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).
Feedback and proposed improvements for the 20HP 'China' specimen, ahead of a 10,000-mile trial in France.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan146 | |
| Date | 5th June 1929 | |
| HS.{Lord Ernest Hives - Chair} } FROM R.{Sir Henry Royce} & E.{Mr Elliott - Chief Engineer} C. to SC. LHS.{Lord Herbert Scott} WOR{Arthur Wormald - General Works Manager} ORIGINAL SECRET R1/M5.6.29. X5840d. X5YYO. 20HP. 'CHINA' - 3 1/4 BORE LEAVING FOR 10,000 MILES TRIAL IN FRANCE. (1) The specimen brought to WW. yesterday appeared to be a very good car from the short time of driving and riding in it. (2) The engine is especially powerful at low speeds. (3) The speedometer reading is probably 10% high. (4) The Park Ward fabric body struck me as particularly good for silence and lightness, and really, with the other improvements, makes the 20HP. a distinct success. (5) During the visit of Messrs Robotham, Lovesey, & Hancock, the following points were discussed: (6) The steering wheel had a thicker rim than SS.{S. Smith}, and the controls were too high: I understand this is not up-to-date. (7) The brakes were smooth and not too sudden - i.e. rather safer than usual. (8) It was agreed that for fast light cars the back axle ratio might be tried 12/50 instead of 11/50 - (10/47 we consider too low at present.) It appeared difficult to get this specimen up to 70 MPH., because the high speed torque falls off rather quickly after 2000 revs. (9) To improve (8) we might produce a camshaft giving timing like SS.{S. Smith} This could easily be done by - Using present exhaust as inlet, rapid accelerations, 56 divisions. Angle between 116°: this will be easier for valve springs. Will Mr. Bailey kindly produce this. (10) Somewhere there is a carburetter (original) with larger throttle to which a larger air valve was fitted. This should be tried: the present is too small for the 60 to 70HP. this engine should give. (11) Also I should like to have the cutout fitted like SS.{S. Smith} for continental work. (12) This 'China' cyl. head is now considerably out-of-date, and it may be difficult to get great power at high speed as the valve passages are somewhat small. This has been improved on 'Japan', as can be seen from a comparative test, but every effort should be made to get the best from 'China', and the carburetter, camshaft, and cutout should definitely help. (13) The side wheel carriers were thought to be hardly stiff enough in themselves or their fixing, but the new bolts are a distinct improvement. We ought to have a British patent for this bolt scheme. R.{Sir Henry Royce} | ||