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).
Specification for a jack for a 40/50 HP model fitted with 7-inch Dunlop low-pressure tyres.
| Identifier | ExFiles\Box 37\3\ scan 065 | |
| Date | 25th September 1924 | |
| To BY.{R.W. Bailey - Chief Engineer} from Hs.{Lord Ernest Hives - Chair} X.3175 Hs{Lord Ernest Hives - Chair}5/LG25.9.24. SPECIFICATION OF JACK FOR 40/50 HP. WITH 7" DUNLOP LOW PRESSURE TYRES. Minimum height of Jack 6.375". This dimension is necessary in order to get the Jack under the front axle with the wheel with a bare rim. Maximum height 16.75" under the rear axle to fit a new fully deflated tyre. Range of lift necessary 6". This is nearly an impossible range to obtain on any Jack. If however we agree to jacking up under the front springs instead of under the axle, the minimum dimension becomes then 9.375". The new Dunlop Jack appears to fulfil our requirements. At present the dimensions of this Jack are as follows :- Minimum height 7". Maximum height 15". Range of lift 8". If therefore we fix to this Jack a piece of packing 1.75" thick, it will then fulfil the range we require. [handwritten annotation: conditions] With the standard 33 X 5" tyres, the following are the Jack dimensions :- . Minimum height under front axle 7.75" from bare rim. Maximum height under rear axle 15.5". Range of lift 5". We will let you have a further report on the Dunlop Jack when we have had more experience with it. Hs.{Lord Ernest Hives - Chair} | ||