RETURN TO BOOMERANG

THE RETURN OF THE BOOMERANGToday the state of technical creativity of pupils, I think we all know — it is deplorable. And even a talented teacher to inspire children is becoming increasingly difficult. One of the reasons the sharp deterioration of the material base of non-school institutions that lead to exclusion from group work sites that require long time to manufacture. It is possible to offer teachers some technical circles (primarily — aircraft modeling) to include in the plan of work of the first year of lessons build exotic aerodynamic projectile like a boomerang. Experience shows that it is quite affordable for newbies. Requires wood and simple tools: a plane, a knife, a rasp and sandpaper. Production time is two or three classes.

At the time, in the pages of “Modeller-designer” (No. 5 of 1993) described the construction of the classic boomerangs. However, for groups of more than l appropriate three – and four-bladed.
 
Like boomerangs in the championship of Russia for flying sports and the city of eagle has demonstrated Morozov, lecturer at regional station of young technicians. For many years he enjoys making boomerangs and has a large Arsenal of these kind of sports equipment.
 
Offering two simple designs, developed by I. Morozov. Hope they will be of interest not only to heads of circles, but fans of flying models.
Four-bladed boomerang. To make it simple. The cross of two wooden plates — that’s the whole aircraft. All kinds of experiments with projectiles of this type have shown their amazing ability to fly. The most undemanding turned out to be a boomerang with a diameter of 400 mm. is Short about its construction.
 
Will need two pine or aspen plate length 400 mm, width 35 mm and thickness 5 mm. the Most important work — giving the Plate the required profile. If the boomerang will run the right hand, the frontal portion vertically located blades should be in front, and its convex surface on the left. This boomerang makes a circular flight in a counterclockwise direction. If the boomerang is under the left arm, the convex surface of the blade should be on the right and turn he’s going to do clockwise.
 
Four-bladed boomerang
 
Four-bladed boomerang.
 
Three-bladed boomerang
 
Three-bladed boomerang.
 
The boomerangs shown on the drawings, designed for the right hand. In the center of each plate drilled holes with a diameter of 3 to 4 mm, they are needed when gluing the plates and to balance the future of the boomerang. On each plate at a distance of 10-12 mm from the front edge of the hold with a pencil line, which serves as a reference point in the processing profile. The front part of each blade with a width of 10-12 mm should be cool, and back — sloping. In the end section of the blade will have a PLANO-convex profile.
 
Preliminary processing plate (profiled) doing with a knife and coarse sandpaper. The ends of the blades curve. After this operation, the glue plates overlapping so that between them was a right angle.
 
Final processing of the blades carry out tsiklej (will fit a piece of glass) and fine sandpaper. The outline of the profile is controlled visually or cut from a plywood template and bring the blade with it.
 
The final stage — colouring, varnishing and polishing the boomerang. Paint it in bright contrasting colors. The fact that this apparatus should be well visible in flight and after landing is visible in the bushes or thick grass.
After drying paint or varnish of the blade is treated with a small skin with water and re-cover with varnish. Then again grind. The mass of the finished boomerang — about 50 g.
 
Launch the boomerang, usually on the open ground, observing safety precautions. The fans can be behind the trigger. Take boomerang blade, and, slightly inclining to the right (20 — 30°), forward throw, giving it a rotary motion. Launching must stand face to the wind. The angle of the direction of the throw relative to the oncoming wind must be 35 – 40°.
 
Three-bladed boomerang. For its production will need three wooden plates with a length of 220 mm, a width of 38 mm and a thickness of 4.5 mm. Material — pine, Linden, aspen, birch. Birch is harder to handle, but the flying qualities of this boomerang above.
 
First on the smooth plane are glued three plates at an angle of 120°. After drying between the blades put three area-fairing with smooth transitions. Then each plate is treated, giving the blade PLANO-convex profile. “Trehlopastnye” is made the same as the four-bladed boomerang. The transitions of the profile of adjacent vanes also make a smooth.
 
Further balance sports equipment, pre-drilled a small hole in the center. Rotating “trehlopastnye” on a thin wire or needle, to determine the heavier blade, then lightly treated it with sandpaper. And so as long as the boomerang is not located in the position of indifferent equilibrium.
 
Finish carry out as described above.
 
Flight mass-shell, made of pine, is 55 g.

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