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 testing of two different 13-leaf bumper chassis springs.
| Identifier | ExFiles\Box 43\2\ Scan032 | |
| Date | 21th July 1921 | |
| HS{Lord Ernest Hives - Chair} X4558 (crossed out) X3900 REPORT ON BUMPER CHASSIS SPRINGS. F.4633 U.S.A. Spring consisting of 13 leaves with tapered ends, nibs and slots, tie clips. 1100 lbs. Fitted to N.S. Bump chassis 21.7.21. No.of leaves. Brinell. Remarks. Time run. 1 429 Broken across centre bolt hole. 23 hrs. 20 mins. 2 429 Broken across centre bolt hole. 26 hrs. 3 429 Broken across centre bolt hole. 26 hrs. 4 401 O.K. 26 hrs. 5 415 O.K. 28 hrs. 20 mins. 6 429 O.K. 28 hrs. 20 mins. 7 429 Broken across centre bolt hole. 28 hrs. 20 mins. 8 429 Broken across centre bolt hole. 28 hrs. 20 mins. 9 444 Broken across centre bolt hole. 28 hrs. 20 mins. 10 429 O.K. 28 hrs. 20 mins. 11 429 O.K. 28 hrs. 20 mins. 12 415 O.K. 28 hrs. 20 mins. 13 444 O.K. 28 hrs. 20 mins. F.4633 U.S.A. Spring consisting of 13 leaves with tapered ends, nibs and slots, tie clips - 1155 lbs. Fitted to O.S. Bump chassis 21.7.21. 1 444 Broken across centre. 56 hrs. 56 mins. 2 444 Broken across centre. 61 hrs. 21 mins. 3 401 O.K. 61 hrs. 21 mins. 4 415 O.K. 61 hrs. 21 mins. 5 363 O.K. 61 hrs. 21 mins. 6 444 Broken across centre 57 hrs. 56 mins. 7 415 Broken across centre 57 hrs. 56 mins. 8 415 Broken across centre 57 hrs. 56 mins. 9 387 Cracked. 57 hrs. 56 mins. 10 413 O.K. 61 hrs. 21 mins. 11 413 O.K. 61 hrs. 21 mins. 12 429 Broken across centre. 61 hrs. 21 mins. 13 444 Broken across centre. 61 hrs. 21 mins. | ||