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 testing and stability of Spectre chassis jacks.
| Identifier | ExFiles\Box 139\2\ scan0441 | |
| Date | 19th December 1935 | |
| Bowering X1166 Rm{William Robotham - Chief Engineer} Er. and Her. c. Hs.{Lord Ernest Hives - Chair} Hy.{Tom Haldenby - Plant Engineer} RHE. E.4/HP.19.12.35. Jily SpectreCodename for Phantom III Jacks. We have had a SpectreCodename for Phantom III chassis jacked up on Sessions rams using a Smith hand pump attached in the usual position under the front floorboards. The two front rams are carried on brackets fixed to the front end of the frame, and have sufficient extension to pick the front wheels off the ground by means of the rebound rubbers. The two rear jacks are fixed in a normal manner to the rear axle with aluminium die cast brackets. The chassis when jacked up feels quite reasonably stable, and it is obvious that the jacks themselves are very stiff, the only perceptible movement arising from the anchorage. The front jack anchorage when made in the ultimate steel drop forging intended and brazed to the crossmember instead of the present temporary cast brackets merely bolted on will be still more rigid. The chassis as tested had not the power unit fitted but was weighted to the equivalent amount. We shall shortly have a complete chassis with the power unit fitted with a power driven pump and suitable control for connecting to the jacks, when the complete system can then be demonstrated. With regard to the Smith and Lockheed systems, we understand that front jacks are mounted on the linkage of the front suspension, and, therefore, move up and down with the suspension as unsprung weight. This scheme requires trying out, but we understand from the Sessions people that they have already had some experience with it in fitting their jacks to Buick independently sprung cars. The disadvantage they | ||