Bill Barnes Air Adventurer, July 1935 — page 118: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

116 BILL BARNES Both propellers are run by the same motor, the right-hand propeller being in front, the left-hand in the rear. Mounting the wing to the tubular fuse- lage is easily done by first cementing it to a rounded piece of balsa the shape of the outside of the motor tube, then attaching to the fuselage with rubber bands. The weight rule of 1 ounce per 50 square inches of wing area applies to fuselage as well as stick models. Since weight handicaps a model, designers are continually trying to increase lift with- out being required to increase wing area. The solution of thts problem seems to be a model patterned after the large- size Burnelli transport. The model shown in drawing #£5 has a fuselage shaped like an M-6 airfoil. The calcu- lated wing area is 200 square inches, making the required weight 4 ounces, but the fuselage also contributes to the lift. Fortunately the rules don’t include airfoil fuselages in calculating area, so the 200 square inches of fuselage area don’t raise the total weight of the ship. In other words the wing loading is actually about 1 ounce to every 100 square inches or one half the require- ment of the rules. The model is equipped with a four- bladed propeller turned by two rubber motors connected by gears. The outside gear wheels are slightly larger than the gear on the propeller shaft. This speeds up the propeller and increases duration. The big advantage of this type of gear- ing, however, is the use of two small motors instead of one large one. motor with a few strands .can be wound many more turns than a heavier motor. Gears in models are almost as old as the model-hobby itself. About 1920, the well-designed models were almost certain to have gears. With the return of heavier models, gears are again becoming useful. This year’s crop of contest ships is sure to include many geared models. In the past, models with airfoil fuse- lages proved to be unstable unless care was taken in picking the wing section for the fuselage. The section must have a stable center of pressure location. That is, the forces of lift and drag must always act through the same point re- gardless of the angle of incidence of the wing section. The Munk airfoil, Num- ber 6, is such a section. The center of pressure location does not vary any appreciable distance in a range of angles from O to 20 degrees. NEXT MONTH, we'll tackle a model of the Crusader, a new high-speed twin-engined ship. The Crusader is a new design. _A tear-drop body is at the center of the wing. The two motors are located in the leading edge of the wing. The tail is mounted on two booms extending from the wing. The high speed is 233 m.p.h. Watch for this dandy flying model. A (C©) Ghook CO