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).
Unexpectedly high propeller shaft thrust and proposing design modifications or alternative joint systems to mitigate it.
| Identifier | ExFiles\Box 179b\1\ img070 | |
| Date | 14th September 1932 | |
| HS.{Lord Ernest Hives - Chair} BY E.{Mr Elliott - Chief Engineer}) FROM R.{Sir Henry Royce} BY DA.{Bernard Day - Chassis Design}) C to CCT. WOH. ORIGINAL R5/M14.9.32. Ku.84. PROPELLER SHAFT THRUST. We were always alive to the fact that there was a propeller shaft thrust, but never assumed it to be destructively vigorous. It now appears from investigation that it may be much higher than anticipated - (awaiting confirmation.) The serrations provided for the movement we had arranged to be of large diameter and oil retaining. To this we should like to add that they ought to be nitro-hardened and lapped after hardening to a decent bedding, or at any rate arranged so that they cannot bind in the corners, in fact, the corners might be definitely relieved without cutting too much of the surface away. If we cannot reduce this pumping end pressure to a harmless amount we shall have to try to find another system of telescopic joint in which the torsional drive is taken by balls or rollers arranged to give much less end pressure. Some preliminary designs for such a device should be got out to see if we can cover by patent a scheme of telescopic joint which will avoid this destructive end pressure. It will be remembered that the gearbox 3rd. motion bearing in our older standard boxes is a very substantial one, and is likely to stand a very heavy end pressure without any trouble. In discussing this matter with HS.{Lord Ernest Hives - Chair} he pointed out that possibly this same end pressure caused some of the failures of the back axle pinion thrust bearing which have been more troublesome than should have been from the reaction of the gear. One can also imagine that this same end pressure may have considerable influence on the whirling of the propeller shaft which mysteriously comes below the theoretical speed. If this could be tested at once in a state free from end pressure, and shew any different results, it may have important bearings, and not force us to make the alterations arranged. R.{Sir Henry Royce} 424 | ||