Page:Popular Science Monthly Volume 89.djvu/90

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��Popular Science Monthly

��balancing an aeroplane, there is no time lo lose. The huge machine is treacherous because its great inertia makes it apparently stable. But once it yields a little, it tries obstinately to yield more. The necessarily wide distri- bution of weights around the center of gravity aggravates this inherent ten- dency. In the light of these considera- tions the idea of using biplane-ailerons on the first huge land aeroplane recently tried in this country seems interesting, a frank confession that stronger con- trols are needed, although an excess of head resistance at the wing tips, and ob- jectionable leverage are the price paid for this improvement. The frame that holds the wheels has been strengthened by shortening it, which is made possible by raising the propellers and motors (to clear the ground) although the total length of framing remains the same. There is an advantage in having the lower plane thus laterally brace the length at the point it does. Otherwise the wheels themselves appear weak for a total weight of over two tons and the mass of open framework supporting the motors has undue head resistance; it has the excuse that the motors may thus be brought further ahead to increase the leverage and staljilizing effect of the tail.

��The weak elevator contrasts strangely with the powerful ailerons and the double \crtical rudder.

To find out what reall\- lia|)[)ened to the wrecked "Super-America," we must read the testimonjof the tugboat cai)tain who happened to see the accident at close range. The flyers were given no time for observations. Eye-witnesses tell of a propeller working loose and an "ex- plosion" that scattered small fragments Ix'fore the plunge came. The mere loss of a propeller and the racing of an engine should not jeopardize stability. Prob- ably the pilot, bewildered l)y the injury to the power plant and handicapped by relatively weak controls, failed to coun- teract some air disturbance.

The machine also was only one hundred feet up, too close to the water for righting a small monoplane, let alone a dreadnought. The "somersaults" be- fore reaching the water testify to an "America's" lack of stability resulting from lack of le\erage between the stabilizing planes and the principal weights which are not concentrated enough and not large enough in pro- portion to the amount of momentum. All long-hulled flying-boats suffer from such a lack of leverage, with no practical solution in sight.

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���On a recent trip from Wasliington to Newport News this •■Super-America" fell. killinR two

passengers and injuring three. So rigid was its structure that axes could not break through

in the effort to extricate the victims

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