UNIVERSAL CLASS FЗВ | MODEL CONSTRUCTION

None of the types of modeling to the apparatus is not presented at the same time so many conflicting claims as to RC jumper gliders. Imagine that you need to design a machine that combines the properties of high-speed models, gliders-paritala and apparatus created specifically for ustanovlena of records range.

However, modelers safely solve such problems.

Long gone are the days when the competition marshalling of gliders could be seen only the usual RC priteli now hope to succeed with this model no. The modern representative of the class F3В — universal embodied experience of the creative search of many athletes. Its differences — speed and high aerodynamic efficiency, the ability to fly safely in strong wind and feel the weakest ascending thermal streams, gaining precious extra metres of altitude. The growing popularity of motocross class gliders is not only the widest possibilities of design search — there is another important factor. Gliders do not have the enormous overloads and vibrations as the motor model means, and the equipment can be used not so high-class and more available to the average athlete.

So, jumper RC glider-wagon. The number one issue for this kind of model — profile for the bearing surfaces. Recently, krossovki bolder refuse to use the well bearing profiles with strongly arched in the middle line. They came pretty thick, lenticular, which not only provides the high stiffness of the wings of the velocity model, but also excellent dynamic performance of the flight, its range. Modern means of towing (winch, petrol or electric) help to “highs” in the first of three exercises — for the duration of the flight — even in the absence of the ascending thermal streams. When performing other exercises that range and speed requirements to the supporting profile properties fade into the background. It is more important than minimal aerodynamic drag at angles of attack close to zero (more precisely, with insignificant coefficients of the lift force), which can not provide the supporting concave-convex profiles.

Most of the current models of class F3В have profiles calculated from known West German aerodynamicist Epplerom with the help of computing machines. The calculation was performed on the “model” Reynolds numbers, experiments in aerodynamic low-speed tubes showed high convergence of analytical and measured performance.

Modelers have great confidence in these profiles with the index E. the Only drawback (as, indeed, all such, laminarizing) — extremely high demands on the accuracy of the shape of the entire arch, until the tail knife-like part. However, modern technology is making wings with a completely rigid covering allows you to cope with this case. The use of such profiles on the finished glider with the consoles having at least partially the soft parts, is impractical.

RC model glider jumper:

1 — light, 2 — the nose of the fuselage, 3 — tow hook, 4 — tail boom of the fuselage, 5 — keel 6 — rudder, 7 — all-moving stabilizer, 8 — wing, 9 — Aileron.

The design of the wing:

1 — front edge (the tube D16T Ø 5X0,5), 2 — the covering (balsa S 1.8 mm), 3 — rib (balsa S 1.8 mm), 4 — fiberglass tube-pencil case 5 — shelf side rail, 6 — wall of the spar (balsa), 7 rooms ‘ langerova (plywood S 1 mm), 8 — torsion actuator Aileron, 9 — rear auxiliary spar (balsa s 5 mm), 10 — the leading edge of the Aileron (balsa), 11 — additional pin fixation console, 12 — drive coupling of Aileron, 13 — root rib (plywood).

The proposed trajectory of the course exercises

The proposed trajectory of the course of the exercise, “speed”:

1 — the entrance to the distance of the beginning of the countdown live span 2 — executing the half-rolls, 3 — run downward prolegli, 4 — the distance in the opposite direction, 5 — end of exercise. The dotted line shows the trajectory used.

Increasingly popular among modelers acquires in particular a new profile Е205. Even at relatively low Re numbers (100 000) coefficient of aerodynamic drag at low angles of attack almost two times lower than the Clark Y. Model with these planes will be advantageous in all exercises due to the increased value of the maximum quality. Attractive and low value of the torque coefficient more than two times different from the similar characteristics of the common Е387 (См0 for Е205 equal 0.048). This means lower losses , balancing apparatus, it is possible to significantly reduce the area of the horizontal tail, its weight and resistance. Important and simple lines bow profile: 70% of the chord from the bottom run in a straight line, a straight tail and the upper half-bow at the site, usually reserved for the flaps or ailerons. Simplicity of shape allows to increase the accuracy of the profile, to simplify the technology of manufacturing, and considerable relative thickness Е205 (10.48 percent) to make the wings rigid and durable with a relatively small mass.

Profile templates, as a reverse for the final finishing of the surface of finished consoles, and for the manufacture of the ribs (understated contour on the thickness of the plating) are performed only from sheet metal, for example, of aluminum, of a thickness of 1.5—2 mm. Marking and avilovka are carried out with maximum achievable accuracy. Any effort to improve, not to be redundant.

Excellent results are obtained when the technology of construction of the wings is proposed and successfully applied in the practice of timed models of the famous Soviet athlete E. Verbitsky.

Assembled frame is sheathed console-pre-prepared panels, which is a calibrated thickness sheets of balsa, covered outside aluminum foil thickness of 0.03 mm on the compound K-.153. By weight of such a “finish” of the surface is comparable to glass fiber cording. Exceptional rigidity of the consoles, the complete absence of any distortion in the shape of a thin wing even with the most prolonged use can consider a thin aluminum the best material for stitched. And the surface quality can be obtained arbitrarily high, which is important when using laminarizing profiles: flow by the air flow depends on the roughness of the body.

In any close-fitting balsa between the panels in place the rear edge of the padded tape of thin glass with a width of 40 mm, the reinforcing and supporting knife-like part.

The wing spar, rather, its shelves, variable cross-section — from 3X12 mm in the wing root to 3X5 mm at the end of the console. They are made of high quality grained pine. In the Central part between the shelves glued into the box under the metal tongues of the hinge wing on the fuselage, a significant portion of the spar sewn on both sides with plywood with a thickness of 1 mm. the Balsa wall is installed after assembling the frame of the wing. The balsa ribs with a thickness of 1.8 mm and sort them in a way that is closer to the fuselage was located made of a dense wood, light, leave the wing tips.

In the root part of the consoles glued FRP pipes, canisters, if necessary (mainly for exercise, “speed”) to fit the ballast rod casting. Actuator Aileron — torsion type. Rotating pull can be made from thin-walled dural tube Ø 5 X 0.5 or wire grade optical fiber Ø 3 mm. At the end it carries a quick connect coupler with d-pad included in the second node of the center section of the fuselage. This decision proved to be the most reliable. In all situations, when there was a reset consoles, the drive system of the ailerons did not require subsequent repair or adjustment. After putting on the wing on the languages of the sample it is additionally fixed by tightening the console with a rubber ring. Fittings in the root rib glue small but strong enough wire hooks.

Wing tip in the form of a flat bevel, increasing the effective angle of transverse V. It is much easier to manufacture than rounded, it allows you to leave the building, the angle V is very small, which has a positive effect in the flight model “on the back”.

Equally important for success and aerodynamic solution to the model as a whole. The minimum cross section of the fuselage, the absence of any cracks, ledges, the slightest surface defects, high quality exterior, correct execution of the fairings and wing joints of the control surfaces with the planes and tail, carefully podobrannye combination of handling and stability — only this will allow you to take full advantage of the profiles of Applera.

That’s why with no less attention should be given to the performance of other elements of the airframe. The nose part is laminated of fiberglass of (0.05, 0.25 and 0.05 mm) in the negative matrix. Butt joint passes through the vertical plane of symmetry of the fuselage, the canopy is cut from the finished bow with a thin blade from a jigsaw. The loop holes in the fuselage and a flashlight and fringes along the line of the joint with a frame made of plywood 3 mm thick Before assembling the fiberglass halves to them adjusted the frames and foam (material PVC) unit. In the last slotted recesses for stacking batteries, receiver and servos radio system that not only eliminates the need to install many shelves and brackets, to to that protects the equipment in critical situations.

Pay special attention to the set of nodes that specifies the position of the wing relative to the fuselage. The plane of the lower part of the contour of the ribs substantially parallel to the construction centerline, which provides the angle of attack of about 2°.

The tail section is fiberglass conical tube formed by winding three layers of fabric thickness of 0.05 mm on a supporting metal frame. With the nose she joined tubular fiberglass insert.

The design of the all-moving stabilizer:

1 — the leading edge (balsa 6 X 8mm), 2 — boss front pin (beech), 3 — lining (0.8 mm balsa S), 4, 7 — rib (balsa S 1 mm), 5 —tube hitch stabilizer Ø 4 X 0.2 mm, 6 — spar (balsa’s 3 mm), 8 — trailing edge (balsa 3 X 12 mm).

A TABLE OF THE COORDINATES OF THE PROFILE

It should be noted that the fuselages, produced by the new technique of two separate parts, well established n in operation.

The design of the tail is clear from the drawing. The only thing I would like to advise save every gram. Easy the tail of the device is the key to its good controllability and stability.

Ready-made model elements have the following mass: wing (both consoles) — 680 g fuselage keel without instruments — 240 g, the stabilizer with pins — 40 For the equipment there are more than 600 g, it means that you can use and improvised.

During debugging control system, verify that all the controls are easy to move, whether there is no backlash in the joints of tie rods with the control horns and the coupling of the drive of the ailerons. All-moving stabilizer should deviate by 10° in both directions, rudder — 20-25°. Last mated with the ailerons deflecting up and down at different angles (+24°, -15°), which is achieved by forward tilt of the pylon, located in the center section.

Stabilizer exhibited with zero angle of attack relative to the axis of the model, only when performing the first exercise, he lowered the trim tabs at — 1°. Folding canopy-brake opens at 35°, and large angles cause the appearance of the pitching moment. But at these values, the inhibition model is very effective.

In conclusion, I would like to acquaint modelers with interesting methods of exercise “speed” As shown by calculations and confirmed in practice, spectacular dive Vered entrance on the measuring distance for acceleration of a glider, flying at a low altitude on the horizon with the subsequent attack and combat u-turn to reverse course contain a lot of elements on which a significant portion of the potential energy accumulated at the start, lost is meaningless. This is especially true of reversal: perform it related to the growth of aerodynamic resistance of the model.

The design of the fuselage:

1 — foam block, 2 — batteries, 3 — single tray servos, 4 — servos, 5 — folding lantern-brake, 6 — node sample of the lantern, 7 — receiver control system, 8 — dural box mounting of languages, 9 — power frame, 10 — hole wiring rubber ring, 11 — fuselage drive unit Aileron with the control horns, 12 — additional frame, 13 — drive cables of the tail controls in budanovoy shell, 14 — front edge of the keel (balsa), 15 — strengthening the edges 16 — wall power box keel (plywood S 0,6 mm) 17 — the horn of the rudder 18 — mounting window 19 g— bulkhead mounting budanovoy sheath cables, 20 — tail boom of the fuselage, 21 insert, 22 — the nose of the fuselage vyklicky, 23 ~ towing hook 24 — beech boss fixing Board, 25 — language linkage console (D16T), 26 — wing (balsa), a 27 — rib of the center section (plywood B 2 mm), 28 — sheathing of the keel (balsa’s 1.5 mm), 29, 31 — plywood lining, 30 — tube-axle (stainless steel Ø 4.5 X 0.5, sealed in the keel), 32 — rocking allopourinola stabilizer (D16T 2 mm), 33 — unit junction cable with a rocking chair, 34 — rear pin hitch stabilizer (wire OVS Ø 3.5 mm), 35 — front pin hitch stabilizer (wire OVS Ø 2 mm) 36 — the trailing edge of the keel (balsa s 4 mm), 37 — the leading edge of the rudder (balsa), 38 — rib (balsa S 1 mm), 39 is the trailing edge of the rudder (balsa 3 X 12 mm).

Rational not to seek to gain the maximum height. Loaded ballast model still not released in full Leer. In moderate height the last seconds of the winch should not be used on sluggish rise, and the additional acceleration of the glider. He seems to be fired directly at a distance, having not only greater speed but also enough headroom height. It follows a steep decline (acceleration), during the forward passage of the measuring base running stretched a half-roll. By the end of the first flight model is in position “on back”. Some do not bring it to the end of the base, abruptly give up, no elevators. The apparatus through a downward half-loop (still overclocking!), going a little beyond the mark, goes into a normal flight back, again with the decline and dispersal. As you can see, senseless plots of braking on this path, no!

THE BASIC DATA MODEL

Scale, mm . . ………….2400

Wing area, DMG…..52,3

The surface of the stabilizer, dm2 . . 6,0

Takeoff weight, g……1600

Ballast weight, g ….. . 1000

Load unit, GS/dm2 ……… 30,6-49,7

A. DMITRIEV, master of sports of the USSR

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