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).
The rigidity of the Spectre frame, comparing its weight and stiffness to the Cadillac and Phantom II frames.
| Identifier | ExFiles\Box 94\4\ scan0039 | |
| Date | 9th May 1935 | |
| GRY{Shadwell Grylls} {327} To Sg.{Arthur F. Sidgreaves - MD} and Wor.{Arthur Wormald - General Works Manager} from E.{Mr Elliott - Chief Engineer} c.c. Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} JLE.{J. Lee Evans - Chassis Test Manager} LA.{L. A. Archer} De. EV.{Ivan Evernden - coachwork} Rigidity of SpectreCodename for Phantom III Frame and SpectreCodename for Phantom III Bodies. -------------------------------------- In designing the SpectreCodename for Phantom III frame we did not work to an American model. We set out to produce a design based on first principles which should possess the maximum rigidity for the minimum weight, and with the stiffest features disposed to obtain maximum effect with coachwork fitted. An analysis of report Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}4/KW.3.5.35 shows that we have succeeded reasonably well. From the information at present available the SpectreCodename for Phantom III frame should be no heavier than the Phantom 2 which is 316 lbs. The Cadillac chassis frame is said to weigh 560 lbs, that is, 244 lbs more. In spite of this difference the SpectreCodename for Phantom III frame without dashboard is 9% stiffer than the Cadillac frame and with dashboard 26% stiffer based on two degrees of angular twist. Incidentally the SpectreCodename for Phantom III frame is about ten times stiffer torsionally, which is what the aforegoing figures also refer to, than Phantom 2. In the case of the Cadillac frame cross, since the total car is 24 times stiffer than the frame, this cross goes out of action when the body is fitted and by virtue of its position far back under the rear floor, does practically nothing to help front end rigidity. Apparently front end rigidity has to be looked after by the deep side channels anchored to the body itself. Such a system is wasteful of weight. The SpectreCodename for Phantom III cross was, with a certain amount of fore-thought, placed as far forward as possible and its centre is only 5 1/4" from the front wheels, compared with a similar dimension of 9 1/4" for the Cadillac. The SpectreCodename for Phantom III cross does not go out of action entirely when the body is mounted but | ||