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).
Steering gear design, comparing Marles and Saginaw systems, and the principles of oversteering.
| Identifier | ExFiles\Box 173\4\ img137 | |
| Date | 10th December 1935 guessed | |
| (2) feature at once. I have therefore given a good deal of time to trying to find anything about the Marles steering gear as made here which would seem to indicate a possibility of making our steering gear more effectively irreversible. I have sent you the discovery that considerable pains are taken to give the gear one light spot only, right in the centre, instead of, as I remember our gear, two light spots one on either side of the centre, with at anyrate, incipient slack in the middle, though the Saginaw wheel can be spun, the tightness is definite. It held a load of 100 lbs. on the end of the pendulum lever without reversing at the centre position. Saginaw cut their worms in the Fellowes Generating machine recently illustrated in "Machinery", having first rough hobbed them. But they do not consider they get as good a finish as they could wish, by so doing, and are experimenting with a Fellowes shaper which gives a very good finish. This is, however, experimental yet, and they advise us if we wish to make them, to get the generating machine. They experimented with grinding but gave it up on account of cost. There is one other thing, and that is that an oversteering car can stand a greater steering gear ratio than an understeering car. This is because the wheels have actually to be turned through a less angle than on an understeering car, to go round a given corner, since this greater ratio all helps to facilitate irreversibility, we might increase our ratio a little more, as according to Olley, our car very much oversteers. Da.{Bernard Day - Chassis Design} | ||