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).
Ignition plug testing, materials, and specifications.
| Identifier | WestWitteringFiles\D\March1920\ Scan26 | |
| Date | 29th March 1920 | |
| from R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} ORIGINAL RB{R. Bowen}/C27/3/20. 29 1920 X.3905 RE IGNITION PLUGS. The ignition plugs sent have not passed Mr. Hives' test. Try and find out what does best at Service Station, and send other samples to Derby. We have lately proved that porcelain insulation is preferable to mica, as slight carbonisation burns off the hot porcelain. We use central heavy pure nickel electrode, and multi-points reaching out of base towards it. These are capable of adjustment, and slow running is best obtained by these set at .035" plus or minus .003 for battery ignition. R.{Sir Henry Royce} | ||