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).
Issues and required modifications for a Dunlop Jack and Balloon Tyres on the 20 HP car.
| Identifier | ExFiles\Box 26\6\ Scan011 | |
| Date | 23th October 1924 | |
| To EY. from Hs.{Lord Ernest Hives - Chair} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to Wor.{Arthur Wormald - General Works Manager} Hs{Lord Ernest Hives - Chair}/TMW/LG23.10.24. 20 HP. DUNLOP JACK AND BALLOON TYRES. Handwritten notes: X4080 (top center), X4568 (crossed out, near title), X4080 (near title) The aluminium base supplied to us with the above Jack is not required for 20 HP. cars. The minimum height is 7", the first stage gives it a height of 12" and the 2nd. stage gives a maximum height of 15", total movement being 8". The greatest range of lift the Jack could be called upon to perform, is from bare rim to tyre inflated and clear of ground - this is 6½", thus giving a margin of 1½". The minimum height of 7" however is too much, as to miss the lowest point (i.e. the rear spring clip) when tyre is deflated, the Jack requires shortening by .500", and a further 1" with rim. It will be seen therefore that the Jack should be 1.5" shorter and have a minimum lift of 6.5". The handle supplied should be at least 6" longer. The dia. of the gearcase is such that it fouls the Brake Dust Cover before Jack is in the centre of spring clip by ¼". The angle of handle socket is too steep to clear the road springs or mudwings when winding. We experienced trouble due to a plunger not becoming disengaged, so that only the second stage of 3" was available - and dismantling was necessary to put it right. Hs{Lord Ernest Hives - Chair}/TMW. | ||