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 on a leaf spring's durability, noting material hardness and failure points over time.
| Identifier | ExFiles\Box 80\2\ scan0181 | |
| Date | 30th July 1920 | |
| XZ628 AS. SPRING F.363 - 2100 lbs. - parallel - tapered ends - no nibs and slots - ground all over - fitted on bump chassis 28.7.20. No.of leaves. | Brinall | Remarks. | Time run. 6 1 | 415 | cracked 1 1/2" from centre rear of clip. | 13 hrs.15 mins. 2 | 415 & 429 | broken in two places each side of clip. | 3 | 444 | cracked under clip. | 4 | 444 | O.K. | 5 | 429 | O.K. | 6 | 415 | O.K. | 14 hrs. 10 mins. Spring taken off 30.7.20. | ||