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 low frequency vibration correction for a B.60 No 2 Wraith Spring Drive.
| Identifier | ExFiles\Box 124\2\ scan0065 | |
| Date | 12th March 1940 guessed | |
| B.60 N<u>O</u> 2 WRAITH SPRING DRIVE CORRECTED FOR LOW FREQUENCY VIBRATION ENGINE R.P.M AMPLITUDE DEGREES FIG. 2 RH{R. Hollingworth}/J.R.S | ||