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 suitability and faults of the Dunlop Jack and Balloon Tyres for 20 HP cars.
| Identifier | ExFiles\Box 53\2\ Scan140 | |
| Date | 23th October 1924 | |
| To BY.{R.W. Bailey - Chief Engineer} from Hs.{Lord Ernest Hives - Chair} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to Wor.{Arthur Wormald - General Works Manager} X4565 Hs{Lord Ernest Hives - Chair}/TMW1/LG23.10.24. 20 HP. X4565 DUNLOP JACK AND BALLOON TYRES. X.4080 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 6¾", thus giving a margin of 1¼". 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 ¾". The angle of handle sock 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. | ||