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).
Blueprint of a double resonance unit designed to be fitted onto a pipe.
| Identifier | ExFiles\Box 14\6\ Scan245 | |
| Date | 22th April 1932 guessed | |
| HS{Lord Ernest Hives - Chair} 558 2 CLIP INSIDE LENGTH 10.00 INSIDE LENGTH 4.25 1.5 DIA 3.42" EXISTING E.79332 EXISTING E.79333 EXISTING 3.000 A 4.00" 4.7" 7/8 DIA INSIDE CLIP ALL FLANGES DRILLED AS ON PREVIOUS SILENCER DOUBLE RESONANCE UNIT TO BE MADE SO THAT IT CAN BE SLID ALONG PIPE E.79333 TO FIND THE MOST EFFECTIVE TUNING POSITION ON ITS LENGTH FOUR ADDITIONAL FLANGED SLIDING PIECES A TO BE MADE SO THAT THE CONICAL BAFFLES PREVIOUSLY MADE CAN BE UTILISED | ||