Aerobatic Model airplane

On modern controlline acrobatic model athlete spends an enormous amount of time, energy and resources. For the next sports season, as a rule, he has time to prepare only one piloting the model, then quickly trying to learn all of its advantages and disadvantages of the flight during the first workout. When you change the fundamental design of the model will inevitably have long and carefully adjust and regulate the aerobatic qualities of the new machine under your individual driving style, which sometimes goes on half of the season.
It is quite understandable fear of a new car smash causes athlete's "slow down." Sometimes on the development of new technology takes unacceptably long time. And the sport is a very important factor. If for some reason you can not quickly and safely pass through the stage of development, the season "disappears." The result - athletic performance (and therefore fall sports rating). Or athlete to temporarily skip transcripts competition (which also leads to lower ratings and the emergence of talk about instability athlete).
Therefore, those who are seriously interested in Cordoba aerobatic models, periodically appear about the need to have in addition to the main "fighting chempionatnoy" machine dedicated model for seasonal training (which may be a potential substitute for the contingency). It is this technology and is dedicated to today's publication.
Pilotazhka offered to your attention is a welcome compromise that satisfies the requirements of high-flying characteristics with a very high technology and overall simplicity of design. This model was created based on the experience of leading Czech and Russian athletes. Application of particularly scarce materials and sophisticated technology it has been avoided.Cord wing aerobatic model aircraft
Wing of constant thickness and major chord (no flap). Main circuit classic - with sewn nose Quezon type. All ribs are processed in one batch. Then pack disassembled and each rib sequentially numbered and easier. This is followed by the assembly on the longitudinal members, insert the leading edge and the wall between the frame rails. The wall is made of balsa plates with vertical fibers. The four sections of root wall thickness of 3 mm, the rest of the console 2 mm.
In the central section of the wall of the spar is made of 4 mm birch plywood. This wall bonded epoxy adhesive on two plywood plates on which is mounted unit ready rocking. Completes the assembly of the frame assembly at the rear edge of the immature form of the profile (balsa rail section 14 x 10 mm). Then you can start sewing the nose wing plates balsa. At this stage, it is strongly advised to frequently monitor the absence of twist frame, and if they occur in a timely manner to correct the wing. Otherwise, after sewing the forehead remove distortions will be impossible!
It should be dry well assembled frame, before embarking on a sticker on the shelves lining the ribs and panels of center. In the application of PVA glue type to survive the wing at least 12 hours in a constant temperature of about +20 °. On the dry skeleton doprofiliruyutsya front and rear edges. In general, when the assembly is mainly used PVA glue type "building" grades, as it tougher than the office, do not turn yellow in the joints. It is important not to dilute it with water, and ethyl alcohol (about 30%) of the initial state. The obvious advantages of this - to prevent decay adhesive during storage, fast drying, very low warpage and sharply reduced the swelling of wood glue in the nodes.
Wing tips cut from the packing foam and covered with two layers of fiberglass 0.1 mm thick epoxy resin. However, it appears that it is easier to manufacture of wood and doodle on it molded fiberglass ending. By the way - in practice and in transit often suffers from nicks and external ending to replace it easier to have on hand ready prepared food, than venturing processing of foam. In addition, the internal ending, made in the form of a hollow shell strong enough, if you want to allow elementary simply make her adjustable output node ropes control.
Do not forget the outer wing section seal at a weight of 30-40 grams. Covering - Mylar film thickness less than 25 microns. Leather-clad wing is delayed until the beginning of the joint assembly to the fuselage. Flaps vystrugany from solid balsa plate thickness of 10 mm. Their root ends reinforced plates of millimeter plywood. After processing, the holes for the hinges and hinge bracket of the drive, they are primed with liquid nitro lacquer in one layer and pasted color thermofilm Solarfilm type or equivalent in properties. The flaps are mounted on conventional purchased plastic hinges (three hinges on each flap) after the end of the assembly and finishing of the entire model.Stabilizer and elevator cord aerobatic model aircraft
Stabilizer and elevator tselnobalzovye, inlaid design. Characteristic shoulder in the profile horizontal tail explains the appearance of a very interesting and useful aerodynamic effect. For small deviations of the elevator (up to 7'-10 °), to properly shaped plumage appears peculiar dead zone. Now do not need to be perfect precision return handlebars to neutral after a sharp maneuver, as the "zero" zone greatly expanded.
On the effect of thickening the trailing edge of the stabilizer close to that employed at one time to another reception, also facilitates the piloting model (I mean deliberately pledged to the control of significant backlash, reaching on the handlebars and the flaps 6 °). Effect due to the presence of the step between the stabilizer and elevator performs well not only in the derivation of the model of the maneuver, but when you type in the straight sections of the square and triangular shapes. However, there is one negative aspect of this plumage. Accustomed to managing such a model, then it will be very difficult to move on to normal.
If you are a supporter of conventional profiling horizontal tail, so please move away from the proposed scheme, and thicken the elevators to the thickness of the stabilizer. Keep in mind that the figures suggested the option that the design logic of the author and sports (but different from the views of many Russian and foreign athletes). Note the stabilizer spar, made in an assembly of pine shelves and balsa wall.
Replace the node tselnobalzovym unacceptable - this version has been tested on the previous model, and showed a lack of strength of balsa to collapse resulting from loads. In the version in the root of the spar arose buckling wood (the defect was noticed by swelling stitched at the root of the stabilizer). Sheathing horizontal tail - Mylar about 25 microns thick. Hinged elevator as well as flaps - three loops at the console. For finishing the wing and tail, the multicolored pieces of film type Solarfilm.Fuselage cord cord aerobatic model aircraft
The fuselage of the rapid form of wooden construction. The basis for the installation of the board are carved out of balsa plates. We recommend using balsa with a density less than 0.12 g/cm3. Stick to the sides on the inside lining of the reinforcing mm plywood, which begin in the engine bulkhead and ends near the trailing edge of the wing. At this point, you can mark and rough saw out the window under the wing.
Since the edge of the airfoil contour very close to the top edge of the board, in this place connected technological balsa wedges, which, after installation of the wing will need to be cut. The axis of the wing is below the axis of the engine to 5 mm, and the axis of the horizontal tail is above the axis of the motor by 10 mm. On the starboard side in the bow cut a hole under the fuel tank.
The length of this niche may be equal to the distance between the frames, allowing the tank to move along the axis of the model for the fine adjustment of the operating mode of the engine of evolution. To be successful in advance to collect in a single structural unit with two power motor-frames (No. 2, 4 and 6), and mount the "thorn in the" details of the main landing gear bearings (key 29 and 25). Strictly control the size and axial arrangement of parts, as this will depend on the accuracy of all further work on the body of the model.
Assembling the best run on epoxy resin. While the glue is cured, it should mark the exact location of the tail of the composing frames and stick them on the side of the vertical slats. For proper assembly of parts with flanges, drawing on the stocks fixed fuselage "top view". From the outside contour of the fuselage pins pinned two rail section 6x6 mm. They form a pattern that will help prevent axial deformity. Now set the vertical side panels inside the template, just Coordinate them with each other and stick on the ground pins.
Proceed to the formation of the tail frames, pasting their rails, from the tail. Glue the bow then ready node. Assemble the tail landing gear and Glue it in place. At this stage, you can mount the fuselage and stabilizer (do not forget to install the bracket that connects the console of the elevator with a welded pig). Then glued to the bottom of the nose to the landing gear. The resulting "semi-finished" fuselage unstock. Glue the wing. Fabricate and fully assemble the fuselage control system. Traction of the flap to the elevator vystrugana balsa, its shanks are made of pieces of steel spokes with a diameter of 2 mm.
Now you can sew up the bottom end and get back to making gargrota and vertical tail. Fairing is made of U-shaped plate-stick or hollowed out of a single V-bar balsa. The upper part of the compartment above the wing plate sutured balsa, and her mount additional shaping frames. Molded and bonded front gargrot. The resulting body of the model can be podshpaklevat, proshkurit and primed to finish.
Nose cone engine compartment is formed by attaching tailored by location balsa sticks and plates, followed vyshkurivaniem received blank on the form. Another option - vykleit hood of fiberglass or plaster on a wooden disc. Canopy can be transparent, tinted or colored (opaque). It is mounted on the model only after the completion of its decoration.Strut cord aerobatic model aircraft
Landing gear is a spring plate of D16T thickness of 2.5 or 3 mm. It is attached to the fuselage support two screws M6. Wheels - by "thermals", 040 mm. Vykleeny fiberglass fairings. Even during the design pilotazhki be erected on it Savelovsky motor MDS-40, and the first time the model was fitted to them. But the case is allowed to buy from friends engine Thunder Tiger 46. Installed homemade diffuser 06.5 mm instead of the broken radiokarbyuratora and testing the engine on the model, it became clear that it was "down" better MDS. The result very much.
The engine runs smoothly and steadily with a homemade wooden propeller 300 x 120 mm at any point of the hemisphere, to set nekaprizen. Despite its large displacement than the MDS-40 (7.4 versus 6.5 cm 3 cm 3) while the engine is barely decreased (a difference of no more than 12-15 seconds). Parameters as the propeller mounted on the MDS-40, are as follows: a calm day 290 x 140 mm, on a windy day 282 x 150 mm. Homemade diffuser for MDS has orifice diameter of 6.1 mm. The recommended location of the center of gravity of the model is 80 mm from the front edge of the wing - almost on the side member. Recommended flap angles ± 18 ... 20 ° from the neutral position, the elevator - ± 27 ... 30 ° from neutral.
(Author: P. Nesterov. Source magazine models sports and hobbies)

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