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).
Valve noise tests for a single valve type damper, detailing efforts to eliminate a 'squawk'.
| Identifier | ExFiles\Box 151\2\ scan0251 | |
| Date | 19th June 1934 | |
| Hs {Lord Ernest Hives - Chair} /WB. {Mr Brazier / Mr Bell} 10/KW.19.6.34. Single Valve Type Damper. Valve Noise Tests. Whilst the fitting of the valve "hat" with a small diametral clearance effectively eliminated the "squawk" associated with the single valve type of damper, and the dampers were said to work satisfactorily under road conditions, nevertheless, the test rig indicator diagrams and bench tests revealed that this type of damper was not as controllable as desired, the presence of the "hat" being held to be partly responsible. Efforts were made to discover is possible other means of eliminating the "squawk", and to this end the following tests were taken, each being described in this report to guide the trend of future development, and if possible prevent repetition. Prior to and also following the standardisation of the "hat", the "squawk" was effectively cut out by drilling various holes in the valves, and/or fitting permanent leak washers under the valves. This method however was found to be detrimental to cornering by permitting "rolling", and to generally affect the controllability of the damper. It was found that by exeAero Enginerting a side pressure on the valve, the vibrations could be damped out, and later, by splitting the valve - i.e., separating the H.P. and L.P. sections - the required side pressure was considerably reduced. Eventually it was found that by fitting a hair spring, as shown in Hs. {Lord Ernest Hives - Chair} 1405A, the "squawk" could be eliminated. This method was objected to however on the grounds that it would induce wear, although the pressure exeAero Enginerted was very light. It had however the advantage that the high to low pressure load ratio could be varied - it had previously been ascertained that varying the effective diam. did not affect the relative initial loads in anything like the theoretical proportions. | ||