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).
Analysis of transverse pivot lean and variable spring rating systems on model 19-G-IV.
| Identifier | ExFiles\Box 154\1\ scan0242 | |
| Date | 14th January 1935 | |
| -2- The transverse pivot lean on 19-G-IV is 8.30° which makes the steering impossibly heavy on corners. The excessive pivot lean was done in order to retain our present out-of-centre-point, which is small. We see no reason why the transverse pivot lean should not be reduced and the out-of-centre point in consequence increased. This however it is impossible to do satisfactorily with the existing parts. Variable Spring Rating. Dubonnet was very anxious that we should try his system with variable rating. We learnt later that our car was to be the first Dubonnet system with variable rating. We have been interested in variable rating systems, such as the Horstmann, which has given some impressive demonstrations on tanks, for the following reasons :- (a) It is claimed that less damping is necessary. (b) It is possible to rely on the increased leverages to check the wheel movement, thus saving the normal buffers. (c) Owing to the wheel rating becoming greater each side of the normal position, the tendency for the car to roll or develop into a state of large oscillations over a hump-backed bridge should be reduced. Two variable rating systems have been tried on 19-G-IV. Compared with the simple lever mechanism Expt. I increases the load on the wheel on bump and on re-bound, thus increasing the rating towards bump and reducing the rating towards rebound. On the road Expt. I proved to be unsatisfactory owing to the extremely low rating from normal to rebound. The car continually knocked the rebound stops and was very bad for rolling. Expt. II is the normal type of variable rating where the wheel is low rating in the normal centre position and then becomes higher rating when moved towards bump or rebound. | ||