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).
Test specifications for the Wraith Ripple Unit No.2, detailing governor curves and flywheel advance settings.
| Identifier | ExFiles\Box 168\3\ img224 | |
| Date | 13th July 1939 | |
| To Rm{William Robotham - Chief Engineer}/EC. from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} or Bx/ED.{J. L. Edwards} WRAITH RIPPLE UNIT NO.2 FOR 12.B.V. CHASSIS 15,000 MILES. The above unit now on test has a compression ratio of 6.3 : 1 and the governor curve required is as follows:- (a) ENGINE RPM. FLYWHEEL ADVANCE. 250 Start TDC setting. 500 5° 1000 12° 1500 20° 2000 27° 2500 32° - Maximum This curve assumes that the governor starts at 250 R.P.M. if, however, the governor will not start until 500 R.P.M. then a static setting of 5° BTDC will be necessary and the following governor curve produced. (b) ENGINE RPM. FLYWHEEL ADVANCE. 500 R.P.M. Start. 1000 " 7° 1500 " 15° 2000 " 22° 2500 " 27° Maximum When this unit is returned to the shop the governor should be obtained and the characteristic made to curve (a) is possible, if not, curve (b). Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} Rm.{William Robotham - Chief Engineer} | ||