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 engine vibration amplitude against RPM for different spring drive and damper configurations.
| Identifier | ExFiles\Box 124\1\ scan0089 | |
| Date | 22th April 1939 | |
| B 60 WITH WRAITH SPRING DRIVE SET AT 19 LBS AT 17 1/2" WRAITH III WITH WRAITH SPRING DRIVE SET AT 15 LBS AT 17 1/2" B 60 WITH B 60 DAMPER SET AT 219 LBS FT/DEGREE AMPLITUDE DEGREES ENGINE R.P.M. JRS. 22. 4. 39. | ||