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).
Design and operation of the Phantom II Low Inertia Crankshaft Damper for K.2B series and onwards.
| Identifier | ExFiles\Box 63\4\ scan0104 | |
| Date | 3rd January 1930 | |
| To Hm.{Capt. W. Hallam - Head Repairs} From Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} For Depot Sheet. X4499. For prints see other copy. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson}1/MJ.3.1.30. X7010. X4499 PHANTOM 11 LOW INERTIA CRANKSHAFT DAMPER. K.2B. SERIES AND ONWARDS. (1) OBJECTS OF DESIGN AND RESULTS ACHIEVED. It has been found that as regards engine smoothness and absence of crankshaft vibrations, the best results are obtained with the minimum flywheel weight on the nose of the crankshaft. On previous designs the hub for the slipper wheel has always been rigidly fixed to the nose of the crankshaft. The object of the present design is to remove the inertia of this slipper wheel hub from the shaft and use it as part of the flywheel for damping vibrations. The effect of this alteration in construction is to improve the high speed smoothness of the engine and to eliminate crankshaft periods more effectively. It also eliminates the "galloping knocks" which are at present sometimes found on the cars when picking up round about 20 m.p.h. An added advantage is that the slipper wheel is less susceptible to variations in the poundage at which it is set. (2) CONSTRUCTION AND METHOD OF OPERATION. Reference to the attached diagram will shew the method of construction of the new crankshaft damper. This consists essentially of the light plate 'A', which is the only portion of damper rigidly fixed to the nose of the crankshaft. The inertia plates carrying the friction lining 'B' are mounted on journal bearings on the shaft and would be free to rotate independently of the shaft were they not constrained by the springs 'H'. The springs 'H' flexibly couple plate 'B' to the plate 'A'. The total spring control movement being 'K', and amounting to some 4° either side of the central position. When the crankshaft vibrates, the nose only moves through about 2° and therefore damping can take place between the friction surfaces and the plate connected to the crankshaft without hitting the stops. (3) EFFECT ON TIMING. Method of Timing. It will be observed that the crankshaft timing pinion 'D' is rigidly connected to the inertia plate 'B'. The inertia plate 'B' is connected through springs and dogs 'N', 'M' to plate 'A' and so the crankshaft. When the engine is turned over by means of the starting handle, the springs will be compressed and the timing will momentarily be altered | ||