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).
Letter from a supplier regarding the specifications and delivery of special front springs.
| Identifier | ExFiles\Box 154\1\ scan0255 | |
| Date | 6th February 1935 | |
| MR.G.E.WOLSTENHOLME Copy for information. EXPT/L.Dept. HS {Lord Ernest Hives - Chair} /Lee.24/KW. Spring Dept.Tinsley. HWP/3/35. 6th.February. 1935. Messrs.Rolls-Royce Ltd., Nightingale Road, DERBY. Dear Sirs, 2.Special Front Springs. Your order No.76760. - dated 31.1.35. We are forwarding on Saturday next, 9th inst., the 2.- 1200 lbs Springs to the above order. You, of course, appreciate that the range of stress of these Springs is exceptionally high viz with 10" deflection to the loaded position it is 43.6 tons per square inch, and to the Maximum Bump position of 14" is 61.1. tons per square inch - figures which are 30% and 20% higher, respectively, than your highly stressed 20/25.h.p Standard low-rated Front Spring F.58602; also 50% and 31% higher, respectively, than your Standard 40/50.h.p. Front Spring F.83311, in which the deflection for the same loading is 4 1/2". Owing to the limitations imposed by your requirements, we decided to make the Mainplate .17" thick, - 2nd. plate .16" thick, 8. plates .15" thick, and the remaining 7. plates .14" thick, making a total thickness of 2.51". We have lubricated the Springs throughout and fitted 6 - Clips to each Spring as such were thought necessary in view of the very thin Mainplate employed. The finished weight of each Special Spring is 42.lbs, and your Standard 1200.lbs spring is 43.lbs. We trust these Springs will be found suitable for your purpose. Naturally, we do not look upon Springs of such a design as being normal for any type of suspension springs for road vehicles. Yours faithfully, THOS.FIRTH & JOHN BROWN LTD. Signed. H.W.Porter. for Director. | ||