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).
Establishing standard dimensions for pistons for the 20-HP engine, including two diagrams.
| Identifier | ExFiles\Box 66\1\ scan0143 | |
| Date | 11th July 1927 | |
| ROLLS-ROYCE (FRANCE) LIMITED (Reversed) Mx{John H Maddocks - Chief Proving Officer}/T/11.7.27. Before definitely establishing the dimensions thus arrived at as standard, we would like say six sets of pistons to be produced to the following dimensions which incidentally will give approx. the same proportionate clearances as we now have on the 20-HP. engine. Incidentally although latterly we have very little trouble with the 20-HP. engine, we find a similar distortion takes place to a lesser degree. Left Piston: 4.246 DIA -1 4.249 DIA -1 Right Piston: 4.235 DIA. -2 4.242 DIA. -2 Mx{John H Maddocks - Chief Proving Officer} [Signature] | ||