Modifications to the 'Thumper' design, altering it into a 'BM.40'.
| Identifier | ExFiles\Box 109\3\ scan0027 | |
| Date | 30th October 1940 | |
| -2- Jnr. {Charles L. Jenner} 9/JH.30.10.40. The bulk of this work is the Thumper design unchanged, and the modifications and alterations making it into a BM.40. are clearly indicated on the various schemes. Jnr. {Charles L. Jenner} [Signature] Original to Rm {William Robotham - Chief Engineer} /HH. Prints to Rm. {William Robotham - Chief Engineer} Ev. {Ivan Evernden - coachwork} Rm {William Robotham - Chief Engineer} /HH. Ashby. | ||
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).