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).
Summary comparing different change gear (gearbox) schemes, focusing on silence and ease of use.
| Identifier | WestWitteringFiles\U\2January1930-September1930\ Scan269 | |
| Date | 1st September 1930 | |
| -SG.{Arthur F. Sidgreaves - MD} ) FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} ) C. to C. WOR.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} C. to C. EP.{G. Eric Platford - Chief Quality Engineer} PN.{Mr Northey} ORIGINAL CHANGE GEAR SUMMARY, UPON WHICH OUR WORK IS BASED. It is understood and agreed that at least we must have a more silent 3rd. speed, but with idling and direct drive of the best possible silence. We cannot hope to get easy enough change with edge of teeth engagement, so that we must have at least jaw clutch engagement or brake control for the more important gears - (necessitating constant mesh gears.) We (R.{Sir Henry Royce} and WW.) cannot believe that we ought to interfere with the main clutch (even as Salerni or Wilson have done.) The foot control of this should be left as unaffected as possible. After years of experience we cannot see a way of getting a permanently good scheme except with epicyclic gear units. At present we have near completion 2 schemes which are alike in that the 1st, 4th, and reverse, are positive with jaw clutch engagement, and as these (except 4th.) are used when the car is standing there seems no disadvantage. The 2 schemes also are alike in the gear train, but, in the simpler (and perhaps less perfect to handle) form, the 2nd. and 3rd. are also obtained by jaw clutch. These are synchronised by brakes (which is possible owing to the epicyclic form of gears, otherwise a clutch is used.) The more elaborate scheme has for these 2nd. and 3rd. gears brake engagement, as used by Lanchester and Wilson, but in our case we only have 2 brakes instead of 4, and these need only be less than half the capacity - i.e. half, and one, engine torque, instead of half, one, two, and four, engine torques. It should be understood that most of the devices confined almost entirely to American cars (except the Wilson gear) cannot be considered to solve the problem because: SPOOL GEAR. (1) 3 pairs of gears always in mesh (both idling and (Graham-Paige) direct drive, and there is no reason for easier change, and Chrysler.) except - (2) 3rd. to 4th. very small ratio of change. (3) Some backlash in gears, clutch, or transmission. (4) Smaller HP. than our Phantom 2. Nos. (1) and (3) would not pass on our cars and would lead to endless production troubles and service. Reliability and wear may be passably good. (1) | ||