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).
Test report on a modified intermediate gear bush for a Kestrel engine supercharger due to issues with the white metal lining.
| Identifier | ExFiles\Box 179\2\ img119 | |
| Date | 30th April 1935 | |
| ORIGINAL x2965 Re. From Hs{Lord Ernest Hives - Chair}/YAG. c. to Sor. c. to Sy. c. to Mr. Jaques. Hs{Lord Ernest Hives - Chair}/YAG.S/14.S.1. 30.4.35. SUPERCHARGER DRIVING SHAFT - R.28354/1 KESTREL INTERMEDIATE GEAR. Trouble has been experienced with the White metal lining of the standard intermediate gear bush R.28254 failing in the bore at the flanged end. The attached sketch shows that these bushes are fed with oil from the plain end. It was suggested that the oil was thrown from the flange faster than it could pass along the bore of the bush, the diametrical clearance on the gear spindle being only .0015". This diametrical clearance could not be increased as more float in the gears would be undesirable. In order to supply a positive oil feed to the part of the bush giving trouble, three equally spaced slots .050" wide, .015" deep and .575" long were cut in the bore of the bushes. To prove out the modification the supercharger of Kestrel - 11 S - 27 was built up with the special bushes incorporated (Memo ref: Hs{Lord Ernest Hives - Chair}/YAG. 1. 31.18.12.31.) Conditions of Test. Engine Kestrel - II S - 27 with special a/c bushes R.28354/1. Oil Silvertown P. 4. Oil Press (Main 60 lbs/sq.in. (Auxiliary 7.5 lbs/sq.in. Oil Temperature (Inlet 50°C (Outlet 77°C The engine was run for 8 hours at 2250 r.p.m. under the above conditions. On stripping the supercharger all the bushes were in excellent condition there being no signs of scoring or of any tendency to pick up. There were however slight hard marks at the ends of the grooves which are considered to be due to the fact that the groove is square cut on the end and that the metal is lifted slightly during the machining of the grooves. A further modification has now been made to the bushes. This consists of blending the ends of the grooves into the bore instead of cutting them off square. | ||