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Only laudatory conclusions on flight characteristics received from everyone who was able to make her acquaintance, new polupoltina RC car. A great combination of handling and stability in all axes, a surprisingly low – speed flight, small sensitivity to sudden gusts of wind and good properties in the plan after stopping the engine and landing — here is the list of its advantages. The model is so poised in the air, despite diskoplana scheme, it can be recommended even for beginners in radiopilot to purchase both initial and follow-up skills in management. The latter makes this cruise a very versatile machine, especially considering its just amazing strength.

Successful development of “polyphyletic”, based solely on readily available domestic materials, and reproducible in any non-specialized conditions, and has an interesting history. The FACT THAT the basis for it was more than a famous “historical” model, first developed in America in the sixties and received after the release of the very popular packages-set the name to Square Shooter. Of course, original car meet, far from modern. However, it in ten years was inspired by Czech athletes at creating a more modern modifications, calculated no less to participate in the competition class RC M2. Our modelers this class a little familiar, so we mention that, in accordance with its requirements polyprotein model should not have ailerons. After reconstruction Square Shooter received a tricycle landing gear and, most importantly, new-fangled profiled wing (applied profile type E-474), largely contributing, along with proper design of the device successful development. Modified Square Shooter subsequently was based on published drawings in a variety of instances; almost all of them have fully lived up to their hopes athletes. Suffice it to say that in five competitions, including the M2 class, with models of this type in 1971, five times the line was busy the first place and once second.

 

Czech modification from a technological point of view is so simple that its construction modeller “mediocre” to cope over 15-20 evenings (of course, if you have already cut and polished sheets of balsa). Sure that this design will also attract our athletes (especially now that the balsa again becomes more available), so at least talk a little about its features.

 

The fuselage has a sidewall balsa 3 mm thick, reinforced at the binding area of the wing inner covers out of plywood with a thickness of 2 mm. Assembly of the fuselage is upside down on the plane of the upper generatrix. Only three of the existing bulkhead cut from the same plywood and glued into the front fuselage. The upper and lower fuselage is also balsa with thickness of 3 mm. Stringers and spars, the fuselage does not have. He still is extremely durable and tough with little weight. The only condition is the exact fitting of parts and use of quality adhesives for Assembly.

The tail is fully carved from baltovich plates 4 mm thick. the Front edge of the stabilizer is reinforced of pine lath cross-section of 4×4 mm and tips — balsa plates glued across the layers of the main part. The width of these plates is about 15 mm at a thickness of 4 mm. As a stabilizer, and fin are mounted in the fuselage in the prepared slits.

 

The wing, providing rigidity to twisting of the caisson has a spar made of balsa plate with a thickness of 5 mm, double-sided paneling of the forehead balsa 2 mm thick and double (team) the front edge of baltovich plates of thickness 3 and 7 mm. the Latter is attached only after the skin of the forehead with balsa that technologically simplifies the manufacture of the wing. Ribs carved from balsa wood with a thickness of 2 mm; the Central thickness is 10 mm. the trailing edge is formed by two plates of balsa wood with a thickness of 2 mm. Of the same material carried and shelves of ribs a width of about 8 mm. To the fuselage the wing is attached at the classic today option — beech pin and glued to the front edge and the Central rib and within a plywood frame and a nylon screw MB in the zone of the trailing edge.

 

 

 

Fig. 1. The underlying model. Designed to fit glow motor a working volume of up to 3.5 cm3. The drawings and the description of the model prepared on the basis of the publication in the Czech magazine “Modelarz”.

 

 

Fig. 2. Wing profile base model.

Due to the high requirements for precision aging of the contour profile polulineinogo type pattern is reproduced in natural size. The main positive quality of the profile type E-474 is a minimum tendency to breakdown at high angles of attack, and good bearing properties in a wide range of flight regimes.

 

 

Fig.4. Domestic enhanced modification of the basic model, is designed for the mounting surface of the motor working volume up to 7 cm3. Under these received values of takeoff weight and specific load bearing surface provides the possibility of operating the motor in the soft “four-stroke” mode with appropriate selection of the propeller.

 

 

 

R and S. 4. The design of the fuselage.

 

 

R n p. 5. The design of the wing.

 

 

Fig. 6. Design of the horizontal tail.

 

 

Fig. 7. Aerobatic fuel tank.

 

 

Fig. 8. Chassis pilot skis-fairing.

 

In the present model was mounted glow motor a working volume of 3.14 cm3 in Japan, and obviously not modern forced type. With him the model confidently executed all of the figures required in the class M2. The authors also recommend any version of the engine working volume of 3.5 cm3 and also allow you to use powerful engines of 2.5 cm3. In the original version, the model is equipped with a plastic fuel tank with a volume of 100 cm3, which is enough for 11 — 13 minutes of flight.

 

Chassis tricycle. The front Desk is curved from high quality steel wire 4 mm in diameter and rigidly fixed to the engine frame. Main landing gear from piano wire with a diameter of 3 mm are mounted by a known technology in beech wing bars.

 

Czech Square Shooter was controlled with a proportional equipment “Varioprop”. Involved handlebars height and rotation, and the control system of the gas engine. The authors confidently allow even the use of discrete devices (with limitation of turn of the rudders). The original form with proportional control of the elevators should deflect up and down by 15°, and direction — to both sides at 30°.

 

Balancing is directly related pereprofilirovanie wing. When using proportional control equipment degradation angle (installation angle of the wing relative to the stabilizer) is set equal to zero. For beginners or holders of the “discrete” the recommended angle degradation is taken as equal to 0,5—1°. The engine being cut down by 4-5 degrees down and 2-3 degrees right. It is noted that excellent performance characteristics are provided when the mass of the model not more than 1,600 g. the Upper possible limit it is possible to recognize the value of 2000 g, although such weighting is not desirable.

 

 

The fuselage of the new model designed according to not seen another scheme. The power part is formed by two, upper and lower, spaced along the height of the strong belts, rigidly connected front and tail of the fuselage. The upper belt is formed of a doddle “Board” — plate made of pine with a thickness of 5 mm (here and further in all the places that use this wood, it can be successfully replaced by a thick lime-tree; but the best results still gives the use of light, the so-called music, eating with fine layers and a specific gravity of about 0.4 — 0.45 g/cm3; the whole Assembly is conducted only on plasticized epoxy resin K-153). Shown glued to her bottom slats to the stringers — does not enhance the belt, but only elements that can improve a bunch of belts samotnie elements, and that really quite minor, to effectively make a recess simulating the cavity of the cabin. Front pair of stringers has a section 4×8 mm each, and rear — 4 x 5 mm.

The lower zone begins ahead of a powerful birch boards motor section 12×15 mm, turning then through the diagonal joining two pine under-wing rail cross-section 6×13 mm and further in the rear in a couple of stringers 6×6 mm each. Two front bulkhead is made of plywood thickness of 5 mm, and all the rest — from polished furniture or construction plywood thickness: 3 mm Power covering the forward fuselage is made from aircraft a half-millimeter plywood, and is forced into it flush with the fuselage, gently moving in a zone by using the extended sanding on a mustache and a corresponding adjustment is located underneath the power rails. In the zone of passage of the pins through the wing of the second last frame is enhanced by additional invoice plywood front, top, over it is cut a window for the backup option of placing the power supply equipment. When preteenie tail part that can be useful. The rest of the forward fuselage is made arbitrarily. Here it is only important to reliably separate the cavity of the motor is glued to the bottom of the beams motor plywood wall. The tail pop is closed embedded flush plywood sheathing (thickness of plywood is 1 mm, the layers of shirt vertical), vertical elements of the keel and the bulkhead in the area of the front edge of the stabilizer. The entire tail section from the bottom of the wing is sheathed with millimeter plywood. The same material is laid out lo-gementa the surface under the wing. Area shown on riannah points, is filled with the foam plates with a thickness of 5 mm on the right and the left. During Assembly of the fuselage it is important to provide a sequence of operations, which will stick securely soldered tin fuel tank tightly. The headrest and the lantern is made arbitrarily. The dorsal fin — lime plate, thickness: 3 mm — simultaneously performs the functions of reinforcement of the upper power zone. Before finalizing the design of the bow into the bottom of the beams motor with pre-impregnated chopped screw holes on the resin steel screws M4 for engine mounts. In the plywood sheathing of the sides of the tail is cut longitudinal of the window to exit the control rods. As in the whole fuselage is more than powerful and tough, soft lining carries only a decorative function and can be made of any lightweight film. Under the rear edge of the wing to the frame privertyvaetsja dural biscuit with M6 thread screw mount carrier plaskolite on the fuselage. Weight ready parts chno akrilovogo of the fuselage in the proposed execution together with feathers not more than 400 g.

 

Two wings, like the fuselage, also characterized by non-traditional power scheme. The front edge is formed by the pine monoporosa a cross section of 12 × 20 mm, tongshui on the edge of the wing to 10 x 16 mm. the Terminal parts of the wing are closed by reinforced ribs of lime with a thickness of 8-10 mm (lightweight), sheathed with the outer sides millimeter plywood. All scarves are not docked to the ribs, and drawn through the slits in their noses and shanks. Flaps-ailerons pine, cross-section 5 x 30…35 mm. They have a wedge-shaped profile gives the thickness of the trailing edge at least 2 mm.

 

Very unusual on this model posted and apparatus. Almost all of it is mounted in the Central zone of the wing, which due to its powerful design better protects expensive nodes in extreme situations than the fuselage. On the created model instance between the cellular Central ribs glued the frames, and the edges of the auxiliary lugs that enable them to bind to the frame top and bottom covering from millimeter plywood with a transverse direction of the fibers of the shirt. Before applying panels indicated on the drawings cavity spread foam stamps PHV. The skins are made for only one window compartment above the servos. Through a first forward inserted power supply unit (preceded by a protective pad of dense foam rubber), then back — wrapped in a thin foam rubber to the receiver, and then, finally, comes the unit servos on a single dural curly Board. The latter relies on not shown in the figures of the boss — their shape and position depend on the specific size of the nodes of the instrument. The ailerons are driven by a pair of brackets, wire, OBC 0 to 3 mm, carried out using thin-walled brass tube. Mm plywood sheathing of the Central zone of the wing extended back to converge together and form a semblance of a fairing. Wing ready to sand and is covered on the glue “Moment” or N-88 Mylar film with a minimum thickness of 0,04 mm. After stretching of the film and editing formed the unique strength and hardness in a twist design with a total weight of about 400 g In the appropriate places on the front edge are glued beech pins for fixing of the wing to the fuselage, and the rear edge of the drilled hole for the screw MB. When cording polyester please note that at the joints the film should molestias each other by not less than 15 mm To the trailing edge it proclaimed.I’m only at the rear end. A finishing operation, painting and installation of special polutropos under the rack chassis in the corners between the power edge and beech insert. The holes for the screws clamping plates drilling only in beech.

 

The elements of horizontal and vertical models are identical in schematic and design. Edges and endings, and insert made of light pine plates with a thickness of 5 mm. Finished Reiki embedded “dovetail” into the front edge, and rear diamond-shaped, having a preliminary cross section of 7×7 mm, connected by scarves. For reliability, the joints are flat with edges winglets also cut.

 

Note that elevators and directions it is best to make only after complete Assembly and balancing of the model. Due to material selection and construction of these parts will be the easiest way to achieve the desired alignment.

 

Tightly seal the fuel tank in connection with its subsequent unavailability must be soldered from tinned sheet thickness 0.3 mm more than reliable. As Ploiesti flight tracking system kit fuel through into the front wall of the tank a large brass tube, clearly seen in the drawings. This technique allows not only to reliably seal this part of the tank in the hole near the frame and thus prevent the entry of fuel mixture into the cavity of the fuselage, but if necessary it is easy to control and replace the tracking system.

 

Landing gear are bent from wire, allied with a diameter of 4 mm. As already mentioned, the strut (removable) invested in glued into the wing Logement polutrusy and pressed steel plates with screws. At the ends of the struts or conventional model wheel with a diameter of about 60…70 mm, or a kind of ski-altenately. For the latter you will need to make your own pair of racks, but it makes sense — these skis during takeoff and landing on the grass behave better than conventional wheels, and easier latest.

 

Weight of the model approximately as follows: the fuselage Assembly 400 g, the wing is the same chassis with ski-fairings — 100 g, onboard part of the control equipment up to 400 g, the motor set — 300 grams (“rainbow-7” wooden propeller, lightweight spinner, muffler, and radiolaboratory). Total — 1600 as a result of calculations we get the amazing value of the specific load on the bearing surface 34 g/dm2 in the amount of 41.5 g/dm2 wing. In addition to low specific load is very low and the engine load that allows you not only to fly in an unusually low speed, but also to have considerable excess thrust at all flight modes. For brought ambulancewoman “Rainbow 7” with a lightweight piston, as and for MDS-6,5, we can recommend a wooden propeller with a diameter of about 270 mm and a pitch of the order of 130 — 150 mm.

 

Talk about a good design, you can finish your sentence: try to make the next step in prereconstruction this machine. Perhaps it will relate to the equipment (by the way, on the proposed modification of the wing includes a wheel-the cars-drive ailerons and rudder), or the schema and layout of the chassis. But overall this stuff. Now talking about larger changes. These include, for example, attempts widespread use balsa instead of pine while preserving the power circuit model. The theory says with the same original design strength balsa nodes this scheme can be two times lighter than pine. The thickness of, for example, the upper zone of the fuselage reach 10 mm, and the cross-section of the power monocracy wing 18 x 30 mm (not to mention the plywood parts, the thickness of which after the transition to the balsa can be increased three to four times). Rate not only the possibility of further simplification of the model, but also corresponding sharp decrease in the expense of this expensive wood.

 

V. TIKHOMIROV, master of sports