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).
Proposal and testing of valve springs made from an aluminium alloy.
| Identifier | ExFiles\Box 88\4\ scan0182 | |
| Date | 4th November 1936 | |
| 2 8 4 To BY.{R.W. Bailey - Chief Engineer} Copy to Rm.{William Robotham - Chief Engineer} RHO Hl.(Lab.) Da.{Bernard Day - Chassis Design} E/Bn.{W.O. Bentley / Mr Barrington} E/PSN.2/MN.4.11.36. LPSmith Have you ever heard of this before. Rm{William Robotham - Chief Engineer} Valve Springs in Aluminium Alloy. We send you herewith LeC.5363 of a test spring to be made in aluminium alloy, which it is hoped will do the same work as the Bentley Valve Spring. From the comparison of the sizes of the two springs as shown on the scheme, it will be seen that the aluminium spring does not take up a great deal more space than the steel spring, and is of exactly half the weight. However, it should be appreciated that we have no experience as to the permissible maximum stress of the aluminium springs, and the comparison which is based on a maximum choc corrected stress of 18 tons/sq.inch. may look very different if a considerably lower stress has to be used. We wish to have three springs in all made and tested on the valve spring rig, one as drawn with a 45 lbs. load in position, and two others - one with a 35 lbs. load and the other with a 55 lbs. load, in order to give us some idea of the stresses which can be used. The springs are to be made of low silicon RR.59 alloy, and we understand from Hl. that this material can be obtained from High Duty Alloys, and the springs wound here. It is proposed that the tests shall be done initially at atmospheric temperature, but as soon as we have obtained some idea of the stresses at which we can operate, further tests will have to be conducted at more elevated temperatures. E/PSN. Att:LeC.5363. | ||