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).
Wraith gearbox 'chunking' issues and experiments with Schatz bearings.
Identifier | ExFiles\Box 8\11\ 11-page155 | |
Date | 16th February 1939 | |
628 TO Dy.{F R Danby} c. to Hs.{Lord Ernest Hives - Chair} c. to Da.{Bernard Day - Chassis Design} c. to Hdy.{William Hardy} c. to 'S'. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}6/JH.16.2.39. WRAITH GEARBOX. L.A. is having great difficulty in getting gearboxes tolerably free from 'chunking'. Because of an experiment we did a long time ago on P.III which showed that Schatz bearings for shaft location reduced chunking, we gave L.A. a pair for the first and third motion shafts of a Wraith box. He says they are a success and wants to use them. Our experiments with Schatz bearings are as follows Wraith 1st. motion shaft. (1) Has 4 times the life of the standard bearing under dyno conditions with a 45° helix shaft. (2) Has run a rig test of 500 hours at 4,000 r.p.m. under no load and looks new (This represents top gear conditions). Since then we have reduced the helix angle of the first motion shaft from 45° to 35°. This is not good for a Schatz bearing for which it is recommended that this thrust load shall not be less than the journal load to prevent 'four-tracking'. But the most successful application R.R. have made of Schatz bearings is the crown wheel thrust in which the thrust load is only a quarter of the journal load. We have also run a Schatz bearing at the front of a B.II box for 5,000 miles without trouble. R.{Sir Henry Royce} & M.{Mr Moon / Mr Moore} are running for us a rig test under the new 35° helix conditions of which we shall know the result in about 5 days. We therefore recommend Schatz bearings with 'plit inner races for 'O' series. We will fit them to 'g's. car, Hs{Lord Ernest Hives - Chair}' car and Lx's car in addition to 25.G.VI. | ||