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 detailing the results of a bumper and 12-leaf spring durability trial, including Brinell hardness tests on the broken spring.
| Identifier | ExFiles\Box 80\2\ scan0172 | |
| Date | 1st July 1920 | |
| X2628 BUMPER TEST. Spring with 12 leaves O.S. F.4666 - 2000 lbs. N.S. F.4665 - 2226 lbs. Date. Total hrs. Remarks. 24.6.20 25.6.20 7 hrs. 45 mins. Bolt and cap K.419 broken O.S. centre main bearing bracket. 26.6.20 28.6.20 29.6.20 30.6.20 1.7.20 35 hrs. 40 mins. Bolt broken centre main bearing bracket O.S. K.419. 1.7.20 36 " 45 " leaf Bottom O.S1 broken 5" from rolled eye. Front diagonal stay broken close to cross member. BRINELL TESTS OF BROKEN SPRING. 1st. 415 O.K. 2 444 " 3 495 " 4 495 " 5 444 " 6 461 " 7 461 " 8 415 " 9 444 " 10 415 " 11 415 " 12 444 & 388 where broken. | ||