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).
Engineering test procedure for a skid pad test on the chassis, detailing side thrust calculations and plotting results.
| Identifier | ExFiles\Box 155\4\ scan0061 | |
| Date | 1st March 1939 | |
| E.R. 51. 216 VAUXHALL MOTORS LIMITED SCHEDULE No. H1 SHEET No. 5 ENGINEERING TEST PROCEDURE CHASSIS SECTION SUBJECT Skid Pad Test Procedure ( Continued. SIDE THRUST. Side thrust would be directly proportional to the weight and to the square of the speed except for the drainage slope of 9" in 120 feet. towards the centre. Side thrust = W (V² cos S - Sin S) / g R in which W is the weight, R is the radius of the circle = 108 ft. V is the speed in feet per second, g is 32.16 and S is the angle between the pad and the horizontal. Side thrust being an accelerating force can be expressed as per cent of the accelerating force of gravity ( g). PLATE VIII. MILES PER HOUR. SIDE THRUST. % OF g.{Mr Griffiths - Chief Accountant / Mr Gnapp} 5 .009W .9 10 .055W 5.5 15 .133W 13.3 20 .242W 24.2 25 .380W 38.0 30 .551W 55.1 PLOTTING RESULTS. Specimen graphs for right-hand and left-hand turns are shown on sheets 11 & 12. The curves of steering angle ( front wheels) and steering wheel angle differ to an extent which demonstrates the "wind-up" in the steering gear. The former are plotted from the average reading of the two front-wheel indicators. Roll angle and attitude angle curves are plotted from the theodolite readings. The front slip angle curve is plotted from results calculated as already described. As shown, all these angles are plotted against lateral acceleration expressed as a percentage of gravitational acceleration. The relationship between this percentage, and the speed maintained on the skid pad circle, is as shown on sheet 14. Signed........... A.E.Cooke Dated........... Feb.1939 Approved........... M.Olley Mar 1939 | ||