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).
Exhaust boom issue and drone at 30 m.p.h. on chassis GUL-1.
| Identifier | ExFiles\Box 93\1\ scan0058 | |
| Date | 26th November 1936 | |
| S/W. Rm.{William Robotham - Chief Engineer} c. to Sg.{Arthur F. Sidgreaves - MD} c. " Hs.{Lord Ernest Hives - Chair} c. " BY c. " E.{Mr Elliott - Chief Engineer} Exhaust Boom - GUL-1. Cx{Major Len W. Cox - Advertising Manager}1/KW26.11.36. Rm{William Robotham - Chief Engineer}/Wyml/R21.11.36. Thanks for Rm{William Robotham - Chief Engineer}7/R20.11.36 with enclosure ref. I should like to assure you that it was not only after we fitted the extension pipe to this car that the 30 m.p.h. exhaust drone was noticed. As a matter of fact the chromium plated end piece was only put on during Show time, whereas you will find that I have referred to the exhaust noise of this car long before then. It was actually referred to in the Minutes of the Chassis Conference at W. dated 4th September. If, as you say, you found it very difficult to detect the boom when the extension piece was removed and the exhaust system restored to standard condition, will you please let us know why you have found it necessary to fit another extension piece having a flattened end [redacted] of a type which we were told we must on no account fit to the 25/30 exhaust pipe ? From a brief trial in the West End there appears to be no evidence of the exhaust drone now at 30 m.p.h., but we are giving the car a more extended test so that it shall be tried for this under all conditions of temperature, etc. Cx.{Major Len W. Cox - Advertising Manager} | ||