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).
And comparing different gearbox designs, focusing on 3rd speed, silence, and ease of gear change.
| Identifier | ExFiles\Box 15\5\ Scan074 | |
| Date | 5th March 1929 | |
| SG.{Arthur F. Sidgreaves - MD} from R.{Sir Henry Royce} c. to Mr. Fuller. c. to Mr. Beaver, c. to Mr. Olley. c. to Wor.{Arthur Wormald - General Works Manager} DA.{Bernard Day - Chassis Design} c. to Hs.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} 47310 R3/M5.3.29. SS.{S. Smith} AND 20 HP. GEARBOXES. X.7310 X.5310 X.2061 X.523 We have a very good indeed gearbox for 3rd. speed and general silence. It is the most practical and reliable simplest and lightest scheme we know. It lacks perfection in silence compared with the direct, and perhaps in principle. it is also less silent than one or two others using internal or all helical gears. It also lacks perfection in ease of change. I do not think that the slight additional silence that might be obtained by either the internal or all helical gears is worth what it would cost in lowering the above mentioned virtues. I would rather spend the money and energy in another direction. I have more carefully examined the internal geared 3rd. speed scheme on Gresham Paige (Ahlm Pearson), and as I have no drawings with me) there is no reason why this gear is easier or more silent to change. (I agree it is a more silent type of gear, and from my attempts at a design on these lines is fortunate in many respects.) I have no objection to a trial being made providing nothing better is suggested. The feature of changing without declutching is an operation rather easier to learn than ordinary double clutching, really surprisingly easy, and I concluded has nothing to do with the type of gear; the virtue in the specimen mentioned by OY. is more likely due to small multiple plate clutch.) Synchro The type 'Synchro-Mesh' I do not remember seeing, except some hazy notion of dog clutch which will only go in when synchronised, and then will fall in by spring pressure. If this is it then it is a very old scheme, but never tried by us. Personally I am most concerned in an easy change with passable silence. Nothing I have seen or tried has been really good for this purpose. Regarding OY's suggestion of our using the Stutz gate, at the moment I would prefer our more usual scheme, but I have not examined how it affects complication. We ourselves are trying 2 schemes, more or less our old ideas brought up-to-date both for ease of change even by the veriest novice, and one of them includes increased silence in 3rd. They are in the hands of Derby I believe, but may still be at WW., held up for other urgent work. It is probable that they will not be as good as the best produced by the whole world, but are worth a trial. contd :- | ||