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).
Graph from a spring rating test comparing a standard spring with Woodhead's special spring.
| Identifier | ExFiles\Box 43\2\ Scan169 | |
| Date | 27th May 1926 guessed | |
| (13) SPRING RATING TESTS. (η & α) COMPARISON OF SPRINGS Wide Pads, 21" Shackles Mean Curve η = WOODHEAD'S SPECIAL SPRING α = 1st SS{S. Smith} STANDARD SPRING AXIS LABELS: Vertical: SPRING RATING LBS/INS Horizontal: TOTAL SPRING LOAD LBS. | ||