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The construction of model aeroplanes is essentially simple and for those wishing to experiment it is an ideal method of gaining practical knowledge of the new science of aeronautics.

Aside from the utilitarian standpoint, there is another aspect hardly second or less important. A well balanced little machine which will leave the hand and soar away under its own power is a source of fascination and delight not only to its maker, but to the spectators of the flight as well.

This little volume has been planned to present the material it contains in such a manner that it will aid the judgment of the experimenter and assist him in developing his own ideas. To make it of immediate value to the novice a number of detailed plans for building various machines have been included. For the greater part these machines have been designed rather to fly greater distances than to appear like some man carrying prototype.

PLATE I. Launching a Model Aeroplane.

 INTRODUCTION.

 CHAPTER I. GENERAL PRINCIPLES UNDERLYING AEROPLANE FLIGHT.

 CHAPTER II. GENERAL REMARKS REGARDING MODEL AEROPLANE CONSTRUCTION. THE QUESTION OF RESISTANCE. WEIGHT. STABILITY.

 CHAPTER III. PLANES AND RUDDERS. ELEVATORS AND TAILS.

 CHAPTER IV. THE FUSELLAGE OR FRAMEWORK.

 CHAPTER V. MOTIVE POWER.

 CHAPTER VI. SCREW PROPELLERS.

 CHAPTER VII. BEARINGS, THRUST BLOCKS AND GEARS.

 CHAPTER VIII. BUILDING AND FLYING MODEL AEROPLANES. The Blerioplane Flyer. (Plate II.) The Monoplane Flyer. (Plate III.) The Baby Racer. (Plate IV.) The Peerless Racer. (Plate V.) The Competition Flyer. (Plates VI and VII.) The Long Distance Racer. (Plates VIII and IX.) Fleming-Williams Flyer. (Plate X.) FLYING THE MODELS.

 PLATE I. Launching a Model Aeroplane.

 FIG. 1. Diagram showing a kite held in the air by the action of a wind. The dotted lines and arrow heads represent the direction and force of the wind.

 FIG. 2. Diagram representing a typical monoplane. The only remaining requisition is that the aeroplane may be guided at will, caused to rise or fall or be steered to the right and left. The devices used to accomplish this are two rudders called respectively the "elevator" and the "steering rudder." The "elevator" takes the form of a small surface carried either in front or behind the main supporting surfaces and enables the machine to take an upward, a horizontal or downward course accordingly as it is adjusted. It acts as a rudder to steer the aeroplane up or down or to hold it to its course in exactly the same manner that a ship's rudder steers it to the right or left. When it is desired to direct the aeroplane upwards, the front edge of the elevator is raised so as to set it at a greater angle with the horizontal. If the aeroplane's course is required to be downward, the front edge of the elevator is lowered.

 FIG 3. Diagram showing the makeup of a biplane (Wright).

 FIG. 4. Two methods of controlling the lateral stability of an aeroplane.

 FIG. 5. The disturbance created in the air by a square object. The arrow points in the direction of motion. The space in the rear of the object is the scene of violent eddy.

 FIG. 6. The disturbance caused by a triangular body moving through the atmosphere.

 Plate II.

 FIG. 7. Showing the disturbance created by a small spar on the back of a plane.

 FIG. 8. Diagram illustrating the ichthyoid shape and how smoothly it slips through the air without creating an eddy.

 FIG. 9. Of the three shapes shown above, the round one will slip through the air with the least disturbance and resistance. A bar of wood like (A), 2 inches square, showed a "drift" of 5.16 lbs. when placed in a breeze blowing 49 miles per hour. Turning it as shown by (B) changed the "drift" to 5.47 lbs. A round bar, 2 inches in diameter, like (C) showed 2.97 lbs. "drift" under the same conditions.

 FIG. 10. The figures given above each shape show the "drift" in lbs. of wooden bars of those shapes when placed in a wind blowing 40 miles an hour. The bars experimented with had a depth of 9 inches in the direction of the arrows and were 2 inches wide.

 FIG. 11. Flat and dihedral planes.

 FIG. 12. The action of the air upon a curved and a flat plane. We have seen that by the effects of the resistance of the air, an aeroplane may be sustained in the atmosphere. We must now see in what manner we can use these effects to the greatest advantage.

 FIG. 13. Section of a built-up plane showing how a rib is made. When made small, they offer greater "drift" or head resistance than a single curved surface plane and cannot because of the delicate structure necessary to make them light, withstand hard knocks. They have the further disadvantage of being from a constructional standpoint very hard to make smooth and rigid.

 PLATE III.

 FIG. 14. How ribs may be joined to the long members.

 FIG. 15. Form for bending the planes.

 FIG. 16. A good method of building a wooden plane.

 FIG. 17. Various shapes a plane may take.

 FIG. 18. An edgewise view of several planes showing the different ways they may be bent to secure stability.

 FIG. 19. The various ways two planes may be combined to secure stability or form a biplane.

 FIG. 20. Fins.

 FIG. 21. A simple "motor base" or fusellage.

 FIG. 22. Paper Tube Fusellage. Part of the tube is cutaway to show the rubber skein inside.

 FIG. 23. Two methods of gearing a propeller.

 FIG. 24.

 FIG. 25.

 FIG. 26. Method of laying out a screw propeller, that is, determining the angle of the blades at different points.

 FIG. 27. A propeller of the truly helical type delivers a cylinder of air in which all parts move at the same speed as at A. A propeller having blades of the same angle throughout their length throws the air as in B in which the centre of the cylinder moves more slowly than the outside.

 FIG. 28. Templets for testing and carving a propeller.

 FIG. 29. A simple method of forming a propeller from sheet metal.

 FIG. 30. A built-up metal propeller made of aluminum.

 FIG. 31. Metal Propeller.

 FIG. 32. Method of carving a propeller of the truly helical type.

 FIG. 33. Methods of fastening propellers to shaft.

 FIG. 34. Method of forming sockets for joining struts, etc., by cutting from sheet metal.

 FIG. 35. Bent wood propellers and the methods of fastening them to the shaft.

 FIG. 36. Propeller blank (top). Carved propeller (bottom).

 FIG. 37. Langley type propeller (top). Wright type propeller (bottom).

 FIG. 38. Quasi-helical propeller.

 FIG. 39. Blanks for racing (top) and chauviere (bottom) propellers.

 FIG. 40. The first step in carving a propeller. The blank. Hollowing the first blade.

 FIG. 41. One blade hollowed. Hollowing the second blade.

 FIG. 42 Rounding the back of the first blade. Rounding the back of the second blade.

 FIG. 43. All carving finished. Sandpapering to secure a smooth surface.

 FIG. 44. Varnishing. The propeller finished.

 FIG. 45. Accentricity. The effect of placing the center of gravity too low.

 FIG. 46. Simplest method of fitting two propellers to a model aeroplane.

 FIG. 47. A method of arranging two propellers on the same axis.

 FIG. 48. Simple bearings.

 FIG. 49. Double bearings.

 FIG. 50. Simple thrust bearing.

 FIG. 51. Ball thrust bearing.

 FIG. 52. Hooks.

 Plate IV.

 Plate V.

 Plate VI.

 FIG. 53. Method of holding plane to frame with rubber bands.

 Plate VII.

 FIG. 54. The Peerless Racer.

 Plate VIII.

 Plate IX.

 Plate X.

 FIG. 55. Racing blank and propeller.

 Plate XI. Winding a model.

 FIG. 56. A winder made from an egg beater.