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).
Page discussing speedometer calibration, axle ratio changes, gearbox oil sealing, and various vacuum tank fittings.
| Identifier | ExFiles\Box 19\3\ Scan118 | |
| Date | 23th December 1929 guessed | |
| - 8 - All speedometers are made to indicate the correct speed when shaft rotates at 1008 revs. per mile, and it is customary in this country to base this speed on the nominal diameter of the tires, which gives a reading about 5% high when actual rolling diameters of tires are considered. Changes in axle ratio or wheel size are taken care of by changing the no. of teeth in the driven pinion A-10728 and when this is done it is necessary also to change the gear centers by boring the cover A-9770 in a different place. Up to now we have found it possible to use the same casting to take care of all variations. The helical groove on the drive spindle A-12924 and drain in the Bearing A-12925 are necessary to prevent oil from creeping up the shaft from the gearbox as the venting of the gearbox is not always sufficient to take care of this. Vacuum Tank Fittings - Straight through unions. A-8825 Arrgt. of Vacuum Tank. A-9082 Tower Wheel and Ring Assy. A-9084 Tower Ring. A-8602 Vac. Tank Fitting. A-8860 Gas Feed Elbow. A-8861 Restricted Suction Elbow. E-50615 Nipple. A-8008 Union Nut. This is the standard Stewart Warner Vacuum Tank with a few refinements such as polished Nickel Silver Cover, "aterite" (monel metal) float and monel metal pins specially for us. Note restriction in suction elbow. We enclose print of nipple to show our standard practice of tapering hole for pipe, so as to fit at bottom and allow good space to get solder or brazing metal in at end. At the time this was used, elbows were made of M.S. - at a later date all steel fittings on the petrol line were changed to some form of stainless. Vacuum Tank Fittings - Banjo Type Unions. A-10690 Vacuum Tank Fitting. A-10700 Banjo Connection. A-10699 Gas Feed Plug. A-10758 Restricted Suction Plug. - continued - | ||