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).
Issues and potential solutions for an SS exhaust system, including noise, cracking, and cooling methods.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan174 | |
| Date | 1st July 1929 | |
| HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} [C.c. to SS.{S. Smith}] (crossed out) [ WOR{Arthur Wormald - General Works Manager}] (crossed out) [ DY{F R Danby}] (crossed out) ORIGINAL SECRET. R4/M1.7.29. X7230. SS.{S. Smith} EXHAUST. We are very definitely against wrapping the exhaust in asbestos, and sheeting it. If the upper piece (on engine) is silent in thick metal (cast iron), then the lower piece should be. We are sending a design for a cast aluminium first expansion box with outside ribs to help silence and cool the exhaust. Cracking noises probably come from expansion motion; deep Y exhaust should have been OK., and one cannot believe with equally thick pipes that there should have been much, if any, difference in noise. We, and others, have used sliding joints on the first pipe instead of trusting sliding faces; we are sending a few modifications. The booming of the exhaust we think cannot come through the metal of the pipes, but must depend on exit noises, hence cooling the exhaust is very desirable, as well as for the life and expansion of the parts. If the exhaust exit is too noisy we ought to work at the diaphragms. Have you tried the suggested grading of the perforations? The internal pipes in the silencer should avoid the necessity of asbestos jacket. If not, try an aluminium box at the front, and where noise may occur - see drawing. It is just worth trying water cooling the first part of the pipe, finding what percentage of radiator it takes extra. It would reduce all the above troubles, (heat, noise, expansion, and oxidation. R.{Sir Henry Royce} | ||