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).
Excessive wear on valve rocker bushes in Condor III engines at Farnborough and potential design modifications.
| Identifier | ExFiles\Box 43\3\ Scan153 | |
| Date | 4th April 1927 | |
| A.{Mr Adams} M.{Mr Moon / Mr Moore} FORM 1084. AERONAUTICAL INSPECTION DIRECTORATE. MEMORANDUM. No. 35 From INSPECTOR IN CHARGE A.I.D. To Mr. Bailey. Mr. Rowledge. Mr. Platford. Mr. Hives. Mr. Grimmer A.I.D. Date April 4th, 1927. (9626). Wt 11352-10829 500. 10/24. T.S. 128. Ref:- W/HB{C. E. Harcombe}/E.3. CONDOR III ENGINES AT FARNBOROUGH. Last week I visited Farnborough in connection with reports of excessive wear of valve rocker bushes. Farnborough have been running two engines recently, S.C.90 which has done 45 hours in a machine (Berkeley) and S.C.48 which has done 98 hours on the bench. With the engine in the machine, trouble was experienced owing to the tappets requiring continual adjustment, and after a time this was found to be due chiefly to excessive wear in the bushes carrying the valve rockers. The two worst boxes I have brought back with me for you to see. The engine on the bench has run twice as long as the other, but the wear is nothing like so serious, although it has commenced. Farnborough suggest that the trouble is due to the oil for the bushes having to follow a fairly intricate path; when machines are standing with the tails down, any oil in the camshaft runs out at the back end and it takes a little time for the shaft to fill up again, so that there is a period when there is no oil supply to the bushes. With engines on the test bench which are in the horizontal position, this tendency of the oil to drain away is not so marked, and therefore, there is always a little oil to commence with, and this explains why the bench engine does not wear so quickly as the other. Farnborough suggest that the design needs modifying so that the bore of the camshaft remains filled with oil when the engine stands, by means of a lightly loaded valve in the end of the camshaft, or some other means. Will you please let me know if you have had reports of this trouble from elsewhere, and if you are in agreement with Farnborough's suggestions. A.I. For D.D.I.I. | ||