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).
Investigation into 'Galloping Knock' on a Phantom, comparing Slipper Flywheel performance with Bakelite and cotton duck friction discs.
| Identifier | ExFiles\Box 47\2\ Scan066 | |
| Date | 24th February 1928 | |
| W.H. Hs{Lord Ernest Hives - Chair} by XC417 From Ax. Ex1/T24.2.28. "Galloping Knock" Phantom Following up the investigation carried out by the Experimental Dept. we have now had experience with similarly loaded Slipper Flywheel on six chassis. The improvement effected varied from chassis to chassis, but on an average was about 50%. Although we expected to find that the crankshaft periods would be more noticeable with the light loading, this was not the case. In four cases out of the six we used Bakelite discs, on two we were unable to obtain much improvement until we fitted cotton duck. Our experience was that to obtain the maximum improvement the loading had to be kept to very fine limits. From our past experience of Bakelite, we are of the opinion that the loading will not maintain during the varying conditions under which the car is used. We of course have not had much experience of cotton duck, but we should think owing to its absorbent nature, it is more likely to maintain the loading over periods of rest. We have always been in favour of keeping the initial poundage of slipper drives as low as possible, consistent with getting results, as it is obvious the lower the poundage the more likely is the lubrication of the friction surfaces to be maintained. In order to obtain some information as to what will happen to slipper drives after a period of standing, we have run two slipper drive units, one fitted with Bakelite, and the other with cotton duck on a chassis, the initial loading being 153 inch lbs. i.e. the poundage recommended by the Experimental Dept. The slipper drive units are now hanging up in the Test Dept. and we are proposing to let them stand for a period of say 3 weeks, at the end of that time, we shall again test the loading. Although as before stated, we have not very much faith in slipper drives with Bakelite as a friction medium maintaining the poundage within small limits, we suggest some further information on the subject might be gained if a number of chassis - say 20 were built up initially to the low poundage, so that we could carefully note their behaviour during their progress through testing. contd:- | ||