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).
Engine issue of 'popping back' on the Phantom model, diagnosing it as explosions in the silencer.
| Identifier | WestWitteringFiles\P\July1926-September1926\ Scan106 | |
| Date | 13th September 1926 | |
| TO HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} C. to BJ. for HR. ORIGINAL PHANTOM. X8080/X93 X8230 HR. writes of "popping back". I am not sure what this means. We generally understand the term to mean "in the carburetter", but we are not troubled with this - (it is generally due to over weak mixture or bad distribution.) So, I must read it as explosions in the silencer, which we do not know how to entirely cure, but on some cars it occurs much less. Probably when bad it indicates a combination of many defects, such as throttle fitting or sticking, errors in setting of carburetter, or running with control in the wrong place. Except when the cutout is open I have not experienced it very badly. The Phantom engine having overhead valves does not fire small charges as well as pocket engine on Silver Ghost, therefore some are missed at high speed throttle nearly shut, and these are fired by the exhaust of others in the exhaust pipe. Turbulence may improve this, but the throttle should be allowed to close after high speed running, while luffing up. We ought not to be worse than other similar engines. Why is it? We have several things to help to avoid this. R.{Sir Henry Royce} | ||