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).
Front spring tests for the 12-MC model, detailing modifications and performance outcomes.
| Identifier | ExFiles\Box 43\2\ Scan130 | |
| Date | 22th April 1926 | |
| Oy2-E-42226 X3800 April 22nd, 1926 To: Mr. Beaver Mr. Nadin Mr. Bagnall Mr. Hulley Mr. Caswell Mr. Southern Mr. Burton Mr. Knapton From: Mr. Olley EXPERIMENTAL REPORT Front Springs on 12-MC Supplementing my report of April 20th we have now completed Test III of the above report by taking the 43-1/2" front springs which had been made in such a way as to simulate our standard Silver Ghost stiffness, and mounting these exactly as on the Silver Ghost, i.e. shackled at the rear and with serrated shackles of present type and other shackle parts as on our present production. The pivot-lean was made approximately standard, that is one degree. H.C.B., W.H.H., Knapton and myself are in complete agreement that with this final change, which amounts to a complete simulation of present standard springing, the riding, and steering appear to be approximately the equal of a standard job. The high speed joggle has practically disappeared. So far we have found no trace of wobbling either low or high speed. We had expected possible trouble with the front brakes on a rough road due to interference of the brake cable radius and the radius of the front half of the spring. In practice we find no sign of irregularity in the brake operation. However it should be explained that to minimize the suddenness of the servo effect we are using servo levers on which the mean radius of the cam surfaces is increased from 1.087" to 1.800", thus decreasing the servo effect by 40%. Quite independent of the soft front springs we believe the reduced servo effect is an advantage in handling the car. | ||