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 shackle angle and the other comparing spring systems.
| Identifier | ExFiles\Box 43\2\ Scan160 | |
| Date | 27th May 1926 guessed | |
| TOP GRAPH: (1) SPRING RATING TESTS (β) AND (α). EFFECT OF SHACKLE ANGLE. WIDE PADS. Y-AXIS: RATING LBS/IN. X-AXIS: TOTAL LOAD LBS. LEGEND: α - 21° FORWARD SHACKLE β - VERTICAL SHACKLE. ANNOTATIONS: WORKING, RANGE, 1100 LBS BOTTOM GRAPH: (5) SPRING RATING TESTS. (δ) AND (β) COMPARISON OF SPRING SYSTEMS. Y-AXIS: RATING LBS/IN. X-AXIS: TOTAL LOAD LBS. LEGEND: δ - NARROW PAD. 21° SHACKLE β - WIDE PAD, VERTICAL SHACKLE. ANNOTATIONS: WORKING, RANGE, 1100 LBS | ||