The planes have an aspect ratio of eight and measure two inches in depth by sixteen in width. The outer ends of the rear plane are three inches in their fore and aft dimensions, thus making the outer rear edge a slight concave. The front is cut sharply away at an angle of forty-five degrees. The upper plane lies flat upon the motor base. The lower plane is not set directly below it as in the ordinary biplane form, but to the rear, its front edge being on a line with the rear edge of the upper plane, after the manner of the Valkyrie machine. The two planes are separated by a space slightly greater than their width. Two small rudders, elliptical in shape, are carried just behind and below the rear plane. The model is mounted on very delicate skids built of reed, and is inclined at a very slight angle. Six strands of one-eighth-inch rubber are used for each motor. The unusual length of the motor makes it possible to give six hundred turns.
An ingenious method of lightening the front end of the motor base and at the same time reducing the head resistance is employed in the Burgess Webb model. A single stick frame is used with a base equal to one-fourth its length. The cross piece is mortised to the central stick and braced by the diagonal sticks, joining at the main frame. This cross piece is carried out beyond the braces and pierced for the propeller shafts, where two twin propellers are mounted. Fig. C.
The front plane is elliptical in form, with a width equal to two-thirds the width of the base. It has an aspect ratio of two. The propeller motors are strung on hooks attached to the outer sides of this frame. The plane must be unusually strong to stand the pull of the motors, which is naturally great. It is fixed to the extreme outer end of the central stick. The main plane, which is mounted well forward in this model, is an almost perfect semicircle. One can, of course, carry out his own ideas in selecting the design of the planes.
A very light central stick is used which is strengthened by wires running to a vertical strut at the center. It is claimed that the ingenious arrangement of the forward plane cuts away from one to two ounces in the weight of the model, and the decreased head resistance adds both to its stability in flight and distance qualities. The simplified form of front plane may be adopted on a variety of models.