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 results for engine performance under four different exhaust system configurations.
| Identifier | ExFiles\Box 93\1\ scan0004 | |
| Date | 8th October 1934 | |
| Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}23/KW.8.10.34. (1) Complete SpectreCodename for Phantom III System. R.P.M. B.H.P. M.E.P. Back Press. Ins. Hg. 4250 102.3 42.6 20.2 4000 118.3 52.3 20 3500 142.7 72.2 19.2 3000 140.2 82.7 16.5 (2) Silencer removed, leaving expansion box & inter.pipe. 4250 161.6 67.3 2.4 4000 176.1 77.9 2.3 3500 185.0 93.5 2.0 3000 173.1 102.2 1.7 (3) Manifolds only, front exp. box & downtake pipe removed. 4250 162.5 67.7 4000 178.8 79.1 3500 186.3 94.3 3000 174.4 102.8 (4) Manifolds removed and short stub pipes to each port. 4250 169.3 70.5 4000 185. 81.8 3500 192. 97.1 3000 179.3 105.7 Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||