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).
The results of a test on Chassis No. 7-LF to address a 'galloping knock'.
| Identifier | ExFiles\Box 65\4\ scan0247 | |
| Date | 13th January 1928 | |
| HS{Lord Ernest Hives - Chair} X8020 S/W. Wor.{Arthur Wormald - General Works Manager} Copy to:- C. H.{Arthur M. Hanbury - Head Complaints} Hs.{Lord Ernest Hives - Chair} Mx.{John H Maddocks - Chief Proving Officer} EP.{G. Eric Platford - Chief Quality Engineer} CWB31/GW/13.1.28. Re: Chassis No. 7-LF. Major Victor Walker. (Galloping knock.) -------------------------------- I think it would be useful to place on record the results of a test of this car to-day, after certain work had been carried out by Hancock of Hs.{Lord Ernest Hives - Chair} Department. This work is understood to be the fitting of a new material (cotton duck) in the slipper drive, and a reduction in the poundage of this member to 8 lbs under the standard test condition. Under these circumstances, it is found that the galloping knock previously so very noticeable on this car under practically all conditions of use is almost absent. It may certainly be detected by accelerating and decelerating across the speed at which it is most marked, with this car 20 - 21 m.p.h.; but it is considered that the alterations which have been made have certainly reduced the intensity by 85%, and in its present form it is considered satisfactory for use. In the ordinary course of driving the car the effect would probably not be detected and in cases where the knock has not been previously observed it is questionable whether any ordinary user would ever find it. At the same time, the car was later given a severe test on some high speed running, which did not appear to disturb it in any way and at the close the conditions were exactly the same as at the start. It was thought that there was rather more than a normal amount of high frequency vibration about the engine when running over 45 m.p.h. but this was not considered excessive and as the car was not previously particularly tested for this it cannot be stated that this has increased owing to the changes made. Particularly on 3rd speed at 33 m.p.h. = 1750 revs., a very definite high frequency crank shaft vibration could be observed. In any case the balance of advantages are very much in favour of the car in its present state. C. has approved of its being delivered to the owner in this form, which will be done as soon as certain small items, quietening tappets, are done, and closest touch will be kept with the CONT: | ||