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).
Two graphs comparing spring rating tests, one showing the effect of pad width and the other comparing different spring systems.
| Identifier | ExFiles\Box 43\2\ Scan163 | |
| Date | 27th May 1926 guessed | |
| (5) SPRING RATING TESTS. (δ) AND (α) EFFECT OF PAD WIDTH 21° SHACKLE RATING LBS./IN. TOTAL LOAD. LBS. α = WIDE PAD δ = NARROW PAD WORKING RANGE 1100 LBS. (6) SPRING RATING TESTS. (α) AND (E) COMPARISON OF SPRING SYSTEMS RATING LBS./IN. TOTAL SPRING LOAD. LBS. α = WIDE PAD 21° SHACKLE E = NARROW PAD VERTICAL SHACKLE WORKING RANGE 1100 LBS. | ||