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).
Request to modify the 21-G-IV exhaust system by fitting a larger expansion box and modifying the rear silencer.
| Identifier | ExFiles\Box 104\2\ scan0116 | |
| Date | 5th November 1934 | |
| X5230 To RHC.{R. H. Coverley - Production Engineer} Hs{Lord Ernest Hives - Chair}/Wym.{G. Harold Whyman - Experimental Manager}7/KW.5.11.34. 21-G-IV Exhaust System. Will you please build up and fit to the above car a front expansion box to Hs.{Lord Ernest Hives - Chair}1436, i.e., 4.500" outside dia. (present one fitted is only 4.250" dia.), and modify the rear end of the rear silencer to Hs.{Lord Ernest Hives - Chair}1514. These modifications bring the exhaust system right up to date. Hs{Lord Ernest Hives - Chair}/Wym.{G. Harold Whyman - Experimental Manager} | ||