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).
Modifications to oil pumps for Phantom and 20/25HP models to reduce noise.
| Identifier | ExFiles\Box 149\2\ scan0036 | |
| Date | 14th January 1931 | |
| (2) Phantom I and II. Oil Pumps have always been a source of trouble. In the course of assembly, the remedy has been to file teeth until some improvement in the noise has been effected, but this method has resulted in the lowering of the speed at which the period occurs, and the efficiency of the pump has been sacrificed. We therefore recommend that all existing pumps should be fitted with a reservoir having a capacity of one cubic inch(16.4 c.c's). and for future pumps the casing should be made:- but before this modification is put into production, we wish to prove that this will be quite satisfactory. In the assembly of pump the present standard annular clearances of .0005" to .002", and the standard end clearances of .0045" to .0075", should be maintained. It will be found necessary, when the reservoir is fitted, to shorten the suction pipe, and it may be necessary to set the undershield to give the clearance required. This point, however, will be dealt with by D.O. The 20/25HP. Oil Pumps do not suffer from this fault, mainly because the gears are of a small diameter and out of range of the critical speed. Some time ago, a bow spring type of relief valve was tried experimentally and similar troubles occurred, which may have been caused by this type of valve and accentuated by the pump. We are now reviving the 20/25HP. type of valve referred to, as Hs.{Lord Ernest Hives - Chair} considers this should be further investigated in view of the results obtained on Phantom, so that information may be placed on record, which will be dealt with in a subsequent report. We would recommend that, in order to meet immediate needs in the Test Dept. and elsewhere, 36 reservoirs of the type referred to, should be put in hand. This will give the D.O. time to issue the necessary instructions and Works to put into manufacture. Will you therefore please confirm that this should be done. RHC.{R. H. Coverley - Production Engineer} | ||