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).
Letter to Claude Johnson regarding engine performance, comparing Siddeley engines to a piston valve design.
| Identifier | ExFiles\Box 126\4\ scan0009 | |
| Date | 3rd June 1910 | |
| Claude Johnson, Esq. (2) 3rd June 1910. The engine itself had been very good and silent. LOLS.18 H.P Several Siddeleys chirp quite badly considering how small the engines are; - side by side valves, plugs over valves. In our piston valve engine I placed the plugs just where I have since learned that they are best. Yours sincerely, | ||