Communication discussing crankshaft torsional period and brake thumps, detailing tests and proposed solutions.
| Identifier | ExFiles\Box 11\4\ 04-page042 | |
| Date | 7th May 1932 | |
| X7941. G.W.Hancock, Hotel de France, Chateauroux(French test region), Indre, FRANCE. From Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} 4/MJ.7.5.32. Thank you for your report of May 5th. Crankshaft Torsional Period. We think you should try a load of about 22 lbs. on your dampers in France, to see if you run into bus knocks. The load should remain constant because the unit pressure on the 40/50 friction discs of this poundage is less than on the 25 HP. friction discs at the existing standard setting. We have been running the brass wire Ferodo friction discs on 18-G4 here and are disappointed in the wear which takes place on the central plate. We are getting some Ferobestos discs as we think that these are less likely to cause this trouble. Brake Thumps. We have carried out some tests on the 25 HP.. We find that if we take the dashpot and fit it up as shewn in the attached sketch we produce rear brake thumps instead of front brake thumps. We then find that rear brake thumps can be completely removed by 15 lbs. friction on the swinging arm. We find that front brake thumps are reduced by altering the 'T' lever also shewn in the attached sketch. The object of altering the 'T' lever is to make the travel for the front and rear brakes approximately equal. We are now trying to make the dashpot stop brake clanks and also damp the front brakes at the same time by making it act in both directions. We shall be sending you out some parts for the carburetter during the next day or so. Hs {Lord Ernest Hives - Chair} /Rm. {William Robotham - Chief Engineer} | ||
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).