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 20/25 HP car exhaust system, including an analysis and back pressure tests of a Cadillac silencer.
| Identifier | ExFiles\Box 104\2\ scan0024 | |
| Date | 2nd June 1932 | |
| y5230. To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}6/KT.2.6.32. 20/25 HP. CAR EXHAUST SYSTEM. X1276. Further to our report ref. Hs{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey}2/MA.2.6.32, on the 20/25 HP. resonance type silencer. We have had a Cadillac silencer analysed by H1. in the Laboratory, and the following is his report - "The material of which this is built up is ordinary mild steel sheet, similar to specification 2 39A. The centre tube is on the hard side of this specification while the remainder is on the soft side. The outer coating consists of aluminium, apparently put on by spraying." We have also taken its preliminary back pressure tests, a copy of which we attach. The tests were carried out on a P.II. engine, as it happened to be available. The results show the standard high compressioned Phantom would gain to the extent of 5 HP. with this silencer over the standard one, but that with these free silencers we shall want a freer swanneck, as the back pressure in the whole silencer is only 8 lbs/sq.in. at 3000 r.p.m. and the swanneck then puts on a further 4½ lbs/sq.in. This test is merely a preliminary one to show that in addition to weight and cost, we are also going to gain in efficiency. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} The Cadillac silencer which is being handed to you was actually invoiced to us at a price of less than 4 dollars and we think that the suggested construction is not appreciably more complicated than theirs. | ||