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).
Continuation page discussing the design, testing, issues, and virtues of a crankshaft damper system.
| Identifier | ExFiles\Box 111\3\ scan0085 | |
| Date | 27th April 1939 | |
| -5- Rm{William Robotham - Chief Engineer}/Swd1.2/MR.27.4.39. CRANKSHAFT DAMPER - Cont'd.{John DeLooze - Company Secretary} fact but definitely proven on tests carried out on Wraith. The whole object of the adaption of the Wraith spring drive is in insulating the camwheel from the crankshaft oscillations to prevent failure of the camwheel teeth which has occurred regularly with the solid drive and harmonic damper. The camwheel in question is of "Attwater" pine fabric, the same material as used on Wraith III. The complete damper was mounted external of the wheel case and a considerable amount of work was carried out to overcome an oil leak past the Acme thread. Throwers, catchers and alterations to the thread were tried without complete success and these tests made led us to the conclusion that the close proximation of the damper flywheels to the wheelcase was creating a vacuum at the thread. The leak was eventually cured by creating a depression in the crankcase by means of a pipe from the extractor breather to the air intake which registered a 3" H2O depression in the crankcase at 4000 R.P.M. But for the ugly pipe, we consider this represents a very good system and possesses the following virtues:- (1) Is more effective than the normal speed extractor in producing a crankcase depression. (2) Curing of oil leaks tending past the rear bearing and the front end. (3) Complete fresh air circulation through the crankcase which is now widely advocated, the air inlet to the engine being through a hole in the rocker cover. (4) Is more baffled to prevent oil getting into the intake by the passage in the filler, which on several of our late models when taken from the rocker cover presented a real difficulty and eventually abandoned for this reason. | ||