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).
Kestrel engine failures, including rod and lug issues, and proposed modifications such as grooved journal bearings.
| Identifier | ExFiles\Box 179b\3\ img266 | |
| Date | 17th February 1933 | |
| ORIGINAL To Rr From Hs.{Lord Ernest Hives - Chair} c. to Sg.{Arthur F. Sidgreaves - MD} -Wer. c. to Rg.{Mr Rowledge} Br.{T. E. Bellringer - Repair Manager} c. to By.{R.W. Bailey - Chief Engineer} Ir. c. to Lp.{Mr Lappin} Fl. c. to Fk. Hs.{Lord Ernest Hives - Chair}7/WJ.17.2.33. x4657. x3859. KESTREL ENGINES. Engines are now being produced with grooves in the journal bearings which should do a tremendous lot to look after any temporary shortage of oil. We think it should be realised that we have produced approximately 1,000 Kestrel engines. If we assume that 200 of these have not yet been put into service, we have had 800 engines (4,800 rods) in service. If we discount the split pin failures (2) we have had eight failures of rods in service. Six of these failures occurred in one week. Why we should have six in one week is quite impossible to account for. As they occurred in places like Belgium, Tangemere, Tollerton, Farnborough, it cannot be due to any local condition. We do have these epidemics, for instance we once had four Hypoid axles go wrong in one week, and since then we have never had another failure and nothing has been done. The Schneider engines in 1929 and 1931 ran without grooves in the bearings. The recent troubles we have had have shewn us how to improve our engines but we do not subscribe to the fact that the engines that are in service can be looked upon as unreliable. There is no doubt that the Kestrel engine is the most reliable aero engine we have ever made and the A.M. records shew that it is the most reliable engine that has ever been in service. This does not mean that we can be satisfied. It is obvious that we have a terrific struggle in front of us to maintain our position. If we assume that the grooves in the bearing are going to help us as regards failure of lubrication, then we have to go over the other weaknesses on the engine. On six or seven engines when they have come back for overhaul cracks have been found in the lugs of the forked rod. Similar cracks have also been found on development engines. We have three modifications instructed to improve this part - (1) Deeper lugs. These have been tested in connection with lead bronze bearings and high power test, and we have succeeded in breaking one of the lugs. | ||