THE LAUDER DISTANCE AND DURATION MODEL
After many months of experimentation Mr. Wallace A. Lauder succeeded in producing a model that proved to be one of his most successful models. But a few years ago flights of 1000 feet with a duration of 60 seconds were considered remarkable. But so rapid has been the development of the rubber strand driven model that to-day it is hardly considered worth while to measure a flight of 1000 feet, especially in contests where models fly over 2500 feet or 3537 feet which was the distance flown by Mr. Lauder’s model during one of the contests of the National Model Aëroplane competition of 1915. Mr. Lauder’s model on several occasions made flights of over 3500 feet with a duration in each event of over 195 seconds. It is therefore to be remembered that this model is both a distance and duration model, both qualities being seldom found in one model.
Reference to the accompanying [drawing] will give a clear idea of the constructional details.
The frame or fuselage consists of two side members 40″ in length, of straight grained spruce. At the center each member is of approximately circular cross section, and is ¹⁄₄″ in diameter. The members taper to about ³⁄₁₆″ at the ends, the circular cross section being maintained throughout. The frame is braced by a strip of bamboo of streamline form, extending from one side member to the other, 18″ from the apex of the frame. The ends of this frame are bent to run parallel to the side members of the frame where they are secured by binding with silk thread and gluing. Piano wire hooks are also secured to the side members of the frame adjacent the ends of the cross brace, and from these hooks extend wires of steel (No. 2 music wire) which run diagonally to the rear brace or propeller spar where they are secured.
Diagram 11
The frame is braced further by an upwardly arched strip of bamboo, as shown in [diagram 11], this strip being 2¹⁄₂″ in height. At the top of this brace are two bronze strips of No. 32 gauge brass, one above the other, one on top of the brace and the other below.
Adjacent the ends of these strips of metal are perforations through which pass bracing wires, one of which wires runs to the front of the frame where a hook is mounted for its reception, and the other two wires extend to the rear of the frame where they are secured to the propeller brace. The propeller brace consists of a strip of streamlined spruce 11³⁄₄″ in length, the propellers being at an angle, thus clearance is allowed ¹⁄₄″ wide at the center, tapering to ³⁄₁₆″ at the ends. The ends of the propeller brace extend out one inch from the side members of the frame, to allow room for the rubber strands to be used as motive power. In order to avoid slotting the ends of the side members of the frame so that the propeller brace can be secured therein, thin strips of bamboo are secured above and below the end of each side member, by binding with silk thread and gluing, the space between these bamboo strips being utilized for the brace which is securely bound and glued therein. The propeller bearings consist of strips of very thin bronze (No. 32 gauge), about ³⁄₁₆″ in width, bent over ⁵⁄₈″ strips of German silver tubing, the tubing being soldered to the bronze strips and the propeller brace, which fits between the upper and lower portions of the bronze strips, is securely bound and glued thereto.
The propellers are cut from solid blocks of pine, and are 12″ in diameter. The blade, at its widest portion, measures 1³⁄₈″. The blades are cut very thin, and in order to save weight, they are not shellacked or painted.
The propeller shafts are of piano wire (No. 20 size) to fit the tubing used in the bearings, pass through the propellers and are bent over on the outer side to prevent turning. A few small bronze washers are interposed between the propellers and the outer ends of the tubing to minimize friction when the propellers are revolving. Twelve strands of rubber are used for each propeller, the rubber being ¹⁄₈″ flat.
Wallace A. Lauder distance and duration model
Wallace A. Lauder R. O. G. Model
The wings are both double surfaced, and are of the swept back type. The span of the main wing is 28¹⁄₂″, with a chord of 6¹⁄₂″. The elevator has a span of 15″ with a chord of 4³⁄₄″. The main wing has eleven double ribs, these ribs being built up on mean beams of spruce ¹⁄₁₆″ × ³⁄₁₆″, the front beam being placed 1¹⁄₄″ from the entering edge, and the second beam being 2″ back from the front beam. The entering and trailing edges are formed from a single strip of thin split bamboo, all the joints being made by binding with thin silk and gluing.
The elevator is constructed in like manner, except that it only has seven ribs, and the measurements are as above set forth. Both planes are covered with goldbeater’s skin, sometimes known as “Zephyr” skin, which is first glued in place and then steamed, which tightens the same on the plane, and given a coat of preparation used for this purpose.