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).
Procedures for conducting weighbridge, torsion, and suspension tests on new cars.
| Identifier | ExFiles\Box 152\2\ scan0215 | |
| Date | 23th May 1940 guessed | |
| -8- WEIGHBRIDGE TESTS. Torsion Tests. These should be carried out on every new frame and as far as possible, on every new car. The test is carried out by supporting the four points of the frame in line with the wheels on rigid supports. See sketch in Frame Data file. The two rear ones should be on weighbridges, and one of the front ones should be an adjustable screw jack. If a bare frame is being tested at least 400 lbs. of sandbags should be distributed along the frame to prevent one corner lifting when raising or lowering the screw jack. The process then is to twist the frame by raising and lowering the screw jack, measuring the torque being applied by the change in load on the weighbridge, and the deflection by means of micrometer clocks on either side of the frame at intervals. A graph can then be drawn having degrees of twist as abscissae and applied torque as ordinates. For figures obtained see Frame Data file. Suspension Tests. Rating tests for both vertical movement and roll. One pair of wheels at a time is put on weighbridges, and screw jacks fastened to the floor are attached to that end of the car by any convenient means. Previously the measurements of the vertical movement of the wheels relative to the car have been taken by measuring the distance between the wing and the hub cap, but it has been pointed out that in the case of the front this is liable to error because the front wheel does not remain vertical. The measurement should, therefore, be taken between the wing and the ground, and the deflection of the tyre subtracted. Graphs are available showing the deflection rates for various tyres at various pressures. See the tyre king. Graphs can then be drawn showing the spring rating and roll rating. Also the position of the wheels relative to the stop should be measured at no load, full load, and buffer contacts as shown in the Book of weighbridge results. The weight on each wheel should be noted with driver only on board and with driver and three passengers. ----- | ||