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).
Test report on the fatigue failure and subsequent engine testing of 'Little Piston' type connecting rods.
| Identifier | ExFiles\Box 10\4\ 04-page40 | |
| Date | 22th December 1939 | |
| T.S.D. [STAMPED IN RED: 29] COPY. LITTLE PISTON In view of the results of a recent rig test, when a 'Little Piston' type connecting rod failed in fatigue at a load corresponding to 4800 r.p.m. it was decided to run an engine test at these conditions. We have several sets of these rods available for test but some are only suitable for use with slipper type big ends. As we wished to test the complete rod we have therefore taken a set of rods originally intended for PV.12 and have fitted them to a 'Kestrel' crankshaft for the purpose. As the set of rods was not a matched set the weights of the reciprocating parts had to be corrected. This has been done as far as possible by altering the weight of the little ends but the variation in the big end weights has been left as it is not possible to alter these without machining the rods themselves and this was considered undesirable. The out of balance forces resulting from this variation in the big ends are very small and can be neglected. It is proposed to run this engine at 4800 r.p.m. for a short period and then to examine the rods for signs of fatigue. It is also proposed to carry out a similar test on a set of standard 'Kestrel' rods for comparison purposes. No information is available on the fatigue life of these rods at present. The assembly of the engine is proceeding at the moment. It is hoped to have the engine on test in the near future and a further report will be issued when the results are known. | ||