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).
Photograph of the Spontan transmission and brake fitted to an Essex Super Six engine.
| Identifier | ExFiles\Box 41\4\ Scan035 | |
| Date | 21th September 1931 guessed | |
| The Spontan transmission and brake as fitted to a 55 b. h.{Arthur M. Hanbury - Head Complaints} p. Essex Super Six engine. | ||