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).
The examination and failure analysis of two experimental 20 HP Front Springs.
| Identifier | ExFiles\Box 52\2\ Scan240 | |
| Date | 6th August 1930 | |
| ALL COMMUNICATIONS TO BE ADDRESSED TO THE COMPANY. Codes ABC WESTERN UNION A1 BENTLEYS LIEBERS ETC THOS FIRTH & SONS, LIMITED NORFOLK WORKS SHEFFIELD Telegraphic Address: 'FIRTH SHEFFIELD' Telephones: NORFOLK WORKS SHEFFIELD 23031 TINSLEY WORKS ATTERCLIFFE 41193 Location Office: 8 THE SANCTUARY, WESTMINSTER, S.W.1. Telegraphic Address: 'MESMERIC PARL. LONDON' Telephone Number: 8310 VICTORIA YOUR REFERENCE: Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} 3/MJ. OUR REFERENCE: DEPARTMENT SPRING DEPT. PHONE EXTN. T.33. HWP/AR/649. August 6th 1930. Messrs. Rolls-Royce Ltd., Nightingale Road, D E R B Y. Dear Sirs, With regard to your letter of July 10th concerning two experimental 20 HP Front Springs, tested by you with a view to service for certain special types of bodies. We report as under the results of our examination of the following plates:- Spring No.1. (A) Bottom Plate. (B) Top Clip Plate. Spring No.2. (A) Main plate. (B) 2nd. plate. (C) Top Clip Plate. Plate 1B had fractured through the oil-hole, the fracture being of the fatigue type. Plate 2C had fractured in a similar manner to Plate 1A. In plate 2B the fracture occurred immediately above the fracture in plate 2C, and in the main plate 2A, the fracture was displaced a little to one side of the fracture in the underlying two plates. The fracture of this plate was not of the brittle type, but it evidently had received a bend of about 30° before fracture had occurred. We are of the opinion, therefore, that the first failure occurred in the top clip plate in each case. These springs are highly stressed. Under the normal load the range of the stress in the main plate is 34 tons per sq. in. and the mean range of stress in the whole spring is 30 tons per sq. in. The bend test shows that there is a fair amount of ductility present in all the springs. Continued. | ||