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).
Frame stiffness experiments, comparing American cars and detailing the development and testing of the new Wraith frame.
| Identifier | ExFiles\Box 6\6\ 06-page210 | |
| Date | 4th June 1937 | |
| -3- sideways shake in the rear seats, and a feeling that the car is not in one piece. It also accentuates road shocks in the steering, and affects the controllability of the car. Some of the American cars with stiff frames are frightfully noisy. The Packard has an exceedingly stiff frame, but is not very noisy. We attribute this to the rubber in the front suspension. We are, therefore, working to see whether we can increase the rigidity of the frame without increasing the noise. This we regard as a pure experiment. ---------------- Briefly summarising the position, therefore, we consider that the heavy gauge Wraith frame with the drilled side members and the box drome is a very fair compromise. We may do a great deal of work before we get anything that gives a better average result. It should be appreciated that changing bodies over and making frame modifications takes a long time, and also a considerable period must elapse before reliable figures of merit can be obtained from any such alterations. We are having to check frame stiffness against noise value. We are, therefore, building the rest of the experimental cars with this frame, and, at the same time, carrying on with our experiments. We expect to have the third Wraith car by the end of June, and the first Wraith engine unit to the final specification by the 8th of this month. We think it would be wrong to send the Wraith engine unit to France before having ascertained on the Test Bed that it is going to be reasonably satisfactory. Any engine troubles are far more easily rectified on the Test Bed than on the road. On the other hand, we believe there are a lot of chassis parts which could, with advantage, go to France as soon as the third car is ready. As an example, the whole of the brake gear is novel, the front suspension has not been tested in France, nor has the gearbox and steering. We have had little or no experience with the new drilled frame. | ||