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. A MODEL WITH ADJUSTABLE STABILIZERS. A serviceable model may be built up with flat planes equipped with ailerons both at the rear and outer ends of the planes. These tips make it possible to control both the horizontal and vertical movement, and permit a great many adjustments impossible with other models. The motor base may be borrowed from some earlier model. It should be fairly heavy. A rectangle measuring ten by forty inches built of one-half inch strips will be found sufficiently rigid. The sides should be braced by a cross piece at the middle. The ends and central strut may be made of some form of truss, if desired. One of the simplest means of providing supports for the axles of the propellers is to carry the stick at the rear, one and a half inches beyond the side pieces, and pass the axle through a hole drilled one-half an inch from the end. [Illustration: A Model With Adjustable Stabilizer.] The pull of the motors when wound is thus well distributed and, as has been pointed out, permits of a larger propeller being used without danger of their striking in turning. Still another advantage is that it keeps the strands of the motor from interfering with the planes. When the motors are strung above the planes, they have a tendency to force the machine downward.