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).
Response discussing the specifications and practicality of flexible road springs for a 20/25 HP vehicle.
| Identifier | ExFiles\Box 106\1\ scan0380 | |
| Date | 7th November 1935 | |
| x546 THOS FIRTH & JOHN BROWN LTD INCORPORATING THE WHOLE OF THE UNDERTAKING OF THOS FIRTH & SONS LTD AND THE STEEL BUSINESS PREVIOUSLY CARRIED ON BY JOHN BROWN & CO LTD ATLAS & NORFOLK WORKS SHEFFIELD.1 Codes: PRIVATE A.B.C. 6TH EDITION. BENTLEYS 1912 & 1929, LIEBERS, LOMBARD, MARCONI, WESTERN UNION 5 LETTER. Telephones: ATLAS & NORFOLK WORKS SHEFFIELD 20081 (11 LINES) TINSLEY WORKS SHEFFIELD 41193 SCUNTHORPE FOUNDRY SCUNTHORPE LINCS 22 Telegraphic Addresses: FIRTH SHEFFIELD ATLAS SHEFFIELD London Office: 8, THE SANCTUARY WESTMINSTER, S.W.1 Telegraphic Addresses: MESMERIC, PARL, LONDON ALDWARKE, PARL, LONDON Telephone Number: 8310 VICTORIA YOUR REFERENCE Ha/Les.30/KW. Exptl Dept. REGISTERED OFFICE: ATLAS WORKS, SHEFFIELD OUR REFERENCE WHICH PLEASE QUOTE HWP/37/35. Spring Dept, Tinsley. 7th.November.1935. Messrs.Rolls-Royce Ltd., Nightingale Road, DERBY. For the attention of Mr.Leslie. 20/25.h.p. Flexible Road Springs. Dear Sirs, Thank you for your letter of 5th inst. We have carefully studied your suggestions for these Springs - but fail to see how we can recommend for production purposes Springs possessing similar characteristics to those we sent to you on 11th ultimo - and at the same time reduce the range of stress to the maximum bump position so as not to exceed 45 Tons per square inch. FRONT SPRINGS. These are specified to have a deflection of 5.1/2" for a given load, with 1/2" positive camber loaded - and maximum bump position 1.95" beyond the loaded position - making a total of 7.95" through which the Mainplate would have to travel from the free to the maximum bump position. Calculation reveals that for such conditions, coupled with a specified range of stress not to exceed 45 Tons per square inch, the thickness of the Mainplate should be .157" or thereabouts - a thickness not recommended because impracticable. REAR SPRINGS. These are specified to have a deflection of 8" for a given load - at 1/2" negative camber loaded - and maximum bump position 4.3/4" beyond the loaded position - making a total of 12.3/4" continued overleaf......... | ||