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).
Test report on an experimental Spectre exhaust system and proposals for modifying the silencer.
| Identifier | ExFiles\Box 93\1\ scan0007 | |
| Date | 5th December 1934 | |
| To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} 8494 323 Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}4/KW.5.12.34. SpectreCodename for Phantom III Exhaust System. Here is a test of the Experimental system fitted to the SpectreCodename for Phantom III. Actually on the road this was very nearly 100% for booms and fish tail noise. It will be seen from the figures that though we have restricted the silencer itself too much, we have reduced the losses in the fish tail and swan neck considerably. We now propose to see how much we can open out the main silencer without spoiling the silence of the car. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||