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).
Schedule of spring tests comparing different types based on road and bump test failure rates.
| Identifier | ExFiles\Box 72\3\ scan0126 | |
| Date | 12th September 1924 | |
| Schedule. For enclosure with CJ3/E12/9/24. SPRING TESTS. Type of Spring. | Road Tests. | Miles run before failure. | Bump Test. Hours run before failure ---|---|---|--- Standard 40/50 HP | Paris report failures in ordinary usage on French roads. | 5,000 | 12 20 HP Goshawk | R.R. road trials in France. | 5,000 | - 25% stiffer. 40/50 HP with F.W.B. | R.R. road trials in France. | 13,000. 17,000. 19,000. | 18 12.5% stiffer 40/50 HP with F.W.B. | R.R. road trials in France | 6,200 6,990 | 15 12.5% stiffer Woodhead spring top plate .285'' thick. | | | (1) 23 hours (top plate) (2) 22 hours (bottom plate) 27 hours (2nd and third plate) top plate still intact | ||