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).
Flexible engine mountings and body mountings, analyzing vibrations and frame 'jellyings'.
| Identifier | WestWitteringFiles\U\January1930-April1930\ Scan134 | |
| Date | 18th April 1930 | |
| -3- (b) Flexible Engine Mounting Three points. Larger amplitude, lower frequency vibrations with less well defined periodicity. Require quite large pot holes to set them off but once started are more likely to develop into high speed wobbles than (a). Steering inferior for selectivity and road shocks. (c) BODY MOUNTING. We are satisfied that the sub-frame has a considerable effect on frame jellying. We believe the distortion of the joints of the body provided a lot of damping on Phantom 1. The American Phantom 1 without a subframe at present at the works, is almost entirely free from jellying on the road. We can, however, make it jelly on the bump and when we do so the body distorts in the most alarming manner and could be quickly smashed up. Our own subframe bodies distort very little. The characteristic of the American car on the bumper is that the jellying is so damped that it dies out as soon as we get a few revs off the critical speed. We think the body is certainly responsible for this. We have additional evidence in that if we mount closed test bodies without subframes on Phantom ll chassis there is practically no evidence of jellying. Again, 14-EX having a Phantom 1 engine mounting with subframe jellies quite badly. We think that it is quite reasonable to credit the subframe with having an effect on the front end because altering the s-iffness of the frame centre by means of the cross produced such a revolution to the front end of the car both on the 20 HP. and the 40/50. Therefore, in improving the conditions for our bodies, we have taken a fair amount of damping from the | ||