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).
Page from a report analyzing wheel shimmy and steering forces, including calculations and test results.
| Identifier | ExFiles\Box 29\1\ Scan111 | |
| Date | 8th October 1925 guessed | |
| contd :- -14- became heavy and objectionable. We placed friction in the stop pivots which opposed starting of shimmy. This did not stop it because the arm of the lever which makes the wheel oscillate was itself increased as well as the couple acting on the balance. Calculations applied to the 12-HP. Renault gave us the following results (see graph 5.) With a } F₁ x 0,12 = 500K x 0,085 d'ou F₁ = 355 kgs. normal } track. } F₂ x 0,12 = 500 x 0,105 - F₂ = 435 " With the } track } F₁ x 0,12 = 500 x 0,16 - F₁ = 670 " increased} by 150 mm.} F₂ x 0,12 = 500 x 0,18 - F₂ = 750 " and shows that the friction in the bushes A, and B, of the pivot axis is almost double when the track goes from 3.5° to 4°. It is evident that in spite of this braking effect one cannot think of increasing the distance between the plane of the wheel and the pivot axis since this would be detrimental to the solidity of the parts in question. Steering couple. To define the vague terms of 'light-ness' and 'heaviness' of the steering we carried out a series of tests (see appendix 1. tables 1. and 2.) which have permitted us to express in kgs-centimeters the couples necessary to steer when at rest and under these conditions we have tried the front wheels of various types of car. (The tests were carried out on a Delage on a surface of dry cement). If one looks at the table one gathers that since the War designers have tried to reduce as far as possible the steering couple without affecting the contd :- | ||