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 showing the effect of swan neck diameter on a 20/25 HP resonance silencer.
| Identifier | ExFiles\Box 104\2\ scan0067 | |
| Date | 19th October 1932 guessed | |
| 20/25 H.P. RESONANCE SILENCER - EFFECT OF SWAN NECK DIAMETER. II ① SMALL DIA. SWAN NECK = 1.50" ② LARGE DIA. SWAN NECK = 2.00" ③ NO SWAN NECK B.H.P. R.P.M EXHAUST BACK PRESS. (INS. Hg.) B.M.E.P. | ||