SAVE THE ROTOR | MODEL CONSTRUCTION

For many years the rules of competition flying-th activities of the International Federation of air sports is a category microrocket with authorityrules descent. At the time, the athletes were given this technique a lot of attention, then about her for some reason for a long time seemed to be forgotten. However, there is now a surge of new interest in rotochutes—so among modelers athletes call missiles with authorityrules descent.

Wanting to help the designers to keep up with resurgent directions, rich in possibilities of technical research and creativity, as well as answering letters from readers, the editors offer an interesting model of rotachute master of sport of the Tyumen region Vladimir Menshikov. Recognizing the sophistication of the model, it should be noted that still it is under development. So for all you followers of the flying sports, this scheme can serve not only as materials for copying, but as a starting point to create even more sophisticated designs.

We offer to your attention the model of the class bear is made by traditional technology and a little different from equipment championship classes, BSA and BBA. Structurally it can be divided into three parts: the rotor, the motor unit and fairing.

The rotor is made in the following way. On the mandrel 30 0 mm molded fiberglass cylinder with a length of 190 mm. torched on both edges and is cut lengthwise into three equal pieces. Thus obtained segments-fold. To each of them on the inside for rigidity stick two frame structural element, and the bottom mounted, Bal-pink “crackers”. The latter serve as a kind of adapter inserted in the cage propulsion unit in preparing the model to run. At their lower ends are mounted sectors balsa, forming together a circular frame. It protects segments-fold (rotor blades) from burnout during actuation of the lifting charge mrad.

At the top of each sash is attached from the inside of the arm from the Linden slats section 3,5×4 mm. Lateral to the plane of the levers projecting beyond the edge of the blade, are reinforced with plates made of sheet celluloid, then in these zones of drilled holes 0 1 mm. Adaptivepath the ends of the levers for the attachment of rubber thread return.

Fairing ogive shape is molded from fiberglass and has two bulkheads. First, thickness of 2.5 mm and 10 mm hole 0 in the centre, installed at a depth of 47 mm from the lower edge and serves to attach a rubber string return. The second frame is located 6 mm from the edge of the fairing and is a member of the three arms of the levers folds the blades. Axis swivels are made from strips of steel wire 0 1 mm. To the free movement of the levers in the head fairing on the perimeter of its lower edge cut three rectangular groove 5,5×6 mm.

Motor block total length of 90 mm is also molded from fiberglass and consists of two pre-manufactured parts. The first cylindrical tube 0 13 mm, the second ferrule streamlined shape. After Assembly of these parts on top to a depth of 1 mm is inserted into the balsa frame and glued in place.

Rotocut has three stabilizer are made from balsa plates of 0.5 mm thickness and reinforced with thin fiberglass. They are mounted on the cylindrical part of the propulsion unit butt joint using epoxy. Outside along one of the stabilizers is thread suspension.

Model rocket rotachute class Ѕ9А:

1 —fairing, 2 — rubber thread disclosure (return) of the blades-wings, 3 — frame, 4 — fold-blade, 5 — tube propulsion unit, 6 — blade stabilizer, 7 — arm leaf-blades. 8 — pad lever. 9 — the frame folds, and 10 “cracker”, 11 — cage motor unit, 12— frame motor block, 13 — thread suspension of parts of the model 14 — a bracket of fastening of the lever of the fold, 15 — sector.

Weight of model without motor is equal to approximately 7.5 g.

Preparing the model to run

Near one of the ends of rubber thread with a length of about 50 mm and 0 1 mm to tie the knot. The free end of the conducting hole in the frame of the head fairing. Moving the thread to the outside, stretch it through the hole in the suspension arm leaf-blades and fasten, tying the same knot. This is done with all the doors-blades, achieving the tension of the rubber threads of the same angle deviation. If the model is prepared to launch the blades are turning downward, forming a folded cylindrical body of the rocket. The lower part of the doors, thanks mounted on them “crackers”, form a Bush which is tight enough to enter the cage of the propulsion unit. Before this operation the thread suspension neatly tucked inside the model. Mounted engine brands MRD-2,5-3-3.

After 3 — 4 s after the main charge of the engine undermined by the lifting charge and the upper part of the body goes up. Fold open, turning into a blade of the main rotor, and the model switches to the mode authorityrules descent. The length of the thread of the suspension is selected in a practical way.

V. ROZHKOV

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