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 distortion and twist, analyzing movement between cross members with varying engine bearer tightness.
| Identifier | ExFiles\Box 75\3\ scan0421 | |
| Date | 7th April 1925 guessed | |
| -3- This confirms that the frame distorts as in 2. (a) and proves that the direction of twist between the 2nd. and 3rd. cross members is opposite to that between the engine feet and the 2nd. cross member. Experiments have been tried with the rear engine suspension slack and tight. Movement between engine Movement between feet and 2nd. cross member. 2nd. & 3rd. X members. Bearers slack. Horizontal .375 .312 Vertical .312 .144 Bearers tight. Horizontal .250 .250 Vertical .125 .160 + + It will be noticed that with the bearers tight the vertical movement between the 2nd. and 3rd. cross members is greater than when they are slack. This may be accounted for by the fact that when the frame is stiffened with the engine feet being tightened the twist will take place at a maximum further to the rear of the chassis than when freer movement is allowed at the forward end. Sketch showing relative (exaggerated) positions of the side channels in cross section at different positions of maximum bump. [Sketch of two cross-section channel shapes showing distortion] Between engine feet and 2nd. cross member. | ||