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).
Graph comparing back pressure in different silencer configurations against engine RPM.
| Identifier | ExFiles\Box 179b\2\ img027 | |
| Date | 10th October 1932 guessed | |
| BACK PRESSURE IN SILENCERS - No SWAN NECK & FISHTAIL III ① RESONANCE SILENCER ② STANDARD 20/25 SILENCER ③ NO SILENCER (BACK PRESSURE DUE TO MANIFOLD DOWNTAKE FRONT EXP BOX) BACK PRESSURE INS HG ENGINE RPM 5 10 1000 1500 2000 2500 3000 3500 | ||