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 with different types of gears, focusing on correcting for interference and reducing hum.
| Identifier | ExFiles\Box 75\1\ scan0050 | |
| Date | 1st April 1918 guessed | |
| -7- called excellent. They were replaced in the rig and run a little longer and again tried. They were then excellent gears. We next tried a pair of planer cut standard pitch gears left soft which had not been corrected but with the interfering tips of the teeth bevelled off by hand. These were run in a standard box and were not good, but after grinding in the rig improved into first class gears from the point of view of hum. The next set of gears tried was a set of planer cut standard pitch gears not corrected but hardened. These were very poor when first tried but after grinding in the rig were very good when the box was warm but there was a slight hum when cold. At the time when I handed the experiment over to Mr Wormald we were proceeding with a set of planer cut gears of standard pitch and 17½ degrees angle, but not corrected for interference (the interference for these gears is very small). Also I had instructed some sets of 17½ degrees planer cut gears of standard pitch which were corrected for interference. It is just possible with this angle to get rid of the interference. With regard to the principle described above, it is necessary to remember that although the flywheels make every effort to run at a constant speed and so remove the undesirable metal from the teeth by grinding, yet | ||