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).
Torsional stiffness measurements for a Bentley III frame with varying hole configurations.
| Identifier | ExFiles\Box 86\4\ scan0241 | |
| Date | 3rd May 1939 guessed | |
| Bentley III frame. .128" thick. With 2 plain holes in gussets and 0 holes in side members 1450 lbs. ft. / degree - 10 0 1400 - 10 6 1360 - 10 lipped 6 1400 | ||