Page C2                   March 1936            NEWNES PRACTICAL MECHANICS      331 

Detailed Blueprints will be Issued for a Nominal sum.

 Legal Requirements 
In the absence of proved designs, the beginner may make expensive mistakes. There are the legal requirements, for example, which stipulate that brakes must apply to each wheel, and that there must be an independent hand-brake ; the head lamps, in order to satisfy the Lighting Act, have to he mounted at a certain height from the ground and not more than a certain distance in from the extreme outside line of the vehicle. The number plates and the figures and letters theron, must be to legally prescribed dimensions, and a silencer must he fitted. The machine must not be noisy. Those are just a few of the legal requirements. The mechanical requirements are a little more detailed. We have to bear in mind the loading per horse-power so that the engine does not labour. The steering angle needs to be worked out for wheel clearance, and provision must be made for cooling the engine. The gear ratios must be carefully selected, so that the engine is  enabled to rev. at its peak revolutions in order that it may develop maximum power.The chassis must he free from whip, otherwise there would he frequent breaking of chains and undue wear on the transmission and tyres. The suspension System needs to he just right in order to absorb road shocks. The centre of gravity needs to he accurately disposed, so that the machine is stable and does not turn over, and the driver's seat needs to he disposed approximately midway between the two points of road support. Hence., the amateur who endeavours to design his own car finds this array of technical and legal considerations disconcerting.