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).
Gear eccentricity, tip clearance, and helix accuracy for silent gearing in the Phantom III.
| Identifier | ExFiles\Box 136\5\ scan0310 | |
| Date | 31th August 1937 | |
| [REDACTED] [REDACTED] [REDACTED] C. Rm.{William Robotham - Chief Engineer} Engines. [REDACTED] 115^2 BY.6/C/31.8.37. F T H SILENT GEARING. G.82925. Further to BY.6/C.31.8.37. the amount of eccentricity between the gear and the hub, which it is mounted on, should be .150. This will produce a tip clearance on the side shaft gear in the Phantom lll box of .0003. This amount of tip clearance, or increase of "barrel" for curvature, is possibly on the high side, but it is a figure that we should try and produce a gear to in the first place in order to run same under load and ascertain whether the clearance is too much. The clearance in question will have to cover tooth deflection as well as oil film thickness when the oil is cold. In regard to the question of producing an accurate helix, I am arranging to issue another memo in the form of an instruction that the helix must correspond with a train of gears, in other words it must be accurate and not an approximation. I would like to emphasize here that this is only applied to one gear in a pair. In the case of the timing gears it would have to be the camshaft wheel which carried the correction. By.{R.W. Bailey - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} | ||