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).
Modifications to spring stiffness, shock absorbers, and body mounting to improve steering performance.
| Identifier | ExFiles\Box 19\3\ Scan130 | |
| Date | 11th January 1930 guessed | |
| - 2 - Also use similar tire treads on all three sizes. 5. Spring stiffness:- Changing from 315 to 335 lbs/in. produced improvement in steering in 2401 series. Changing from 315 to 350 lbs/in. is probably the principal cause of improved steering at 2501 series (coupled with stiffer frame horns). 69-WJ should have springs with a clipped stiffness of about 370 lbs/in. according to drawing. We should check these and try effect of stiffening them about 10%. 6. Shock absorbers:- Changing these to 120% up and down with drilled HP valves might effect a slight improvement. 7. Hs.{Lord Ernest Hives - Chair} and Rm.{William Robotham - Chief Engineer} told us that considerable improvement could be made by tightening the rubber mounting of the four engine feet, so stiffening the front half of the frame. This is at the expense of increased torque reaction. 8. It might be permissible to try the effect of reduced pivot lean with the smaller wheels. Try 1-1/2°. Note: Although the body is of flexible type and non-standard mounting it is probably good to complete the tests with this body. We have found before that relying on torsional stiffness of coachwork to stiffen the frame is undesirable because some body types are much more flexible than others. Also there is the desirability of mounting coachwork at some future date on three points so that it is not distorted by the chassis and contributes nothing to stiffening it. On the other hand we should watch results when the new "Trouville" body is mounted as increased stiffness may tend to produce worse steering. OK M | ||