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).
Automatic transmission systems, discussing overgear, creeping, and comparing competitor technologies.
| Identifier | ExFiles\Box 178\2\ img053 | |
| Date | 26th March 1940 | |
| Rm.{William Robotham - Chief Engineer} - page 4 Serial No. 53 OY 13/D/Mar.26.40 way up taken care of principally by switches worked from accelerator pedal. If car coasts down a hill in overgear, it stays in overgear and does not free wheel. If it pulls up to a light at the bottom of the hill, it stays in overgear until the car stops, when all clutches are automatically freed. If the light changes before car pulls up and accelerator is pressed, the governor control has already selected in advance the gear most suitable to engage for the speed at which the car is rolling. Apparently, the system at present during acceleration is to shift during successive releases of the accelerator following bursts of acceleration in each gear. Am not clear on this. Walter wants me to try the car at an early opportunity, and I will then report further. At any rate, a serious attempt is being made for simplified controls. Creeping Car uses a fluid flywheel without supplementary friction clutch. W.R.C. thinks that Olds have gained by using the split-drive method and only putting 40% of torque through the fluid drive, but that the gain is not worth the expense. Proposes to use plain fluid drive and make it big enough. He did not go into question of creeping, but will probably do like Chrysler and use a new return valve on the hydraulic brake system which is only released when accelerator is depressed. He confirms that no one without the resources of G.M. should tackle the Hydramatic. He believes the Cotal system can be made to operate just as well, though, after testing both, he says they do not compare at present. He thinks his costs can be not much more than half the Hydramatic. Am not sure that I may not be betraying his confidences in letting you know about this, but, from his invitation to ride the car, I gathered that he was chiefly concerned that G.M. should not get wind of it. As he says, G.M. take five years on a job like this and then cannot make it in adequate quantity. The smaller fellows have to get something out in six months and make it for less money. I suggest that you just quietly forget the conventional transmission of which you sent prints. This is not going to satisfy the customers after the war for long enough to pay for the tools. The American fluid drive details made from pressings are wonderful | ||