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 failures in Goshawk engines during high-output power tests.
| Identifier | ExFiles\Box 179b\3\ img332 | |
| Date | 14th March 1933 | |
| [STAMP] ORIGINAL To R.{Sir Henry Royce} From Hs.{Lord Ernest Hives - Chair}ar. c. to Sg.{Arthur F. Sidgreaves - MD} W.F. c. to R.{Sir Henry Royce} E.{Mr Elliott - Chief Engineer} c. to Sy. EF. [HANDWRITTEN] X4688 GOSHAWK ENGINES. VALVE FAILURES UNDER HIGH OUTPUT CONDITIONS. We have recently carried out a series of high power tests on engines fitted with Goshawk superchargers, for the purpose of proving various types of connecting rods and bearings. These tests have mainly consisted of running for periods of 10 to 12 hours under Special Category endurance test conditions of the Kestrel engines fitted with Goshawk blowers, which consists of 891 BHP. at 2750 R.P.M. using special fuel 20/70/10 plus 4 cc's. (Av/Ben/Meth) and Castor P.2 oil. In each case, the tests, although initially for the purpose of testing the rods and bearings, have terminated owing to an exhaust valve failure. The initial failures were at first attributed to the valve material which was S/SLT. salt cooled, so the material was changed to H.R.Crown salt cooled, but the trouble still persisted and from observation the failures generally occurred after 5 to 6 hours running, with either steel. During the latest high power tests for the DES.1828 curved foot rods, which were carried out on Kestrel 25 engine with Goshawk blower, it was decided to make special observation of the valves as regards stretching and warping, and the engine was stopped after each 2 - 3 hour period to check clearances but no indication of diminishing clearances was observed. After running for six and a quarter hours the exhaust from No.5H. cylinder showed excessively hot, which is the indication of valve failure, and on investigation it was found that the front exhaust valve of that cylinder had failed. The clearance was checked almost immediately and was found to be maintained at .020" The specific fuel consumption during the test was similar to the previous tests of this description, i.e. .530 Pts/HP/Hr. | ||