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 plotting back pressure in inches of mercury against engine RPM for different silencer configurations.
| Identifier | ExFiles\Box 104\2\ scan0066 | |
| Date | 19th 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 R P M, 10, 5, 1000, 1500, 2000, 2500, 3000, 3500 | ||