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).
Design of exhaust pipes, focusing on materials, thermal expansion, and potential design improvements for the 25HP model.
| Identifier | WestWitteringFiles\V\March1931-September1931\ Scan096 | |
| Date | 4th March 1931 | |
| E.{Mr Elliott - Chief Engineer} HS.{Lord Ernest Hives - Chair} ) FROM R.{Sir Henry Royce} BY.{R.W. Bailey - Chief Engineer} ) (At Le CanadelHenry Royce's French residence.) C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} P. 1. EXHAUST PIPES. ORIGINAL R4/M3.4.31. X8230 I may be quite wrong but these have not been designed as I expected - not simple enough. I do not see why we need join the two centre bends together and why we fit detachable nozzles. Enclosed find scrap drawing of simple treatment that seems to have equally good chance of being satisfactory. The front exhaust pipe should be long enough and flexible enough to do no harm; anyway the spherical joint appears to have little advantage unless it is left slack. Can we get any better cast iron which is strong when it is hot? The sliding joint will bind up by the inner part getting hotter than the outer: I can only suggest ample clearance and maximum length. The alternative treatment E.{Mr Elliott - Chief Engineer} suggests is ribs to strengthen and keep cooler. This might be successful but I understand that our sliding joint type was quite good on Silver Ghost. We must remember that we have more powerful engines now and that owing to its large size we cannot make parts as strong as smaller cars relatively, and our troubles of expansion are greater, but the 25HP has not this excuse: it is equally urgent. Try both cars with both sliding and rib type, because the latter is easier and less costly. I did not remember that present exhaust manifold was all in one piece - i.e. joined together in centre. Make only for one type, say the cast iron head until tested if successful, then use this system for aluminium head and 25HP. R.{Sir Henry Royce} RECEIVED 4A APR 1931 SH | ||