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).
Summary of information and data regarding crankshaft torsionals for B.60 and flat 12 cylinder engines.
| Identifier | ExFiles\Box 132\2\ scan0184 | |
| Date | 9th December 1940 | |
| To: Ev.{Ivan Evernden - coachwork} c.to JNR.{Charles L. Jenner} Wd.{Mr Wood/Mr Whitehead} Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} 1116 Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}1/ET.9.12.40. CRANKSHAFT TORSIONALS FOR B.60 AND FLAT 12 CYLINDER ENGINES This is divided into two parts. A.{Mr Adams} Information asked for in Rm.{William Robotham - Chief Engineer}8/ML.26.10.40. 1. The amplitude of the 6/rev.vibration of the flat 12 cyl. engine. 2. The range over which it might be expected to extend. 3. Whether any of the other harmonics would cause trouble. 4. Whether a flat 12 cyl. 2-stroke would be worse with regard to the 6/rev. vibration. 5. The separate effects of gas and inertia on B.60 torsionals. 6. The fundamental frequencies of 12 cyl. and 6 cyl. crankshafts. B. An appendix is attached containing data necessary for the above information. This is added not because it makes interesting reading, but because such data does not appear to be in our files. The following curve sheets are attached: Sheet 1. Flat 12 cyl. 4 stroke torsionals for an engine of Phantom III size. 2. Flat 12 cyl. 2 stroke torsionals for an engine of Phantom III size. 3. B.60 torsionals based on a constant m.e.p. of 120 lb/in2 4. B.60 torsionals with the gas component based on an m.e.p. curve. 5. B.60. The separate effects of gas and inertia torque. 6. M.E.P. curve used in the torsional calculations. NOTE Sheets 3 & 4 show that the error incurred by assuming a constant m.e.p. is small up to the 3½/rev. vibration. | ||