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).
Tests conducted to diagnose and resolve a vehicle wobble issue.
| Identifier | ExFiles\Box 170\3\ img054 | |
| Date | 20th June 1935 guessed | |
| -2- Two adjustable rubber buffers (Cadillac front bumpers) were arranged as shown. These rubbers have a variable rate, so that tightening the screws actually stiffens the mounting of the engine in a rotary direction. Nothing we did with these had any effect on the wobble, so it was evident that we were moving in the wrong direction. B. The following tests were then made :- 1. With drag-link (Cadillac type) backed off 1/2 turn only we produced a wobble. The holding screws (see sketch) on the intermediate supports were removed. Rocking of the engine increased momentarily and stopped the wobble. 2. The drag link was given 1-1/2 turns slack and wobble again produced. The intermediate supports were still working part time, but could not work in tension since the screws were removed. The left hand intermediate was then removed entirely. Wobble could not be produced. 3. The drag link was given 3-1/2 turns slack and wobble again produced. The engine rock had now increased considerably and appeared to absorb most of the energy. The wobble was feeble but could be speeded up and made more violent by holding the steering wheel. The right hand intermediate support was removed. We could not produce wobble except by blocking the engine. The wobble stopped as soon as the block was removed. (Needle bearing kingpins were being used and equivalent of 3° caster. Front wheels had been re-set by bending the king-pin support to give positive camber.) 1. The car was taken out with 1/2 turn slack in the drag link. There was no wobble. 2. With 3 turns slack a slight wobble could be produced but it would not build up. 3. The adjustable rubber buffers shown in the first sketch on the front were then installed and just nipped up. | ||