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).
Experiments and testing of Maag gears for the gearbox.
| Identifier | ExFiles\Box 137\5\ scan0063 | |
| Date | 23th March 1921 | |
| CC Mr. Nadin Mr. Bagnall Mr. Hulley Mr. Southern X4365 Oy10 - C23321 March 23, 1921 Mr. Claude Johnson, Managing Director, Rolls-Royce Ltd., London, England. Attention: Messrs. Royce & Hives. Dear Sir:- X4366 Re: Maag Gear In reply to Mr. Hives' inquiries as to our experiments on ground gears for the gear box, we have experimented with six sets of those gears on the 3rd speed drive and the constant mesh gears. The constant mesh gears for this purpose were cut straight 8 pitch and 30 and 50 teeth. The 3rd speed gears were standard pitch and standard number of teeth. The gears were ground after hardening. The results have not been entirely satisfactory. Three sets were not passable. One of these was fitted in a car and was found to give a high thin skrieking noise. The other two sets were turned down on the test bench because of improper bedding and a clicking noise which came from the gears every two or three revolutions, due to some undiscovered eccentricity in the pitch line. One of these rejected sets showed that the teeth were bedding improperly, the bearing being hard near the tops of one gear and near the roots in the other gear. This was found to be due to the fact that a large radius had been left in the roots of one of the gears. There are three sets at present in the shop which have not been tested. One set when assembled in the gear box was exceedingly silent - more so, we think, than any cut gear we have heard; and the other two sets were thought to be passable. None of these three sets has been placed on chassis test however. The Pratt & Whitney Company are at present making up three sets of Maag Gears (unground) for our trial. These will be complete sets for all the gears in the gear box. We will report on the behavior of these as soon as they are received. | ||