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).
The cause of exhaust cracking noise and proposed solutions involving studs, nuts, and the downtake pipe.
| Identifier | ExFiles\Box 14\6\ Scan088 | |
| Date | 2nd July 1929 | |
| SECRET. X7220 E2/M2.7.29. Hs.{Lord Ernest Hives - Chair} from E.{Mr Elliott - Chief Engineer} Copy to Sg.{Arthur F. Sidgreaves - MD} Ry. SS.{S. Smith} EXHAUST. X7220 It is concluded that the unpleasant cracking noise from the exhaust is caused not by the manifold sliding on its joint faces but by the studs and nuts getting caught up and suddenly released. It is proposed to delete the spring washers and use two G.M. nuts on each stud, locking these nuts one against the other and giving them half a turn back or whatever is found suitable after the joint has been tightened up to partially release the load on the studs. It is also thought that longer studs and bosses might be used with advantage. Regarding the downtake pipe from the manifold to the first expansion box, we have removed the covering on 18-EX here, and intend to send through a drawing for a cast pipe on the basis that if a cast pipe is suitable for the manifold it should also be for the downtake, and at the same time be free from the troubles likely to be set up by a covered in pipe. E.{Mr Elliott - Chief Engineer} | ||