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 rigidity, body construction, and stiffness tests for Spectre models.
| Identifier | ExFiles\Box 94\4\ scan0040 | |
| Date | 9th May 1935 | |
| - sheet 2 - provides re-enforcement where the frame receives the minimum amount of stiffening from the body – see diagram attached. The data supplied with Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}4/KW.3.5.35 has given us most valuable information but the complete SpectreCodename for Phantom III car tested for rigidity, namely 30-EX, is the one fitted with the first chassis built, in which the frame is assembled with small bolts instead of welding, and the body mounting is similar to our present Phantom 2's. The result, therefore, is not a true representation of what might be termed the production SpectreCodename for Phantom III. We should like torsion tests made on one of the latest SpectreCodename for Phantom III cars, preferably No.3. No.2. SpectreCodename for Phantom III has a welded frame and 19 instead of 10 points of attachment for the body. No.3. SpectreCodename for Phantom III has all of No.2. features, together with a re-enforced body and dashboard solidly attached to body. No.4. SpectreCodename for Phantom III, not yet built, should be a still further advance in the direction of greater rigidity in being panelled throughout in steel. We are pleased to note that Rm.{William Robotham - Chief Engineer} supports our proposal to produce a body based on the Cadillac method of coachwork construction. We believe this scheme provides very powerful cantilevers standing up from the frame at the front and the rear end, and that these two cantilevers joined by a roof built up with steel plating between the cant rails and the roof panel offers a very rigid construction. Owing to the relatively greater depth of the rear quarters this part of the body no doubt carries a considerable percentage of the strain, and this may account for the special re-enforcement used by Cadillacs in this locality. The effect of fitting a sunshine roof is certainly to reduce the stiffness of the front end of the body and it is argued that as we have to fit such a feature, and also a certain percentage of the convertible types of bodies we need a greater frame rigidity than otherwise. Personally I think that our tests show that we can never introduce into the frame anything like the amount of stiffness we want to put up the total rigidity of body and frame combined, due to the comparatively shallow depth dimensions to which the frame has to be limited, compared with the total depth of | ||