Sg{Arthur F. Sidgreaves - MD}'s car. (2) The performance is not quite as good as on Wor{Arthur Wormald - General Works Manager}'s car. (3) The freedom from detonation is exceedingly good. (4) The clutch take-up is not considered satisfactory for production. (5) The engine unit is not as smooth as the big bore units we have previously run, but it is difficult to get a figure of merit for this on one car. The car has been running in Devonshire and a report will shortly be issued on its general behaviour. The unit in the car is not fitted with the final big bore 20/25 crankcase, as a radius was omitted on the drawing and consequently it was produced without this feature. New crankcase are being pushed through, however, and a complete engine should be available by the end of this week. We have done an endurance run on the bench with some semi-split sand-cast pistons, and these showed promise. We have not yet had any die-cast pistons. The completely new chassis which is represent-ative of the big bore 20/25 should be ready for the body [text struck through] by about the third week in Jan. The induction pipe with the final drain scheme to experimental sketches should be on test in 7 days' time. If it proves satisfactory, designs have been going along in parallel and these can be issued, detailed, and parts suitable for experimental test and production produced. | ||