To meet this desire all that it is necessary to do is to make a chassis, or carriage, which can be secured to the frame of the model, and with extra power added, will result in a practical R. O. G. model. In constructing such a chassis or carriage it is necessary to bear in mind that it must be made sufficiently strong to withstand the shock and stress which it will be called upon to stand when the model descends to the ground.
For the main struts of the chassis two pieces of bamboo each 9″ in length are needed and these should be bent over 1″ on one end as shown in thediagram, that they may be fastened to the under side of the frame members, one on either side, at a point on that member 12″ from the front. Two similar pieces of bamboo, each piece about 7″ in length, are required to act as braces between the frame membersand the main chassis struts. Each end of each of the braces should be bent over in the same direction and in the same manner as that described for the main strut so that the fastening to the main frame member and the main chassis strut may be accomplished. Steam may be used in bending the ends of the pieces of bamboo. To make the landing chassis sufficiently stable to withstand landing shocks a piece of bamboo 9″ should be fastened from either side of the main chassis struts at the point where the chassis brace on either side meets with main strut. The ends of this cross brace should be bent in similar fashion to the other braces to enable its being fastened easily and securely.
Two small wheels constitute the running gear for the front part of the chassis, for which two pieces of ¹⁄₁₆″ steel wire each 2¹⁄₄″ long are required. These small wires are fastened to the bottom ends of the main struts, and to accomplish this the wire should be bent in the center at right angles; one leg of the angle isattached to the bottom end of the main strut as shown in thediagram. Disks for wheels may be cut from a bottle cork which should be ³⁄₄″ in diameter by approximately ¹⁄₄″ in thickness. The edges should be rounded off to prevent chipping. Before mounting the wheels on the axles which have been provided by the wires attached to the bottom of the main struts, a piece of bronze tubing ³⁄₃₂″ inside diameter and ³⁄₁₆″ long should be inserted in the center of each disk. To secure the least possible resistance on the revolutions of the wheels, there should be placed on the wire axles pieces of bronze tubing similar in diameter and ¹⁄₈″ in length on either side of the wheel (see illustration). When the wheel is thus placed in position with the pieces of bronze tubing on either side about ¹⁄₄″ of the axle wire will extend from the outward end of the outside piece of tubing. This should be bent over the tubing to prevent its falling off and at the same time hold the wheel securely in position.
For the rear skid a piece of bamboo 6″ longis used, one end of which is curved as in a hockey stick so that it will glide smoothly over the ground. The other end of the rear skid should be bent over about ¹⁄₂″ so that it can be securely fastened to the propeller braces, as illustrated in thediagram. Two 7″ pieces of bamboo are required to act as braces for the rear skid. Both ends of each brace strut are bent over ¹⁄₂″ in the same direction, one end of each strut is securely fastened to a side member 3″ from the rear and the other end of each strut is fastened to the rear skid, at their point of meeting as shown indiagram 9, the method of attaching being the same as in the case of the forward portion of the chassis. All joining should be accomplished by first gluing the braces and then binding with thread. When completed, the rear skid should glide along the ground in bobsled fashion, thus preventing the propellers from hitting the ground.