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).
Technical analysis document discussing various gearbox components like synchromesh, gears, shafts, and oil grooves.
| Identifier | ExFiles\Box 136\4\ scan0110 | |
| Date | 1st November 1933 guessed | |
| - sheet 4 - control of the sliding pieces on the 3rd motion shaft. The operation of these pieces could be observed on a box shown separately in the Annexe and it could be seen that they tilted considerably. I think that this feature might not have been detrimental if the actuating forks had been designed to control the collars and to thrust on them concentrically but instead of this their thrust was eccentric to the shaft axis, and so the combination appeared to work very badly. (2) [Handwritten in margin: PARTICULARLY] The top and third synchromesh is of the non-locking type and the second and first of the locking type. The latter construction suits the larger wheels of the lower gears and length is saved by its use, but whether this is the only reason I cannot be sure. I think that very probably the locking type of synchromesh would be advantageous on second and first as it at least enables easy engagement from rest to be obtained whereas the non-positive type resists always with whatever load is necessary to give reasonable immunity from crashing. (3) The pins to which you refer are not merely locating pins but are the cam pins which as Mr Birabin remarks in his report are of circular form acting in semi-circular cam slots. We have considered this before, as a means of saving expense, but have turned it down as the cam angle, which is very critical, is very susceptible to wear of the cam surface. (4) Bushes are shown between the 3rd, 2nd and 1st speed gears and the shaft. Spring loaded plungers are shown in the shaft and the only use for these that I can see is to prevent the bushes from rotating, although they seem to me to be quite inadequate for this duty. The bushes are located endwise by entrapped spring rings. [Handwritten: AS ARE THE LOOSE GEARS.] (5) The angle of the S.M. cones did not appear to be less than in our case. (6) The oil grooves in the S.M. cones were parallel to shaft axis. Our diagonal grooves may be no more expensive as we cut them with a continuous honing action which is very quick. (7) Reverse gears are as on the Alvis. (8) The gears are relatively narrower than we should use no doubt to reduce the length of the box to within what is practicable when no centre bearings are used. To compensate for the narrowness the shaft centre distance must be greater than it otherwise need be. SUMMARISING. Of all the points referred to we think that the only ones that are worth further consideration with a view to use by us are as follows:- | ||