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 caused by a plated extension piece on a 25/30 HP car.
| Identifier | ExFiles\Box 104\2\ scan0257 | |
| Date | 21th November 1936 | |
| Rm.{William Robotham - Chief Engineer} Rm{William Robotham - Chief Engineer}/Wyml/R.21.11.36. EXHAUST SYSTEM. We have just had an instance of a 30 M.P.H. exhaust boom being brought up by the fitting of a plated extension piece at the end of the tail pipe. The car in question was a 25/30 H.P., Chassis No. GUL-1, and with the extension piece fitted the boom was certainly objectionable, but without it quite passable. The cause of the trouble was, that the extension piece being a plain tube fitted over the outside dia. of the existing tail pipe had a larger bore dia. than the tail pipe, and this we know from experience is very critical with regard to booms. Will you please note, therefore, that any future extension pieces should be "sleeved", so that after fitting over the tail pipe the internal dia. should be the same as that of the tail pipe. Rm{William Robotham - Chief Engineer}/G.H. Whyman. | ||