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).
The recommended timing settings for BTH and Watford aero magnetos.
| Identifier | ExFiles\Box 43\4\ Scan264 | |
| Date | 7th March 1930 | |
| X4021. 7.3.30. X 3832. X 4021. BTH. & WATFORD AERO MAGNETOS. Recommended timing :- M.{Mr Moon / Mr Moore} B. A.{Mr Adams} -5 95 R.{Sir Henry Royce} 55 155 --- --- --- B.T.H :- A.{Mr Adams} 7 108 R.{Sir Henry Royce} 65 168. --- --- --- Watford :- A.{Mr Adams} 16 100 R.{Sir Henry Royce} 78 160 --- --- --- | ||