The English aviators who excel in constructing very light models have had great success with what are termed "one ouncers." Some of the models of this type weigh even less than one ounce. The distance qualities of these machines are marvelous. Mr. Burge Webb claims a record of 1,500 feet in a straight-away flight by one of his one-ounce models. Can I make a model fly by turning the propellers in the same direction? It is doubtful. In using twin propellers the blades should, of course, revolve in opposite directions although they are wound up by turning them away from the center. Be careful, of course, to mount the right and left propeller in the proper position. Some aviators believe that the propellers should be turned at the same time,—there are machines to do this,—in order that the thrust may be exactly balanced. What is the longest flight ever made by a model aeroplane? Mr. Flemming Williams, the English expert, claims to have made a flight of almost exactly one-half a mile. His machine, which is illustrated in this volume, weighs ten ounces. It was launched by throwing it in the air, and in making this record flight travelled with the wind. What is the best weight for a model? Here is a very difficult question. It depends entirely upon what you are trying to accomplish. In England, where everything is sacrificed to the distance qualities of the model aeroplane, the best models vary from five to ten ounces in weight. In America, where much more is required of a model aeroplane, since it must rise from the ground under its own power and possess considerable automatic stability, the average weight is much more. What is the average speed of a model aeroplane in flight? About twelve miles an hour. When sailing with the wind this speed may be increased indefinitely. In sailing against the wind, a model aeroplane may creep along while remaining almost stationary. Will tandem propellers make my model swifter or steadier? Little has been accomplished either in America or in England with the tandem propeller. Several small French models have been flown in this way, but without striking results. Theoretically, the torque of the propellers balance one another in this position; the forward propeller creates a considerable backwash, and the second propeller works at a disadvantage. Further experiments may discover an advantage in this arrangement How hard should I throw my machine when starting it? It is not a good plan to launch the machine at a higher speed than that at which it travels under its own power. By increasing its speed, you are likely to set up violent oscillation, and, as explained elsewhere, a model becomes unstable with increased speed. It is better to start it too slowly than too rapidly. In the case of a glider, of course, it is well to throw it with all your might. This is a problem, incidentally, which does not occur when the models rise by their own power.