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).
Details and working principles of the Floating Weight Vibration Damper for the Phantom III.
| Identifier | ExFiles\Box 93\5\ scan0134 | |
| Date | 9th February 1937 | |
| To HPS.{Horace Percy Smith - Experimental Factory Mgr} 317 E/PSN/AHF.1/MN.9.2.37. Copy to BY.{R.W. Bailey - Chief Engineer} Rm.{William Robotham - Chief Engineer} Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} Ds. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} Floating Weight Vibration Damper. Phantom III. LeC.5487. We send you herewith two prints of each of the following details:- No.off. RS.{Sir Henry Royce's Secretary}427. Floating weight. 4 RS.{Sir Henry Royce's Secretary}428. Centre Plate. 1 RS.{Sir Henry Royce's Secretary}429. Rubber Stop. 8 RS.{Sir Henry Royce's Secretary}430. Roller. 8 RS.{Sir Henry Royce's Secretary}431. Roller End. 8 RS.{Sir Henry Royce's Secretary}432. Spring. 4 The following will also be required:- D.1986. Countersunk screw. 8 with 8 standard 2BA castellated nuts. These details have been made from LeC.5487, a print of which is also attached, which shows an experimental damper for the Phantom III crankshaft. The damper replaces the friction type damper to LeC.4475, but is designed to require no modification to the crankshaft or camshaft drive. It works on the floating weight principle as has already been used on certain American aero engines, and depends for its damping effect on the swinging of the weights. They swing in an arc whose radius has been calculated to give 6 oscillations of the weights per revolution of the crank, and therefore the cyclic torque they exert tends to oppose the 6 order harmonic of the engine torque curve. The damper should reduce the effect of this harmonic throughout the speed range of the engine, and not only during the resonant period of the crank, and increase in engine smoothness is therefore expected. As the pendulum length of the weights is only .0875" it should be realised that very accurate positioning of the roller holes and machining of the holes and the rollers themselves is essential. In order to prevent the weights causing noise when the engine is turned over slowly, rubber stops and support springs have been fitted. The damper should also be tried without the stops, but if they are found essential the use of synthetic rubber to prevent the oil attacking them should be considered. | ||