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).
Results of a bumper test conducted on four different pairs of front road springs.
| Identifier | ExFiles\Box 43\2\ Scan248 | |
| Date | 21th April 1928 | |
| X3900 To BY/Cgh.{W Clough} from Hs{Lord Ernest Hives - Chair}/AJL. Hs{Lord Ernest Hives - Chair}/AJL1/LG21.4.28. X3900 X4429 X.8772 ROAD SPRINGS - BUMPER TEST. With reference to your BY/Cgh{W Clough}1/G17.4.28 and BY/Cgh{W Clough}14/G16.4.28 , we have sent into the despatch Stores to await your instructions re. the despatch to Firths the four pairs of broken front springs which we have tested on the bumper test - viz: 1 pr.{Percy H. Rose} T.S.F. design springs. 1pr. Chinese American springs. 1 pr.{Percy H. Rose} made to instructions on American sheets. 1 pr.{Percy H. Rose} American made springs. We have sent to HL. a piece of each broken leaf from the above springs correctly labelled as requested. The remaining portions of the fractured leaves are still built up into their own springs now in the Despatch Stores; these springs are clearly labelled. The American made springs failed as follows :- N.S. spring 1170 lbs. initial camber 3 21/32" broken after 26 hrs. 45 mins. Top 2nd. 3rd. 4th. 5th. and 6th. leaves broke. O.S. spring, particulars unknown, broke after 20 hrs. 55 mins. Top leaf only. Hs{Lord Ernest Hives - Chair}/A.J.Lidsey. | ||