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).
Methods to improve vehicle acceleration, including engine power and gearbox design.
| Identifier | WestWitteringFiles\T\2July1928-December1928\ Scan193 | |
| Date | 7th November 1928 | |
| [Text struck through: HS.{Lord Ernest Hives - Chair} DA.{Bernard Day - Chassis Design} F.{Mr Friese} BY.{R.W. Bailey - Chief Engineer}] } FROM R.{Sir Henry Royce} ORIGINAL SECRET R1/M7.11.28. [Text struck through: C. to BJ. WCR.] [Text struck through: " PN.{Mr Northey} LHS.{Lord Herbert Scott}] [Text struck through: " SG.{Arthur F. Sidgreaves - MD} OWB.] [Text struck through: " Mr. CLAREMONT] ACCELERATIONS. [Handwritten: X1725 X7310 X4550] [Handwritten: X7771 X8310] We think for traffic work a supercharger is not good, but for high speed passing - i.e. touring, continental racing, and even in the open country in England, it is certainly advantageous, but as this branch of the art is not what we cater for I have the impression that my previous opinion of not having a supercharger for a luxury car, or a really silent motor-car, is right. There remain two other ways of getting the result: (1) AMPLE ENGINE POWER. This we have in our Phantom, and will be improved in 'SS{S. Smith}', but we must be able to get really good output for engine size, and we can only do so by using the highest compression ratio allowable by limits of detonations, and this leads us into 8 cylinder construction unless we can isolate the unavoidable vibration of the 6 cyl. engine from the enclosed motor-car. (We have been partly successful in doing this with engine damper, and more recently with rubber engine and body mounting.) We are nearly or quite at the limit of low top gears, and the possibilities of our present practice. Therefore if nothing was in the way I would increase the power and capacity of our 20HP. engine for the forthcoming Show, but I fear this must be left for the following year. (2) The second way of getting increased acceleration is a more silent, and/or a more easily accessible 3rd. gear for acceleration from about 30 MPH. If the gear is very silent it need not be extremely accessible as one can use it for long periods instead of the top gear, and if it is easily accessible it need not be the last word in silence as one can change frequently; naturally both are preferred. The nearest way to get an easy change down to 3rd. is by freewheel in the sideshaft, which I schemed about 20 years ago, and though we experienced no ill effect we did not adopt it (for reasons already explained.) Such a freewheel can now be cancelled (by positive jaw clutch) when desired, and this combination may be patentable in such a position. To make the 3rd. gear more silent than our already fairly satisfactory 3rd., I think we might try a helical second pair (as well as our standard first.) We could try sliding these, or continual mesh, with jaw clutch and freewheel sideshaft, and also of a still higher 3rd. ratio to be more ( 1 ) | ||