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).
Inter-office report on the disappointing results of the first experimental Bethune Gearbox.
| Identifier | ExFiles\Box 137\5\ scan0082 | |
| Date | 7th November 1929 | |
| RRA 25 28M 8.29 62961 X3720. INTER-OFFICE CORRESPONDENCE ROLLS-ROYCE OF AMERICA, INC. SPRINGFIELD, MASS. H#S Btn-2 Nov. 7, 1929. To: Mr. Olley From: Mr. Burton Co- Expl.Dept. Mr. Beaver Mr. Bagnall Bethune Gearbox - D-3709 I enclose herewith first Expl. Report on the Bethune Box. This we have to admit is a little disappointing. 1.stly - The gears the shop gave us were definitely over-size and no matter how much "running in" was done, could not be expected to work quietly in a box. 2.ndly - Instead of giving endwise freedom of the shafts, we are pretty well convinced that it is necessary to control the gears sideways, in what is found to be the best running position. This is confirmed by a note in the article in Automotive Industries of Aug. 31st. last, describing this box - "To insure quiet running, side play on the intermediate gear on the main shaft and the driven gear on the counter shaft can be adjusted by means of a screw collar. Adjustment of several thousandths of an inch is provided." There is no indication of this on the original print, so we can only assure that Reo ran into the same trouble as we did. 3.rdly - The ease of changing gear was not improved - the only advantage that might be claimed, being that the noise produced when you do make a mess of changing, is not so harsh, nor has the volume that one gets on a stand-ard box. We have now in course of production, a second gearbox, differing from the first one by - (a) All helical gears made of 3-1/2 N.S. of brinell 311-331 machined after heat treatment. This is to assume ourselves it is not gear distortion causing the noise. Further we have placed an order for a complete set in Nitr-alloy. - continued - | ||