A TAPLEY PERFORMANCE CALCULATOR
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THE well-known Tapley meter provides the user with the actual pull exerted by his vehicle, measured in lb. per ton ; it does not, however, tell him what the figure ought to be. To perform the latter function, Tapley and Co., Belvidere Works, Totton, Southampton, has now introduced a mechanical calculator, which takes into consideration gross weight, engine capacity, gear ratio and wheel diameter, and gives the maximum pull of which any machine should be capable.
This is read off from either a topgear hill-climbing scale or a scale marked for top-gear acceleration on the level and lower-gear hill-climbing, whilst the speeds between which the full torque is developed are also shown. The weight-scale is graduated up to 100 'cwt., but, by setting the pointer to half the actual gross weight and appropriately correcting the result, we have obtained figures which correspond fairly closely with the performances revealed by a number of our road tests.
Other applications of the calculator -are to ascertain the engine r.p.m. from the road speed, the pull in one gear from that known in another, the rate of acceleration in m.p.h. per second and the time taken to accelerate from 10 m.p.h. to 30 m.p.h.
Furthermore, the capacity and weight scales can be used as an ordinary slide rule. The price of this well-made instrument, which should appeal to designers and testers, is 3s. 6d.