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 effects of oil shortage on lead bronze bearings during high power tests.
| Identifier | ExFiles\Box 179b\3\ img255 | |
| Date | 17th February 1933 | |
| Original R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Yng. c. to Sg.{Arthur F. Sidgreaves - MD} c. to Hor. c. to Rg.{Mr Rowledge} c. to L. c. to Ry. x 2965 2859 Hs{Lord Ernest Hives - Chair}/Yng.6/MA.17.2.33. THE EFFECT OF SHORTAGE OF OIL ON LEAD BRONZE BEARINGS. The high power tests which are now in progress on Kestrel II S 25 using Lead Bronze bearing material in conjunction with the plain and forked rod assembly have shewn that as far as test bed conditions go Lead Bronze is a great improvement on white metal. As a line of investigation in the proving of Lead Bronze the contingency of bearings running short of oil for a period had to be given consideration since it is known that during certain manoeuvres of an aircraft oil pressure is lost. Tests were carried out on Kestrel II MS 93 which had been fitted with the big end bearing blocks E.40477 -- Top Half, E.33478 - Bottom Half, lined with H.R. Lead Bronze. The procedure adopted was to make 50 imaginary rolls in an identical manner to those reported on in Hs{Lord Ernest Hives - Chair}/Yng.2/KT.31.1.33., using this test as the basis of comparison. In the course of the current test the engine ran a total of 37 mins. under load without oil for individual periods extending to 45 secs. duration. When stripped all the bearings were in perfectly normal condition except No.1 big end. This had, on the inside a dull greyish mark about 3/16" wide running over the complete periphery of the bearing. It is considered that this mark was a definite sign of distress as it was identical with the marks exhibited on Lead Bronze bearings which have been run with insufficient clearance and have been near to failing. The greyish marking is caused by the lead in the bearing separating out, this being a feature of failures with Lead Bronze. | ||