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).
Test report for a 10-leaf spring, detailing Brinell hardness and endurance test results.
| Identifier | ExFiles\Box 80\2\ scan0226 | |
| Date | 7th October 1920 | |
| X.2628 X.1331 BUMPER TEST. X.2628 F.5629 Spring consisting of 10 leaves, tapered ends, with nibs and slots and tie clips. Fitted to N.S. Bump chassis 29.9.20. No. of leaves. | Brinell. | Remarks. | Time run. --- | --- | --- | --- 1 | 477 | O.K. | 2 | 415 | O.K. | 3 | 415 | O.K. | 4 | 363 | O.K. | 5 | 415 | O.K. | 33 hrs. 55 mins. 6 | 429 | O.K. | 7 | 444 | Broken under front clip. | 8 | 429 | | 9 | 444 | Broken under rear clip. | 10 | 429 | | Taken off 7.10.20 | ||