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).
Letter from Adamant Engineering Company discussing gear specifications, efficiency, and offering sample parts.
| Identifier | ExFiles\Box 28\2\ Scan176 | |
| Date | 2nd May 1933 | |
| Messrs. Rolls-Royce Ltd. Contd 2. a 1" pitch Cam giving a helix angle of 11° 18 mins. and an average gear ratio of 12.45 to 1, and the other with 15/16" pitch where the helix angle is 10° 42 mins. and the average gear ratio 13.2 to 1. We note that with the "O" Gear on the Phantom car the 1.1/32" pitch gives the best results, and we would like to take this opportunity of stating that with this pitch, in accordance with our own calculations the helix angle comes out at 10° 15 mins. and the average gear ratio at 16.25 to 1, as against your two figures of 10° 25 mins and 17.5 to 1 respectively. We also note that you give the efficiency of the Marles-Weller Gear as about 50%, but we think that when this gear is properly run in, the efficiency will be found to be considerably higher than this, although we are not suggesting it will reach as high as the figure of 75% quoted for your Worm and Nut Steering. We shall be very pleased to put you through a sample steering either of our "O" type or of our "J" Type, or if you wish, one of each, the sample being supplied to you on the same basis as before. With a "J" gear, however, on account of the smaller outside diameter of the outer tube support, a filling ring would have to be brazed or soldered either on the outside diameter of the column support, or on the inside of the 2" tube to carry a tube of this diameter. We shall also be very pleased to send you alternative Drop Arms of any length you wish, if you will be good enough to let us have particulars of set, if any, these Drop Arms being machined at the top end to fit the serrated taper rockershaft on our Gears. We look forward to receiving further particulars and instructions from you, after you have had an opportunity of discussing this letter. Reverting to the first paragraph of your letter, we shall be only too pleased to come up and discuss any points with you at your convenience. Again thanking you, and assuring you of our best attention at all times, We are, Yours faithfully, for ADAMANT ENGINEERING COMPANY Director. | ||