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).
Outlining simple torsion tests for the Spectre Frame to determine the minimum number of bolts required to equal the stiffness of a spot-welded frame.
| Identifier | ExFiles\Box 94\4\ scan0011 | |
| Date | 17th July 1934 | |
| W. Bell. 4074 32Y To Hs.{Lord Ernest Hives - Chair} from Da.{Bernard Day - Chassis Design} c. E.{Mr Elliott - Chief Engineer} RHC.{R. H. Coverley - Production Engineer} SpectreCodename for Phantom III Frame. We wish to make some simple torsion tests to determine the minimum number of bolts to be used in the first pair of frames to equal the spot welded frames which will finally be used. You have a test piece made by the frame makers which has the same thickness of metal and the same diameter and pitch of spot welding as is intended for the final frames. If the torsional stiffness of this were determined experimentally, it could be used as a standard of comparison. A new test piece requires making, exactly like this spot welded test piece, except that the spot welding is replaced by bolts of the same diameter and approximately the same pitch, as those now being put into the first pair of frames. This new test piece is then subjected to the same torque as the spot welded piece, and if it is inferior to it in torsional stiffness, a fresh test could be made with double the number of bolts say, and so on. The pitch of the spot welds is approximately 1.25" and the pitch of the bolts now being put into the frame side members is approximately 3.25". As we want the side members to be as equal as possible to their final torsional stiffness when spot welded, it is probable we shall have to increase the number of bolts, but the above test would determine it. Da.{Bernard Day - Chassis Design} Hs{Lord Ernest Hives - Chair}/GRY.{Shadwell Grylls}15/KW 17.7.34. | ||