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 required dimensions for hydraulic jacks for the Phantom II vehicle, based on different wheel and tyre sizes.
| Identifier | ExFiles\Box 26\6\ Scan017 | |
| Date | 17th February 1930 | |
| Da{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} From Hs{Lord Ernest Hives - Chair}/AJL. C. to MX.{John H Maddocks - Chief Proving Officer} Hs{Lord Ernest Hives - Chair}/AJL.1/W.17.2.30. X3175. X4080 X3117. HYDRAULIC JACKS FOR PHANTOM 11. In reply to EV{Ivan Evernden - coachwork}2/11.2.30 it appears to us to be rather a peculiar procedure to (1) Disbelieve our figures. (2) Alter them to what you say is right; order jacks to your dimensions, and then- (3) Ask us if your figures are correct. In any case it appears that the figures you quote as our requirements "to the best of your knowledge" do not apply to Phantom 11; we should say they are old Phantom 1 dimensions. The following is our method of fixing the jack dimensions we require. We find from our experience in England and France that what we ask for is not excessive but the reasonable minimum to cope with every possible need. PHANTOM 11. (There are plenty of Phantom 11 cars on the road with 21" wheels x 6.75" tyres, they must be catered for in addition to 20" with 7" tyres.) Front Axle. Distance from under front axle to ground with bare wheel fitted (measured immediately under spring fixing) (a) 21" wheel = 6.0". *(b) 20" wheel = 5.5". Distance from under axle to ground with complete wheel and inflated tyre fitted and allowing .500" clearance between the tyre and the ground. (a) 21" wheel fitted with 7" tyre = 11.250". (b) 20" wheel fitted with 7" tyre = 10.750". | ||