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).
Summary of running tests on duralumin connecting rods and a decision to abandon further development.
| Identifier | ExFiles\Box 85\3\ scan0081 | |
| Date | 1st April 1934 | |
| FOR FILES X214 April, 1934. DURALUMIN CONNECTING RODS. Attached is a summary of the running we have done on light alloy connecting rods. There is no doubt that we have obtained sufficient information to know - (1) That the light alloy is a reasonably good bearing material on a hardened shaft. (2) That the weakness in the rods we have tested has been in the cap and it would not be difficult to strengthen them at this point. In view of American experience, however, in which they found it necessary to use a steel cap to prevent tightening on the shaft in extreme cold, we have decided to abandon intensive development work for the time being and concentrate on proving out lead bronze bearings in our standard rods, thus following U.S.A. practice. If we get a cold chamber that will deal with really low temperatures, we shall be able to reproduce American conditions and establish the accuracy of their conclusions. In the meantime we shall keep a set of light alloy rods running in Lp{Mr Lappin}'s car to determine the effect of fatigue on the material. Handwritten note 1: GRY{Shadwell Grylls} Please add note to say how much the critical speed is raised by using light alloy rods only (not coupled with light flywheel) Handwritten note 2: The use of dural rods raises the maxls period by 200 rpm from 5000 to 5200 rpm. This was checked by the sound of the half period on the test bed. | ||