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).
Dynamo brush failure and transmission rattle on a Goshawk-11 car, with internal comments on solutions.
| Identifier | ExFiles\Box 46\2\ Scan200 | |
| Date | 21th April 1922 | |
| x4086 Hotel de L'Ouest, Laval, France. x4219 x4086 21.4.22. EP.{G. Eric Platford - Chief Quality Engineer} from Hy.{Tom Haldenby - Plant Engineer} Hs.{Lord Ernest Hives - Chair} and I arrived here from Le CanadelHenry Royce's French residence on Tuesday night last since when we have been working on 8-Goshawk-11 getting it ready for carrying on 10,000 miles. The dynamo failed due to the brushes wearing out until the dynamo springs came down on to the brush holder terminals. Hs.{Lord Ernest Hives - Chair} says the brushes are morganite copper carbon and that they are not satisfactory - the Le Carbone ones being better. The brushes have certainly worn unduly and the end cover and the commutator were thick with the carbon dust. The commutator was also rather badly worn. We have cleaned up the machine and bent the brush springs so as to carry on until the correct brushes which I wired for arrive. We have also thoroughly lubricated the chassis and found that the universal joints of propeller shaft required quite a lot of grease. Since doing this the rattle in the transmission which was very bad, has practically disappeared and the car is now as good in this respect as the 4/5-Goshawk-11. We will say more of this when we have run the car more. We are of the opinion that the noise originated in the sliding joint of the propeller shaft. Unless the universal joint has ample lubrication the sliding portion may not receive sufficient lubricant. We suggest that you try running a car with this joint dry to see if the rattle can be reproduced. On all Goshawk cars there is some vibration on retard and it may be this vibration which causes an underlubricated joint to rattle. 8-Goshawk-11 has been running 350 miles or more each day and I will let you know the actual mileage in next report as the log book is now out on the car. The miel mileage approx. is 9000. OUR COMMENTS. Two sets of Le Carbone brushes were sent to Hy.{Tom Haldenby - Plant Engineer} as requested. R.{Sir Henry Royce} is also recommending Le Carbone brushes in preference to morganite and we propose to use this type of brush on all Goshawk experimental cars. We also consider that the brushes could be made longer to advantage so as to allow much longer life. We find that the Le Carbone brushes are inclined to be more noisy than the morganite. Can Hy.{Tom Haldenby - Plant Engineer} confirm this?(see later) This can be tried out on cars at the works. It may be an advantage to arrange for the serrated joint of the propeller shaft to be grease-retaining. With this front universal joint we can continue injecting grease until the propeller shaft is filled. contd:- | ||