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 showing the variation of shackle angle against compression for a narrow pad.
| Identifier | ExFiles\Box 43\2\ Scan167 | |
| Date | 27th May 1926 guessed | |
| (11P). VARIATION OF SHACKLE ANGLE. Narrow Pad. 10° Inward Shackle. YI SHACKLE ANGLE. COMPRESSION IN INCHES 40° 30° 20° 10° 0 0 1 2 3 4 5 6 | ||