Connecting rod failures in Eagle engines, discussing potential causes such as forging defects and ongoing material tests.
| Identifier | ExFiles\Box 42\2\ Scan009 | |
| Date | 28th March 1918 | |
| R.R. 235A (500 T) (S.D. 408. 28-4-17.) Bm. 2/156/13. Contd. -2- EH1/LG28.3.18. material, there is .25" of metal all over to be machined off. We agree that there is a possibility of longitudinal cracks because on one of the Experimental engines sometime ago we had rods fail on which longitudinal flaws were quite distinct, but those rods ran for 200 hours before they failed. We do not see how it could possibly be the design. There are now over 1,500 Eagle(Aero Engine) engines in service and every week about 40 to 50 Eagle(Aero Engine)s including repairs are tested at the works. We should soon hear if rods were breaking in service. Since writing the above another engine has failed on test, in this case there is no doubt that it is the connecting rod which failed first, there is also no doubt that the metal where it was fractured is in a bad state possibly due to it being burnt in the forging. The forgings for the Eagle(Aero Engine) connecting rods are made outside the works. Attached herewith is Mr. Hall's report on the composition and condition of the material. Although this last failure is undoubtedly due to a flaw in the connecting rod material it does not provide a reason of the previous fractures. We have now 2 N.S. rods and 2 C.V.S. rods break. We are pushing on with the rods for test. Mr. Hall is also carrying out tests on test pieces to see what harm can be done to N.S. by overheating and forging at too low a temperature. EH. attc. | ||
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).