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 Thos. Firth & Sons, Ltd. discussing the performance and friction testing of experimental 40/50 HP springs.
| Identifier | ExFiles\Box 52\2\ Scan090 | |
| Date | 25th August 1923 | |
| Telegraphic Address: 'FIRTH SHEFFIELD' Telephone (3 lines): 3230 CENTRAL, SHEFFIELD Codes: A.B.C, WESTERN UNION, A.1. BENTLEYS, LIEBERS. ETC. THOS FIRTH & SONS, LIMITED NORFOLK WORKS SHEFFIELD London Office: 8 THE SANCTUARY, WESTMINSTER S.W.1. Telegraphic Address: 'MESMERIC. PAR. LONDON'. Telephone Number: 8510 VICTORIA. Handwritten: 4429 IN YOUR REPLY PLEASE QUOTE Spring DEPT. JWF. August 25th, 1923. Messrs Rolls Royce Ltd, DERBY. 40/50 h.p. SPRINGS. Dear Sirs, With reference to the experimental sets of Springs which we supplied for the above, and which were fully discussed when Mr Stansfield and the undersigned had the pleasure of calling upon you on Friday, the 17th inst, we duly received one pair of our manufacture and one pair of companion Springs manufactured by Messrs Woodhead, which were returned to us for carrying out load tests etc. You informed us at the meeting that the difference in performance of these Springs when mounted on a car and tested on the road, varied considerably. The Springs of our manufacture appeared to increase the rolling action and were too flexible, and it was thought the cause was probably due to the smaller amount of internal friction in our Springs due to less nip. We have now had an opportunity of very carefully testing these Springs on our machine, and we enclose load diagrams wherein it will be noted that the amount of friction is not greatly different on the two rear Springs, and that what difference there is is in the opposite direction to that originally supposed, namely, that the internal friction of our Springs is greater than Messrs Woodhead's. Our rear Spring gives about 9.7% difference between the up and down load at the mean load, whilst Messrs Woodhead's gives about 7.4%. These differences represent the combined effect of the friction opposing movement in the up and down direction. The tests were first carried out on the Springs in exactly the condition as received from. As we thought that this might be effected by the cleanliness and lubrication between the leaves, we dismantled the Springs and carried out a complete re-test. These, however, gave practically the same results in the same Continued. | ||