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).
Test report and review of the 'SKYHI' hydraulic jack, detailing its shortcomings.
| Identifier | ExFiles\Box 37\3\ scan 070 | |
| Date | 27th May 1927 | |
| To BY.{R.W. Bailey - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/AJL. X3175 Hs{Lord Ernest Hives - Chair}/AJL1/LG27.5.27. 'SKYHI' HYDRAULIC JACK. This jack, which was submitted to us for test, does not quite meet the requirements of either of our chassis. We require a jack whose minimum unextended height is 6.25" to enable it to pass under the front and rear axles when a well base wheel without a tyre is fitted to the axle. The minimum height of the 'Skyhi' jack is 7.1". The maximum height is just sufficient - our requirement being 16.5". The adjustable initial lift of 1" could advantage- ously be increased to 2.75" at the expense of the hydraulic lift. The max. hydraulic (or mechanical) lift we require is 7.5". The hydraulic jack is very attractive in that it is so much easier to use than a mechanical jack; the effort to raise a car is negligible compared with a mechanically operated jack. The 'Skyhi' jack has a fault common to other makes of hydraulic jack viz: it is always rather difficult to remove the jack from under a car after use owing to the top of the jack not leaving the axle; it is not possible (on this or any other hydraulic jack) to lower the jack so that there is clearance between the car axle and the top of the jack, and so allow the jack to be easily withdrawn. The Skyhi jack sent to us for test purposes has, owing to its easy manipulation, been used very extensively, and this constant use has shown up its greatest failing viz: oil leaks from the glands. The oil leaks from the glands fitted where the first stage lift cyl. emerges from the jack body and where the second stage lift cyl. emerges from the first stage lift cylinder. The leaks are very extensive and prohibit any consideration of adopting the jack as standard equipment. We should be very pleased to test a sample in which this fault has been corrected, as apart from this and price considerations, it is a very attractive accessory. Hs{Lord Ernest Hives - Chair}/A.J.Lidsey. N.B. Any possible acceptance of this jack is of course subject also to alterations in dimensions stipulated to enable it to meet all our requirements. AJL. | ||