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 torsional vibration amplitudes at critical speed for the Goshawk and Phantom models without external damping.
| Identifier | WestWitteringFiles\P\October1926-November1926\ Scan105 | |
| Date | 10th November 1926 | |
| TORSIONAL VIBRATIONS COMPARISON OF VIBRATION AMPLITUDES AT THE CRITICAL SPEED ON PHANTOM & 20 H.P. WITHOUT ANY EXTERNAL DAMPING PLAIN LINE GOSHAWK. DOTTED LINE PHANTOM. AMPLITUDE OF VIBRATION DEGREES. CRANK ANGLE DEGREES. ROLLS-ROYCE, LIMITED PRINT ROOM, 10 NOV 26 | ||