I had a drawing of this model for several years. Knowing that it flies well, for some reason I could not decide to build it. The drawing was published in one of the Czech magazines in the early 80s. Unfortunately, I could not find out either the name of the journal or the year of publication. The only information that is present on the drawing is the name of the model (Sagitta 2m F3B), the date - either of construction or of the drawing - 10.1983, and, apparently, the name and surname of the author is Lee Renaud. Everything. No more data.
When the question arose of building a glider more or less equally suitable for flying both in thermals and in dynamics, I remembered the blueprint lying idle. One careful consideration of the design was enough to understand that this model is very close to the desired compromise. Thus, the problem of choosing a model was solved.
Even if I have at my disposal a drawing of some model ready for use, I still draw it with my own hand, with a pencil on graph paper. This helps to thoroughly understand the structure of the model and simplifies the assembly process - you can immediately develop the sequence of manufacturing parts and their subsequent installation. Therefore, the construction began with a drawing board. Minor changes were made to the design of the airframe, which made it possible to fearlessly tighten the model both on the rail and on the winch.
Intensive operation of the glider in the summer of 2003 showed that it is predictable, stable and, at the same time, agile - even without ailerons. The glider behaves quite satisfactorily both in thermals, allowing you to gain height even in weak flows, and in dynamics. I note that the model turned out to be too light, and sometimes the airframe needs to be loaded - from 50 to 200 grams. For flights in strong dynamic flows, the glider has to be loaded more - by 300 ... 350 grams.
For beginners, the model can only be recommended if the training is carried out in conjunction with an instructor. The fact is that the model has a relatively weak tail boom and nose. This does not cause any problems if you somehow know how to land a glider, but the model may not withstand a strong blow to the ground with its nose.
Characteristics
The main characteristics of the airframe are as follows:
Materials required for crafting:
- Balsa 6x100x1000 mm, 2 sheets
- Balsa 3 x 100 x 1000 mm, 2 sheets
- Balsa 2 х100х1000 mm, 1 sheet
- Balsa 1.5 x100x1000 mm, 4 sheets
- Duralumin plate 300x15x2 mm
- Small pieces of plywood 2 mm thick - approximately 150x250 mm.
- Thick and liquid cyacrine - 25 ml each. Thirty minute epoxy.
- Film for covering the model - 2 rolls.
- Small pieces of 8 and 15 mm balsa - approximately 100x100 mm.
- Pieces of textolite with a thickness of 1 and 2 mm - 50x50 mm is enough.
The production of the glider takes less than two weeks.
The design of the model is very simple and technologically advanced. The most complex and critical components - the attachment of the consoles to the fuselage and the swing arm of the all-moving stabilizer - will require maximum accuracy and attention when building the model. Carefully study the airframe design and assembly technology before proceeding with its construction - then you will not waste time on alterations.
The description of the model is designed for modellers who already have basic skills in building radio-controlled models. Therefore, constant reminders "check the absence of distortions", "carefully do [something]" from the text are excluded. Accuracy and constant control - things for granted.
Manufacturing
Note that, unless otherwise noted in the text, all balsa pieces have fibers along the longer side of the piece.
Fuselage and tail
Let's start building the glider with the fuselage. It has a square section; made of balsa 3 mm thick.
Take a look at the drawing. The fuselage is formed by four balsa plates 3 mm thick - these are two walls 1, as well as the top 2 and bottom 3 covers. All frames 4-8, except for frame 7, are made of 3 mm thick balsa.
Having cut out all the necessary details, we will tinker with the manufacture of frame 7 from three- or four-millimeter plywood. After that, having installed the frames on the drawing covered with a transparent film, we glue the walls to them. Having removed the resulting box from the drawing, we glue the bottom cover of the fuselage, and then lay the bowdens 9 for controlling the elevator and rudder (and, if desired, a tube for laying the antenna).
Let's take a look at the forward part of the fuselage. We will collect the nasal boss 10 from scraps of thick balsa, a removable lantern - from balsa with a thickness of 3 (walls 11) and 6 (upper part 12) millimeters. Control equipment is not installed yet. The only thing to do is to try it on in place. If necessary, you can remove frame 6, which is more of a technological than a power element.
We pass to the middle part of the fuselage, to which the wing is attached. We have to make a plywood box 13, linking together the wing spar, the fuselage itself and the towing hook. The details of the box are shown on a separate sketch. It consists of two walls 13.1 and a bottom, represented by a re-glue of parts 13.2 and 13.3. We stock up on two-millimeter plywood, a pair of jigsaw files - and start.
Having assembled the box "dry", we adjust it to the inside of the fuselage, and then glue it. We will make cuts for the connecting guide of the consoles later, in place. In place, other holes are made in the box.
After mounting the box, you can glue the top cover of the fuselage 2.
One of the most difficult stages of the fuselage assembly begins - the manufacture, fitting and installation of the keel and stabilizer rocker.
As you can see from the drawing, the keel (it is quite small, since the rest is the rudder) is formed by a frame of front 14, rear 16 and top 15 edges, made of two-millimeter balsa and glued between the sides of the fuselage.
The stabilizer rocker 17 is mounted in the frame, and then the side lining is glued to the frame - the walls of the keel 18 are made of balsa 3 mm thick.
Removable halves of the stabilizer are attached to the power pin 19 of steel wire 3 mm in diameter, and driven by a short pin 20 (steel wire 2 mm) glued into the front of the rocker. The rocking chair is made of textolite 2 mm thick, or plywood of the same thickness. Between the rocking chair and the walls of the keel, thin washers are installed, dressed on a power pin.
In appearance, everything is simple - we cut out all the details and assemble them together. Be extremely careful!!! Once the keel frame is assembled and the trim is glued to one side, you will begin to install the elevator arm, connect the bowden to it, and get ready to glue the keel wall on the other side.
This is where the main ambush awaits you: if even a drop of cyacrine gets on the rocking chair, which is installed between the walls of the keel without large gaps, write wasted. The rocking chair will dry up tightly to the wall, and the keel assembly will have to be repeated again. You should be especially careful when gluing a power three-millimeter steel pin - cyacrine can very easily get inside the keel through it. Use thick glue.
After assembling the keel, do not forget to glue the textolite pads 21, which fix the power pin from skew.
In conclusion, we will install forkil 22 and skin the fuselage.
The assembly of the rudder and stabilizer is so simple that it does not present any difficulties. I will only note that the holes for the power pin in the halves of the stabilizer after drilling are impregnated with liquid cyacrine, and then re-drilled.
Note that the fronts of the rudders are made from solid pieces of balsa (8mm thick on the rudder and 6mm thick on the stabilizer). This greatly simplifies the process of assembling the model, but does not add extra mass, because, as already mentioned, the glider is too light without it.
Having assembled and profiled the rudders, "roughly" hang them in their places and check the ease of movement. Everything is fine? Then we will remove them, put them away and move on to the wing.
Wing
The design of the wing is so standard that it should not raise any questions at all. This is a type-setting balsa frame with a forehead 8 sewn with balsa 1.5 ... 2 mm thick, ribs 1-7 from two-millimeter balsa with shelves made of balsa 1.5 ... 2 mm thick, and a wide rear edge 11 (balsa 6x25). Spars 9 - pine slats with a section of 6x3 mm, a wall of balsa 10 with a thickness of 1.5 ... 2 mm is mounted between them.
It should be noted that the spar, in general, will be flimsy for such a scale - in case you have to tighten the glider on a winch. For manual tightening, its strength is quite sufficient.
I, in order to avoid "firewood", had to glue strips of carbon fabric on outside each of the shelves of the spar. After such an improvement, the glider allowed itself to be pulled on a modern winch for gliders of the F3B class. The consoles, of course, bend, but they hold the load. As long as they keep it, at least...
Wing assembly begins with the manufacture of ribs. The ribs of the center section are processed in a "package" or "package". This is done as follows: we will make two rib templates from plywood 2 ... 3 mm thick, cut out the rib blanks and assemble this package together using M2 threaded studs, placing the templates along the edges of the package. After processing, such a solution will provide the same profile over the entire span of the center section. In the drawing, the center section ribs are numbered "1", and the ribs of the ears are numbered from "2" to "7".
With the ribs of the "ears" we will do differently. Having printed them on a laser printer with maximum contrast, we will attach the printout to a balsa sheet from which we will cut the ribs. After that, we will iron the printout with a heated "to the full" iron, and the images of the ribs will be transferred to the balsa. Do not forget only that the paper must be laid with the image on the balsa, and it is better to sand the balsa itself with a fine sandpaper first. Now we can start cutting out the printed parts. At the same time, prepare the details of sewing the forehead 8 and the center section 12, cut the strips of balsa for the shelves of the ribs 14, prepare the blanks of the front edges 13 and the walls of the spar 10, profile the rear edges 11. Please note that the walls of the spar 10 have a direction of wood fibers different from other parts - along the short sides. Upon completion of the preparation, we can start assembling the wing, without being distracted by the manufacture of the required parts.
First we make the center sections. We fasten the lower shelf of the spar to the drawing, install the ribs on it and install the upper shelf of the spar. Then we glue the walls of the spar of three-millimeter balsa 15, located in the root of the wing. After that, we wrap the resulting box with threads. Lubricate the threads with glue.
We will carry out a similar operation on the other side of the console - where the "ear" will be attached. Only the walls in this case will be made of two-millimeter balsa. Having glued the balsa walls of the spar, we wrap the resulting box. In the future, it will include the guide for attaching the "ear"
Please note that the root rib adjacent to the center section is not installed perpendicular to the spar and edges, but at a slight angle.
The next step is gluing the trailing edge. Needless to say, this operation, as well as the next one, is also carried out on the slipway.
We assemble the front part of the wing. The order is as follows: the bottom lining, then the top, then the wall of the spar of balsa 1.5 or 2 mm thick. Having removed the resulting console from the slipway, we glue the leading edge 13. Pay attention to how the wing strength for twist increases sharply after the “closing” of the forehead.
The final stage of the center section assembly is gluing the rib shelves and balsa lining of the wing root (three central ribs).
The assembly of the "ear" is completely similar to the assembly of the center section and therefore is not described. The only thing worth noting is that the rib adjacent to the center section is not installed vertically relative to the wing plane, but at an angle of 6 degrees - so that there is no gap between the "ear" and the center section. The root part of the "ear" spar is again wrapped with threads with glue.
Now let's pick up a narrow long knife and a needle file. We have to make holes for the guides of the center section 15 and the "ear" 16 in the boxes formed by the spar and its walls - two in the center section and one in the "ear". Having cut through the balsa end ribs, we level the inner surface of the boxes with a needle file. We do not glue the "ear" with the center section yet. Completely similarly, we assemble the second console and proceed to the manufacture of guides.
The center section guide bears the entire load applied by the lifeline to the model during tightening. Therefore, it is based on a strip of duralumin 2 ... 3 mm thick. It is processed in such a way as to enter the box designed for it without effort and backlash. After that, a plywood overlay similar in shape is glued to it with a thirty-minute resin, one or two - it depends on the thickness of the used duralumin and plywood. The finished guide is processed so that both consoles are put on it with little effort.
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The rails for attaching the "ears" to the center sections of the wing are made from three pieces of 2mm plywood glued together to give a total thickness of 6mm. After you make the guides for the "ears", the "ears" can be glued to the center sections. It is best to use epoxy for this.
It remains only to glue the "tongues" 17 and the fixing pins of the consoles 18. For the "tongues" two-millimeter plywood is used, for the pins - beech, birch or thin-walled aluminum or steel tube.
That, in fact, is all. It remains only to cut out windows for the guide, "tongues" in the center section of the fuselage and drill holes for the wing fixing pins. Keep in mind that here it is necessary to control both the absence of mutual distortions between the wing and the stabilizer, as well as the identity of the mounting angles of the left and right consoles. Therefore, do everything slowly and take measurements carefully. Think about it: maybe there is a technology that is convenient for you that allows you to avoid possible flaws when cutting windows?
Final operations
Now you should make the cover of the center section of the fuselage compartment 23. It is made of balsa or plywood. The method of its fastening is arbitrary, it is only important that it be removable and firmly fixed in its place. After the cover is made, we drill a hole with a diameter of 3 mm in it and the connecting tongues. A pin with a diameter of 3 mm, inserted later into these holes, will not allow the consoles to move apart under loads.
To increase the strength of the fuselage at the point of attachment of the wing guide, we will have to make another structural element 24, formed by four struts inside the fuselage, made of 3mm plywood. Inserting guide 15 into the holes prepared for it, glue these spacers close to it. We got a certain "channel" for the guide. He will not let her walk too freely in the holes and at the same time add rigidity to the fuselage. Glue the fifth piece of the "three-ruble note" about 100 mm closer to the tail. It turned out that the balsa fuselage in the center section was reinforced with a closed plywood box. This scheme has fully justified itself in practice.
Now it's time to glue and process the ends of the "ears" 19. After that, you can start balancing the model, and check if one of the consoles outweighs.
The fit of the airframe is not too complicated. If you are doing this for the first time, read the instructions for using the film. It, as a rule, describes in detail how to use this particular film.
Installation of radio control equipment should not cause any particular difficulties - just look at the photos.
Do not forget that the stabilizer on the model is all-moving. Its deviations in each direction should be 5 ... 6 degrees. And even with such expenses, it may turn out to be too effective, and the model - "twitchy".
The angles of deflection of the rudder should be 15 ... 20 degrees. It is advisable to seal the gap between the rudder and the keel with adhesive tape. This will slightly increase the efficiency of the steering wheel.
The towing hook 25 is made of a duralumin corner. Its installation location is indicated on the drawing.
From lead plates with a thickness of about 3 mm we will cut weights - in shape they should repeat the center section of the fuselage. The total weight of the "weight" should be at least 150 grams, and better - 200 ... 300. Using the number of plates in the fuselage, you can adjust the model to different weather conditions.
Don't forget to center the model. The location of the CG on the spar will be optimal for the first (and not only) flights.
The airframe described here was made without ailerons. If you think you can't live without them, put them on. If it does not seem - do not fool yourself, the model is controlled by the rudder quite normally.
However, the drawing shows the approximate size of the ailerons. You can think over the fasteners for the aileron steering machines yourself. Of course, from the point of view of aerodynamics and aesthetics, it is best to use minicars.
Flying
Tests
If you assembled the model without distortions, then there will be no special problems with the tests. Having chosen a day with an even light wind, go to the field with thick grass. After assembling the model and checking the operation of all rudders, take a run and release the glider into the wind at a slight angle of descent or horizontally. The model aircraft must fly straight and respond to even slight rudder and elevator deviations. A properly tuned glider flies a minimum of 50 meters after a slight hand throw.
Start on the rail
When preparing to start from the rail, do not forget about the block. The glider is quite fast, and in light winds there may be problems with the lack of speed of the puller, even when pulling with a block.
The handrail diameter can be 1.0…1.5 mm, length - 150 meters. It is preferable to place a parachute at its end, rather than a flag - in this case, the wind will drag the lifeline back to the start, reducing the distance you or your assistant runs in search of the end of the lifeline.
After checking the functioning of the equipment, attach the model to the rail. After giving your assistant the command to start moving, hold the glider until you have enough strength. The assistant, meanwhile, must continue to run, stretching the lifeline. Release the glider. At the initial moment of takeoff, the elevator must be in neutral. When the glider gains 20..30 meters of height, you can slowly start to take the handle "on yourself". Do not take too much, otherwise the glider will leave the lifeline ahead of time. When the model aircraft reaches its maximum height, vigorously give the rudders down, introducing the model aircraft into a dive, and then back. This is the so-called "dynamostart". With some practice, you will realize that it allows you to gain a few more tens of meters in height.
Flight and landing
Keep in mind that with a sharp giving of the rudder in any direction, the glider is prone to some course buildup. This phenomenon is harmful in that it slightly slows down the model. Try to move the rudder stick in small smooth movements.
If the weather is almost calm, the glider can not be loaded. If you are having trouble flying upwind or getting into a thermal, add 100-150 grams to the model. Then you can choose the mass of the ballast more accurately.
Landing is usually not a problem. If you have built a glider without ailerons, try not to make large rolls low above the ground, because the model responds to rudder deflection with a delay.
Curiously, additional loading has practically no effect on the model's ability to hover. A fully loaded glider holds up well even in relatively weak updrafts. The longest flight time in thermals achieved during the operation of the model is 22 min 30 sec.
And the same additional load is simply necessary for flying in dynamic flows. For example, for a normal flight in the "dynam" in Koktebel, the glider had to be loaded to the maximum - by 350 grams. Only after that did he gain the ability to move normally against the wind and develop amazing speeds in a dynamic flow.
Conclusion
Over the past season, the model has shown itself to be a good glider for amateurs. However, this does not mean that it is completely devoid of flaws. Among them:
- too thick profile. It would be interesting to try using E387 or something similar on this airframe.
- lack of developed wing mechanization. Strictly speaking, initially the glider contained both ailerons and spoilers, but in order to simplify the design and develop precise landing skills, it was decided to abandon them.
Nevertheless, the rest of the airframe worked out "perfectly well".
Currently, an electric glider based on the described model is under construction. Differences in the reduced wing chord, modified profile, the presence of ailerons and flaps, fiberglass fuselage, and much more. Only the general geometry of the prototype has been preserved, and even then not everywhere. However, the future model is the topic of a separate article ...
For enjoyable reading, you can turn on your favorite radio below:
SCHEMATIC MODELS OF THE AIRPLANE AND Glider
Soviet aircraft modelers built hundreds of the most interesting models of aircraft and gliders, from schematic to jet and radio-controlled.
The schematic model is the first step into "small aircraft". Schematic models of this class are called because they basically reproduce only the scheme of a real aircraft or glider. Such a model aircraft, equipped with a rubber motor, can fly a distance of at least 75 meters. A well-made glider model stays in the air for up to an hour.
The design of the described glider and aircraft models is so simple that it can be built in a school aircraft modeling circle, in a pioneer camp or at home. The main details of the model: wings, stabilizers, keels and others are made from ordinary pine planks. The pine going to these parts must meet the most elementary requirements - to be straight-grained, without knots, dry and not resinous.
To build models, it is enough to have: a planer, penknife, pliers, round nose pliers, a file and scissors.
SCHEMATIC MODEL OF THE Glider
Working drawings of the airframe model are given on sheet No. 1.
The main dimensions of the model:
wingspan - 940 mm,
model length - 1000 mm,
flight weight - 150 g.
The model, like a real glider, does not have a motor. She makes a flight, supported by oncoming air currents.
SCHEMATIC MODEL OF THE AIRCRAFT
Sheet No. 2 shows the complete working drawings of the model.
The dimensions of all parts and details are given in actual size.
The main dimensions of the model:
wingspan - 680 mm,
model length - 900 mm,
flight weight - 75 g,
screw size 240 mm.
A rubber motor is used as the engine. The propeller installation consists of a propeller with an axle mounted in a bearing and a rubber bundle. The rubber bundle is made of six threads of rubber with a section of 1 X 4 mm.
Before proceeding with the construction, carefully read the working drawings of the model and the text. Prepare necessary material and tool.
HOW TO USE THE DRAWINGS.
Our drawings are working, and all the details on them are drawn in full size. Therefore, in order to set the size of a particular part, it can be superimposed directly on the drawing.
PROCEDURE FOR MANUFACTURING PARTS OF THE MODEL.
When building models, you should go from simpler parts to more complex ones. First, cut out the rail, then make the keel, followed by the stabilizer, and then proceed to the manufacture of the wing.
HOW TO BEND PINE EDGES.
To make roundings of the wing, stabilizer and keel from pine planks, make a blank, and to bend the ribs (wing cross bars) - a template. The method will be as follows: planochki planed according to the drawing are steamed in boiling water for 5-10 minutes, and then bent on a blank, their ends are tied and left in this position until completely dry. The ribs are bent on a special template (see drawing) and fixed on it with a tin bracket until dry.
JOINTING ROUNDINGS WITH EDGES.
To splice the curves of the wing, stabilizer, keel with the corresponding edges, cut their ends obliquely so that when they overlap each other, they do not exceed the section of the edge. Lubricate the splices of the rounded edges with glue and tie tightly with a thread.
HOW TO PAPER WING AND TAIL.
Before pasting, the model is assembled and its parts are verified. After the distortions of the stabilizer wing and keel are eliminated, they are covered with tissue paper. Wings and stabilizer on the top side, keel on both sides. Tighten the wing with two people. Holding the paper by the corners, place it over the glued wing and smooth it over the ribs and edges. The paper is glued first on one half of the wing to the central rib, and then on the second part. Make sure that wrinkles do not form during tightening. After the glue dries, cut off the excess paper with a knife or fine glass skin. Sprinkle the covered wing and tail unit with mist.
ADJUSTMENT AND STARTING MODELS.
Before launching a model glider or aircraft, it must be adjusted. To do this, take the model behind the wing by the fuselage rail and, pointing slightly down, release it from your hand by slightly pushing it forward. The model should fly 10-12 meters. If the model lifts its nose up, move the wing back a little; if the model is too steep to land, move the wing forward. When flying the model with a list to the right or to the left wing, align the keel or straighten the wing as it is warped. If the model turns to the right or left during flight, adjust the keel turns.
Glider or Motor Glider? Non-motorized gliding flight has long attracted man. It would seem, what is easier - he attached wings to his back, jumped down from the mountain and ... flew. Alas, numerous attempts to take to the air, described in historical chronicles, led to success only in late XIX century. The first glider pilot was the German engineer Otto Lilienthal, who created a balancing glider, a very dangerous aircraft for flying. In the end, Lilienthal's glider killed its creator and brought a lot of trouble to enthusiasts of gliding flight.
A serious disadvantage of the balanced glider was the method of control, in which the pilot had to move the center of gravity of his body. At the same time, the device from obedient could turn into completely unstable in seconds, which led to accidents.
A significant change in the planning aircraft was made by the brothers Wilber and Orville Wright, who created an aerodynamic control system consisting of elevators, a rudder and a device for warping (gauching) the ends of the wing, which was soon replaced by more efficient ailerons.
The rapid development of gliding began in the 1920s, when thousands of amateurs came to aviation. It was then that hundreds of varieties of non-motorized aircraft were developed by amateur designers in many countries.
In the 1930s - 1950s, glider designs were constantly improved. Characteristic was the use of cantilever - without braces and struts - wings of high elongation, streamlined fuselages, as well as landing gear, retractable inside the fuselage. However, in the manufacture of gliders, wood and canvas were still used.
(wing area-12.24 m2; empty weight -120 kg; take-off weight - 200 kg; flight centering - 25%; Maximum speed - 170 km / h; stall speed - 40 km / h; sink rate -0.8 m / s; maximum aerodynamic quality-20):
1 – folding (sideways to the right) part of the lantern; 2- air pressure receiver of the speed indicator; 3 - starting hook; 4 - landing ski; 5 - brace (pipe from 30KhGSA 45X1.5); 6 - brake shield; 7 - box-shaped spar of the wing (shelves - pine, walls - birch plywood); 8 – wing profile DFS-Р9-14, 13.8%; 9 - box-shaped plywood beam; 10 - speed indicator; 11 - altimeter; 12 - slip indicator; 13 - variometer; 14 - rubber shock absorber skis; 15 - parachute PNL; 16 - wheel d300x125
ANB-M - single-seat glider: wing area - 10.5 m2; empty weight - 70 kg; take-off weight - 145 kg.
NSA-Ya - two-seat spark glider
A - fiberglass "Pelican": wing area -10.67 m2; empty weight - 85 kg; takeoff weight - 185 kg; stall speed - 50 km / h.
B-glider "Foma" V. Markov (Irkutsk): empty weight - 85 kg
A-KAI-502: wingspan-11 m; wing area - 13.2 m2; wing profile -РША- 15%; empty weight -110 kg; takeoff weight-260 kg; stall speed - 52 km / h; optimal planning speed - 70 km / h; maximum aerodynamic quality - 14; the minimum rate of descent is -1.3 m/s.
B - glider "Youth": wingspan - 10 m; wing area - 13m2; wing profile - RIA - 14%; empty weight - 95 kg; takeoff weight - 245 kg; stall speed - 50 km / h; optimal planning speed - 70 km/h; maximum aerodynamic quality - 13; the minimum rate of descent is -1.3 m/s.
B - single-seat glider UT-3: wingspan - 9.5 m; wing area - 11.9 m2; wing profile - RSHA-15%; empty weight - 102 kg; takeoff weight - 177 kg; stall speed - 50 km / h; optimal planning speed - 65 km / h; maximum aerodynamic quality - 12; minimum descent speed - 1m/s
A real revolution in gliding occurred in the late 1960s, when composite materials appeared, consisting of fiberglass and a binder (epoxy or polyester resin). Moreover, the success of plastic gliders was ensured not so much by new materials as by new technologies for manufacturing aircraft elements from them.
Interestingly, gliders made of composite materials turned out to be heavier than wooden and metal ones. However, the high accuracy of reproduction of the theoretical contours of aerodynamic surfaces and the excellent external finish provided by new technology, made it possible to significantly increase the aerodynamic quality of gliders. By the way, when moving from metal to composites, the aerodynamic quality increased by 20 - 30 percent. At the same time, the mass of the airframe structure increased, which led to an increase in flight speed, however, the high aerodynamic quality made it possible to significantly reduce the vertical rate of descent. This is what allowed the “composite” glider pilots to win competitions against those who competed on wooden or metal gliders. As a result, modern glider athletes fly exclusively in composite gliders and airplanes.
The technology of manufacturing composite structures is now widely used in the creation of light, including amateur aircraft and motor gliders, so it makes sense to talk about it in more detail.
The main elements of a modern glider wing are a box-shaped or I-section spar, which perceives bending and shearing force, as well as the upper and lower load-bearing skin panels, which perceive loads from torsion of the wing.
The construction of the wing begins with the manufacture of dies for molding the cladding panels. First, a wooden blank is made, which exactly reproduces the outer contours of the panel. At the same time, the impeccability of theoretical contours and the cleanliness of the surface of the blank will determine the accuracy and smoothness of the surfaces of future panels.
After applying a separating layer to the blank, panels of coarse fiberglass impregnated with an epoxy binder are laid out. At the same time, a power frame welded from thin-walled steel pipes or angle profiles. After the resin has cured, the resulting crust-matrix is removed from the blank and placed on a suitable stand.
Matrices for the upper and lower panels, stabilizer, left and right fuselage sidewalls are made in a similar way, which are usually made integral with the keel. The panels have a three-layer "sandwich" type construction - their inner and outer surfaces are made of fiberglass, the inner filler is foam. Its thickness, depending on the size of the panel, is from 3 to 10 mm. The inner and outer skin is laid out from several layers of fiberglass with a thickness of 0.05 to 0.25 mm. The total thickness of the glass fabric "crusts" is determined when calculating the strength of the structure.
In the manufacture of the wing, all layers of fiberglass that make up the outer skin are first molded into the matrix. Pre-fiberglass is impregnated with an epoxy binder - most often, amateurs use K-153 resin. Then, the foam filler, cut into strips from 40 to 60 mm, is quickly spread on the fiberglass, after which the foam is covered with an inner layer of fiberglass impregnated with a binder. In order to avoid wrinkles, fiberglass skins are manually leveled and smoothed.
Next, the resulting “semi-finished product” must be covered with an airtight film with a fitting cut into it and glued with a sealant (or even just plasticine) to the edges of the matrix. Further, air is pumped out through the fitting from under the film with a vacuum pump - at the same time, the entire panel set is tightly squeezed and pressed against the matrix. In this form, the set is kept until the final polymerization of the binder.
Glider "Kakadu" (wing area - 8.2 m2; wing profile - PSHA - 15%, empty weight - 80 kg; takeoff weight - 155 kg):
1 - rear spar of the wing (consists of a wall with foam filler, glued on both sides with fiberglass, and fiberglass shelves); 2 - PS-4 foam filler; 3 - fiberglass shelf of the spar (2 pcs.); 4 - fiberglass assembly of the aileron; 5 – fiberglass tubular aileron spar (wall thickness 0.5 mm); 6 - three-layer panels forming the aileron skin (filler - PS-4 foam plastic 5 mm thick, the thickness of the fiberglass crust on the outside is 0.4 mm, on the inside - 0.3 mm); 7 - fuselage beam; 8 - shelf of the fuselage beam (fiberglass 3 mm thick); 9 - fiberglass sheathing 1 mm thick; 10 – PS-4 foam block; 11 - fiberglass lining of the wing toe with a thickness of 0.5 to 1.5 mm, forming a torsionally working contour; 12 - typical wing rib; 13 - fiberglass shelf rib 1 mm thick; 14 - fiberglass wall of the rib 0.3 mm thick; 15 – front spar of the wing (similar in design to the rear)
A - training glider A-10B "Berkut":
wing area -10 m2; empty weight - 107.5 kg; takeoff weight - 190 kg; maximum speed 190 km/h; stall speed - 45 km / h; maximum aerodynamic quality - 22; operating overload range - from +5 to -2.5; design overload - 10.
B - A-10A motor glider with an air-cooled engine "Vikhr-30-Aero" with a power of 21 hp. In flight, the power plant can be retracted into a compartment located in the middle part of the fuselage.
Motor glider length - 5.6 m; wingspan - 9.3 m; wing area - 9.2 m2; takeoff weight - 220 kg; maximum speed - 180 km / h; stall speed - 55 km / h; maximum aerodynamic quality - 19; propeller diameter - 0.98 m; propeller pitch - 0.4 m, propeller speed - 5000 rpm
engine - "Kolibri-350" home-made, two-cylinder, boxer, 15 hp; motor glider length - 5.25 m; wingspan -9 m, wing area - 12.6 m2; wing profile - R-P - 14%; hovering aileron profile - R-Sh - 16%; empty weight - 135 kg; takeoff weight - 221 kg; maximum speed -100 km / h; cruising speed - 65 km / h; stall speed - 40 km / h; maximum lift-to-drag ratio -10
A similar technology is used in the manufacture of spars shelves, with the only difference that they are laid out from unidirectional glass or carbon fiber. The final assembly of the wing, empennage and fuselage is usually done in dies.
If necessary, spars, frames and ribs are inserted and glued into the finished molded three-layer panel, after which everything is covered and sealed with the top panel.
Since there are large gaps between the parts of the internal set and the cladding panels, it is recommended to use epoxy glue with a filler, for example, glass microspheres, when gluing. The contour of gluing the panels from the outside (if possible, from the inside) is glued with glass cloth tape.
The gluing and assembly technology is described here only in general terms, but, as experience shows, amateur aircraft designers quickly comprehend its subtleties, especially if there is an opportunity to see how those who have already mastered this technique do it.
Unfortunately, the high cost of modern composite gliders has led to a decline in the mass gliding sport. Concerned about this, the International Aviation Sports Federation (FAI) introduced a number of simplified classes of gliders - standard, club and the like, whose wingspan should not exceed 15 meters. True, difficulties remain with the launch of such gliders - this requires towing aircraft or rather complex and expensive motorized winches. As a result, every year fewer and fewer gliders are brought to meetings of amateur aircraft designers. In addition, a significant part of the gliders are variations of the BRO-11 designed by B.I. Oshkinis.
Of course, building your first aircraft is best done in the image and likeness of a reliable, well-flying prototype. It is this kind of "copying" with a minimum amount of trial and error that gives that invaluable experience that cannot be acquired from textbooks, instructions and descriptions.
Nevertheless, original, more modern aircrafts, such as the ANB-M glider, created by P. Almurzin from the city of Samara.
Peter dreamed of "wings" since childhood. But poor eyesight prevented him from enrolling in a flight school and playing aviation sports. But every cloud has a silver lining - Peter entered the Aviation Institute, graduated from it and received a referral to an aircraft factory. It was there that he managed to organize a youth aviation design bureau, later transformed into the Flight club. And the most reliable assistants of Apmurzin were the students of the Aviation Institute, who were just as passionate as Peter, who dreamed of flying.
The first independently developed design of the club was a glider, made taking into account the technological features of modern aviation production - durable, simple and reliable, on which all members of the club could learn to fly.
The first glider was named NSA - after the initial letters of the names of its designers: Apmurzin, Nikitin, Bogatov. The wing and plumage of the apparatus had an unconventional for gliders of this class metal structure using thin-walled duralumin pipes of large diameter as spars. Only the fuselage on the original version of the airframe was made of composite materials. However, in the next version, the cabin was designed as a metal one, which made it possible to reduce its weight by 25–30 kg.
The creators of the airframe turned out to be not only competent designers, but also good technologists familiar with modern aviation production. So, in the manufacture of thin sheet parts from duralumin, they used a simple, well-established technological operation in aviation production - rubber stamping. The equipment needed for this was made by the young engineers themselves.
The gliders were assembled in the basement where the club was located. The flight characteristics of the new vehicles turned out to be close to the calculated ones. Soon all members of the club learned to fly on homemade gliders, having made dozens of solo flights from a motor winch. And at the ULA rallies, the gliders invariably received the highest appraisal from experts, who recognized the ANB-M as the best glider for initial training among serial and amateur designs. And the Polet club was presented with a new, more suitable room for work, and it was reorganized into the Sports Aviation Design Bureau at an aviation plant with a staff of five people.
Meanwhile, work on the modernization of the NSA airframe continued - its design was improved, static strength tests were carried out, and preparations were made for mass production of the device.
Everyone is good at flying on gliders with their launch using a motorized winch, however, such flights have one very significant drawback - short duration. Therefore, in the development of each team of amateur aviators, the transition from a glider to an airplane is quite natural.
Using the well-established design of the NSA glider and the technology of its production, young aircraft designers Almurzin, Nikitin, Safronov and Tsarkov designed and built a single-seat training aircraft "Crystal" ( detailed description the design of this machine - in the previous "lessons" of our school - in "M-K" No. 7 for 2013).
It should be noted that initial training gliders have always attracted both solo amateurs and design teams. So, one of the most beautiful training gliders that has ever been demonstrated at ALS rallies was recognized as the Kakadu, created by amateur aviators from the city of Otradnoye, Leningrad Region.
This glider is made from three types materials - foam, fiberglass and epoxy binder, and the design of the wing and plumage is a kind of small design masterpiece.
Wing ribs are made of foam plastic and covered with thin fiberglass. The toe of the wing, which perceives the torque, is a fiberglass shell glued on a foam block-filler. The fuselage beam is cut out of foam and glued with fiberglass, and the bending moment is perceived by fiberglass shelves glued to the upper and lower surfaces of the beam. The quality of work is excellent, the exterior finish is the envy of many do-it-yourselfers. The only "but" - the glider refused to fly - as it turned out, in an effort to reduce the mass of the structure, the creators of the glider unnecessarily reduced the wing.
Enthusiasts who have completed flight training on gliders of initial training can be recommended a more complex device, for example, the A-10B Berkut glider, created by students of the Samara Aviation Institute under the guidance of V. Miroshnik. Interestingly, in terms of its parameters, the glider does not correspond to any sports class, and in terms of its dimensions it is smaller than standard ones. At the same time, the A-10B has very clean aerodynamic shapes, a simple strut wing is covered with fabric, and the device itself is made of the most common plastics. A sufficiently large aerodynamic quality of the glider makes it possible to make even long soaring flights on it. A simple piloting technique allows even a beginner to cope with such a device. It seems that it is precisely such inexpensive and "flying" gliders that are lacking in domestic gliding.
A peculiar development of the ideas embodied in the A-10B was the Dream glider, created in a Moscow amateur club under the leadership of V. Fedorov. In terms of design, manufacturing technology and appearance"Dream" is a typical modern sports glider, and in terms of specific wing load and some other parameters, it is a typical glider of initial training. The “Dream” flies quite well, at the ULA rallies this glider was sent flying in tow from the “Vilga” aircraft.
It should be noted that flights of gliders launched from a shock absorber, winch or from a small mountain are extremely limited in time and do not bring the pilot proper satisfaction. Another thing is a motor glider! The device with a motor has much wider possibilities. Moreover, motor gliders, even with low-power engines, sometimes outperform some amateur-built light aircraft in terms of flight data.
The point, apparently, is that airplanes, as a rule, have a wingspan significantly less than that of a motor glider, and with a decrease in the wingspan, the loss in lift is greater than the gain in mass. As a result, some aircraft are unable to get off the ground. While training motor gliders with coarser aerodynamic shapes and low-power engines fly perfectly. The only difference between these aircraft and airplanes is the larger wingspan. I think that is why training motor gliders are especially popular with amateurs.
engine power - 36 l, s .; wing area - 11m2; empty weight - 170 kg; takeoff weight - 260 kg; flight centering - 28%; maximum speed - 150 km / h; stall speed - 48 km / h; rate of climb - 2.4 m / s; maximum aerodynamic quality - 15
motor glider length -5 m; wingspan -8 m; wing area - 10.6 m2; empty weight - 139 kg; takeoff weight - 215 kg; maximum speed -130 km / h; landing speed - 40 km / h; propeller speed - 5000 rpm);
1 - variometer; 2 - slip indicator; 3 - speed indicator; 4 - altimeter; 5 - pedals; 6 - air pressure receiver; 7 - tubular motor mount; 8 - engine; 9 - cable braces; 10 – rudder control cables; 11 – control rods of the Elevator; 12 - all-moving horizontal tail; 13 - tubular struts plumage; 14 - sections of the wing and plumage, covered with lavsan film; 15 - tail spring; 16 – fiberglass pilot's gondola; 17 – aileron control rods; 18 – main chassis spring; 19 - engine control wiring; 20 – fiberglass spring nose landing gear; 21 - wing spar; 22 – aileron attachment points; 23 - aileron (upper skin - fiberglass, lower - lavsan film); 24 - silencer; 25 – fuel tank; 26 - tubular wing strut
wing area - 16.3 m2; wing profile - modified GAW-1 - 15%; takeoff weight - 390 kg; empty weight - 200 kg; maximum speed -130 km / h; rate of climb - 2, 3 m / s; design overload - from + 10.2 to -5.1; maximum aerodynamic quality -25; propeller thrust - 70 kgf at 5000 rpm
wing area - 18.9 m2; takeoff weight - 817 kg; stall speed - 70 km / h; maximum horizontal flight speed-150 km / h
wingspan-12.725 m; front wing span - 4.68 m; motor glider length -5.86 m; front wing area - 1.73 m2; main wing area - 7.79 m2; empty weight - 172 kg; takeoff weight - 281 kg; maximum aerodynamic quality - 32; maximum speed - 213 km / h; stall speed - 60 km / h; flight range - 241 km; operating overload range from +7 to -3
Great success in creating the simplest such devices was achieved by students of the Kharkov Aviation Institute, who built the Korshun-M motor glider under the guidance of A. Barannikov, and later, under the guidance of N. Lavrova, a more advanced Enthusiast was created, which had good aerodynamic shapes, a closed cockpit and carefully hooded engine.
It should be noted that both of these motor gliders are a further development of the once popular training glider BRO-11 designed by B. Oshkinis. Apparatuses of Kharkov students have the simplest design without pretensions to originality, but they are very durable, reliable and easy to manage for novice pilots.
At one of the ULA rallies, C. Kishonas from Kaunas demonstrated one of the best motor gliders - "Garnis", made entirely of fiberglass. Sheathing of wings and plumage - transparent lavsan film. The power unit is a 25 hp Vikhr-M outboard motor, converted for air cooling. The motor is easily dismantled from the device.
The motor glider is equipped with several options for easily removable landing gear - a three-wheeled aircraft type, a single-wheeled glider and a float.
Motor gliders and gliders of the type "Kite" and "Garnis" are built in our country by many amateurs in dozens of copies. I would like to draw the attention of readers to only one feature of such devices, built in the image and likeness of BRO-11. As you know, the prototype (as well as its numerous copies) is equipped with hovering ailerons kinematically connected to the elevator. When landing, the pilot takes over the control stick, while the ailerons synchronously deviate down, which causes an increase in lift and a decrease in speed. But, if the pilot accidentally moved the stick towards himself, and then, correcting the situation, gave the stick away from himself, the last movement of the stick causes not only the elevator deflection, but also the return of the ailerons to their original position, which is tantamount to retracting the flaps. At the same time, the lifting force decreases sharply - and the glider "fails", which is very dangerous when flying at low altitude, before landing.
Experiments conducted by glider pilots flying the BRO-11 showed that without aileron hovering, the takeoff and landing characteristics of the glider practically do not deteriorate, but it is much easier to fly such a glider, which significantly reduces the accident rate. At the same time, for the wing of a low-speed motor glider, the convex-concave profile of the Göttingen F-17 may turn out to be more profitable - it was once used on the Phoenix-02 motor glider, created by TsAGI engineer S. Popov.
The popularity of motor gliders is primarily due to the possibility of their launch without special towing devices, as well as due to the appearance of simple, light and sufficiently powerful motors. A lot of original, spectacularly flying vehicles of this class, created by amateur designers, were demonstrated at the ALS rallies. The beautiful A-10A motor glider was built by V. Miroshnik on the basis of the A-10B already familiar to readers. His power unit is the Vikhr-25 engine, converted for air cooling; it is located above the fuselage, behind the cockpit. The engine, as a rule, was used only for takeoff and climb. After turning it off, a special mechanism folded the truss with the engine installed on it and removed it into the fuselage, which significantly reduced the aerodynamic drag of the aircraft. If necessary, the engine could be pulled out of the niche and started using the same mechanism.
Another aircraft built by students from the Samara Aviation Institute is the Aeroprakt-18 two-seat motor glider. It is compact, lightweight, made entirely of plastic and equipped with a 30-horsepower air-cooled Vikhr-30-aero engine - in this model the engine is not removed in flight, which made it possible to simplify and lighten the design.
However, amateur designers continued to develop original variants mechanisms for cleaning motors in flight, and one of these most interesting devices was created by a group of Moscow amateur aviators led by A. Fedorov for the Istra single-seat twin-engine motor glider. Light motors were completely inscribed in the contours of the wing, not protruding beyond its theoretical contours, and the propellers rotated in the slots behind the rear spar of the wing. When the engines were stopped, the propellers were fixed in a horizontal position and closed with a sliding wing tail.
Another development of Moscow amateur glider pilots is the Baikal two-seater motor glider, also equipped with two engines. True, they are not placed on the wing, but on a V-shaped pylon above the fuselage. In flight, the motors are retracted into the fuselage - just like on the Istra.
Feature motor gliders A. Fedorov - composite construction, made in accordance with the canons of modern technology.
It is generally accepted that the aerodynamic design of modern gliders and motor gliders has completely stabilized. Indeed, all modern devices of this type differ little from each other, and their geometric proportions are almost the same. Nevertheless, the design idea is looking for new solutions, other schemes and proportions. This was confirmed by the aircraft of Swiss designers and Bert Rutan's Solitar motor glider. These original canard powered gliders once again demonstrated the advantages of the horizontal tail unit.
In one of the old issues of the magazine "Pioneer" instructions, drawings and diagrams are given on how to make a simple model of an A-1 type glider with your own hands, at home.
airframe model flies without a motor and a propeller, smoothly descending, gliding, as if gliding in the air. It usually starts from the rail. Leer is a thick thread fifty meters long with a ring at the end. There is a hook on the glider model, and this ring is put on it.
The model must be launched against the wind. She, like kite, rushes up and rises to a height of about forty-five meters. At this point, the launcher loosens the line, the ring slips off the hook, and the model flies freely. When there is no wind, the launcher has to run a little with the rail so that the model rises to approximately the same height even in calm weather. If the model enters an updraft, it will not descend and may even begin to climb.
Glider models are different size. In aeromodelling, two types of models are most common: "A-2" and "A-1". "A-2" is a large model, with a wingspan of about two meters. Such models, if they are well adjusted, fly for two or three minutes, and sometimes they can even completely disappear from sight. But they are complex, only experienced aircraft modellers can build them.
With the help of adults, children can build smaller and simpler models - "A-1". The wingspan of this model is 1,000-1,200 millimeters, and it flies on average from one to two minutes. These models are subject to one indispensable requirement: the total area of the wing and its stabilizer must be no more than 18 square decimeters, and the weight in flight must not be less than 220 grams.
Pioneer airframe model
Details and materials-blanks
To build a model (Fig. 1), it is necessary to prepare the following blank materials in advance:
1. 18 plates of plywood 1 mm or 1.5 mm thick or cardboard 2 mm thick; size of each plate - 130X10 mm
2. Pine rail section 12X3 mm, length 1110 mm.
3. Pine rail section 5X4 mm, length 1110 mm mm.
4 a. Pine rail section 7X7 mm, length 650 mm.
4 b. 4 pine slats with a section of 7X3 mm, each 250 mm long.
5. 2 pine slats with a section of 10X2 mm, each 130 mm long.
6. 2 sheets of writing paper.
7. 1 sheet of plywood 3 mm thick or thick cardboard 4 mm thick, size 340X120 mm.
8. A sheet of plywood 3 mm thick or thick cardboard measuring 200X100 mm.
9. 2 pine slats with a section of 10x3 mm, each 700 mm long.
10. Pine plate 3 mm thick, 25X15 mm in size.
11. Pine rail with a section of 10x3 mm, length 130 mm.
12. Pine rail with a section of 5x2 mm, 150 mm long.
13. Pine lath with a section of 5x2 mm, 120 mm long.
14. 5 pine slats with a section of 3x2 mm, each 90 mm long.
15. Pine plate 2 mm thick, 100x25 mm in size.
16. 2 pine slats with a section of 3x2 mm, each 400 mm long.
17. Pine rail with a section of 3x2 mm, 85 mm long.
18. Pine block with a section of 5x3 mm, 120 mm long.
19. 2 sheets of tissue paper 400x500 mm for covering the wing and plumage.
20. Oak or bamboo pin 25 mm long, 4 mm in diameter.
21. Rubber band with a section of 1x4 mm, length 1,500 mm.
22. 30 nails 8 mm long.
23. Nitroglue, it can be replaced with casein or carpentry.
24. A stern thread 50 m long for a handrail with a ring at the end made of wire 1 mm thick.
A triangular flag made of cloth 300-400 mm long and 50 mm wide is attached to the handrail in front of the ring.
In all figures and in the text, details are designated by the same number. Each piece is made from a blank. To find out the dimensions of the workpiece from which the part must be made, look for the number in the list of workpieces that indicates the part.
How to make a glider: wing
According to template 1 (Fig. 2), cut out of cardboard, it is necessary to be as accurate as possible sharp knife or use a jigsaw to cut out 18 ribs from plywood or cardboard, giving the wing a certain profile. For convenience, it is better to knock all 18 blanks into a stack with cloves in advance and cut out all the ribs at the same time.
Then, for the trailing edge 2, it is necessary to cut the prepared rail with a planer into a triangular section and bend it over the fire of an alcohol lamp or a kerosene lamp in two places, stepping back 240 mm from each end so that the ends of the rail on the left and right would be raised 140 mm from the middle. Moisten the folds with water before bending.
After that, at the locations of the ribs (Fig. 3), make cuts with a hacksaw 2 mm deep and 1 mm wide (Fig. 2).
The leading edge 3 is made of pine lath; it curves in the same way as the trailing edge. Then, the main longitudinal part of the wing, the spar 4, is assembled from the rails 4a and 4b. The rail 4a must be cut off (its length is 650 mm) and glued at the ends and tied with threads of the rail 4b as shown in Figure 3. In this case, you need to follow so that the ends of these rails are raised 140 mm above the middle.
Now you need to mark with a pencil on the board according to the drawing (Fig. 5)
the position of the ribs, spar and edges and fasten the front, rear edges and spars with pins on the board (Fig. 6).
The ribs are put on over the spar, their ends are inserted into the slots in the trailing edge and the socks are pressed tightly against the leading edge.
All joints of wing parts must be carefully lubricated with glue. The trailing and leading edges are glued together at right angles by a rail 5, the ends of which are attached to the trailing and leading edges by means of paper overlays 6. For rigidity, paper squares must be glued at the fracture site of the wing leading edge.
After the glue has dried, it is necessary, by removing the pins, to remove the wing from the board and cut off one face of the leading edge with a sharp knife so that the leading edge does not protrude beyond the contour of the profile. Then check if the wing is skewed. If there is a warp, it can be eliminated by bending the wing over the electric stove.
Next, the wing must be covered with tissue paper 19. The straight central part of the wing and the end parts, bent upwards, must be covered separately. Moreover, the top and bottom of these parts are also covered separately: first the bottom, and then the top (Fig. 7).
After tightening, it is necessary to sprinkle the wing with water from a spray bottle and lay it on a flat board, lay supports under the ends of the wing, press the wing against them with some weights and leave to dry in this form (Fig. 8).
Fuselage and keel
The front part of the fuselage from plywood or cardboard is cut out according to Figure 9. On the toe of the front part, linings 8 are glued on both sides and seized with nails. At the top, make a pilot's cabin with a pilot, as shown in Figure 9.
Across the plane of the front part of the fuselage 7, a pin made of bamboo is fixed with glue. Then, from the sides of the front part of the fuselage, rails 9 are attached to the glue and nails as shown in Figure 4. On top of the rails 9, a pine plate 10, cut according to Figure 4, is also fixed on nails and glue. Between the rails 9 on the glue must be laid on a distance of 100 mm "crackers" 11, cut from a pine lath.
The keel is flat, it is assembled with glue from slats and paper squares on a flat board according to the dimensions shown in Figure 5: front edge 12, rear edge 13, top edge 14 and bottom edge 15 of pine plate.
Paper squares must first be glued on one side (Fig. 4), when the keel is pressed to the board with pins. Then the keel must be removed and the squares glued symmetrically on the other side. The assembled keel is installed between the fuselage rails 9 as shown in Figure 4. The joints are glued, and the rails are connected to the keel with two studs.
The lower part of the keel, protruding under the slats, is glued on both sides with writing paper, and the upper part of the keel is also covered with tissue paper on both sides.
Stabilizer
The stabilizer is assembled on a flat board in the same way as the keel.
The leading and trailing edges 16 and ribs 17 are made of pine slats. The dimensions of the stabilizer are shown in Figure 5. To attach the stabilizer to the fuselage, a pine block 18 is attached to it with glue and threads. The stabilizer is covered with tissue paper on top with a solid sheet.
Assembly and adjustment of the model
Put the wing on the fuselage and press it tightly with a rubber band 21. The stabilizer is inserted with a block 18 between the rails 9 and the rear of the fuselage.
In front of the stabilizer and behind it, the rails 9 must be tightly tied with a rubber band. Look at the model from the front: the stabilizer should be parallel to the wing, the wing and stabilizer should not be warped.
The assembled model of the glider must be balanced and checked if its center of gravity is correctly located. To do this, balance the model by holding the wing on two fingers. Your fingers should be approximately on the circle, which in Figure 5 indicates the center of gravity. If the tail of the model outweighs, pour shots into the nose of the fuselage.
regulate airframe model you must first over the grass or over the snow, launching it from your knee with a light push, and then switch to launching from your hands from full height. If the model lifts its nose at launch, you should gradually add loading to the fuselage nose or slightly reduce the wing angle by slightly cutting plate 10 from above.
If the model flies steeply with its nose down, it is necessary to increase the angle of the wing by making an additional thin lining on the same plate.
Having adjusted the model when starting from the hands, you can proceed to the launch from the rail. The rail ring is put on, like a hook, on the lower "horn" of the fuselage.
The model should be launched from the rail strictly against the wind, and the first launches should be made first in light wind.
I. Kostenko, Pioneer magazine, 1959
Tags: do-it-yourself glider, how to make a glider with your own hands at home, drawings, glider model.
The glider has smooth rounding of the wing, stabilizer and keel (Fig. 1). This form improves the flight performance of the model. In addition, all joints of parts are made with glue, without the use of metal corners. Thanks to this, the glider is very light, which improves its flight qualities.
And finally, the wing of this model is raised above the fuselage rail and is attached with wire racks. Such a device increases the stability of the model in flight.
Model work.
Let's start working on the model by drawing working drawings.
The fuselage of the model consists of a rail 700 mm long and with a section in the bow 10X6, and in the tail 7X5 mm. For the sinker, you need a plank 8-10 thick and 60 mm wide from pine or linden.
We cut out the weight with a knife and process its ends with a file and sandpaper. The front end of the rail will enter the ledge at the top of the weight.
Now let's start making the wing. Both of its edges should be 680 long and 4X4 mm in section. We will make two end roundings for the wing from aluminum wire with a diameter of 2 mm or from pine slats 250 mm long and 4X4 mm in section.
Soak the slats in hot water for 15-20 minutes before bending. Glass or tin cans or bottles of the desired bottom-meter can serve as a form for the manufacture of smooth roundings. In our model, the molds for the wing should have a diameter of 110 mm, and for the stabilizer and keel - 85 mm. Having steamed out the slats, wrap each of them tightly around the can and tie the ends together with an elastic band or thread. Curving like this right amount rails, leave them to dry (Fig. 2 a).
Rice. 2 Making a wing. a - obtaining roundings; b - connection "on the mustache"
Rounding can be done in another way. Draw a rounding on a separate sheet of paper and place this drawing on the board. Drive cloves along the contour of the rounding. Having tied the steamed rail to one of the studs, we will begin to carefully bend it. We will tie the ends of the rails together with an elastic band or thread and leave to dry completely.
We connect the ends of the roundings with the edges "on the mustache". To do this, we cut off the ends to be joined at a distance of 30 mm from each of them, as shown in Figure 2, b, and carefully fit them to each other so that there is no gap between them. Let's put a clamp on the joint, carefully wrap it with a thread and glue it again on top. It should be borne in mind that the longer the connection "by the mustache", the stronger it is.
We will bend the ribs for the wing on the machine. We will precisely mark the places of their installation according to the drawing. The wing after each operation (setting the rounding of the ribs) will be superimposed on the drawing to make sure that the assembly is correct.
Then we look at the wing from the end and check if any rib protrudes above the other “hump”.
After the glue dries at the junction of the ribs with the edges, it is necessary to give the wing a transverse angle V. Before bending, we soak the middle of the edges of the wing under the tap with a trickle hot water and heat the place of the bend over the fire of an alcohol lamp, candle or over a soldering iron.
We will not move the heated part above the flame, so that the rail does not break due to overheating. We will bend the rail until the place of heating remains hot, and release it only after it has cooled down.
We check the angle of the transverse V by attaching the wing end to the drawing. By bending one edge, we will bend the other in the same way. Let's check whether the angle of the transverse V is the same for both edges - it should be 8 ° on each side.
The wing mount consists of two V-shaped struts (struts), bent from steel wire with a diameter of 0.75-1.0 mm and a pine plank 140 mm long and 6X3 mm in section. The dimensions and shape of the struts are shown in fig. 3.
Rice. 3 Wing attachment.
The struts are attached to the edges of the wing with threads and glue. As can be seen from the figure, the front brace is higher than the rear. As a result, the installation angle of the wing is formed.
We will make the stabilizer from two rails 400 mm long, and the keel from one such rail.
We steam the slats and bend them, using a jar with a diameter of 85 - 90 mm as a form. In order to mount the stabilizer on the fuselage rail, we cut out a bar 110 mm long and 3 mm high. We will tie the front and rear edges of the stabilizer in the center with threads to this bar.
We will sharpen the ends of the keel rounding, in the bar next to the edges of the stabilizer we will make punctures-nests and insert the pointed ends of the keel into them (Fig. 4).
And now you can start covering the model with tissue paper. The wing and stabilizer will be pasted over only from above, and the keel - from both sides.
Model assembly.
Let's start assembling the model with the plumage: put the stabilizer on the rear end of the fuselage rail and wrap the front and rear ends with an elastic band connecting strip along with the rail.
To launch the model on the rail, we will make two hooks from steel wire and tie them with threads to the fuselage rail between the leading edge of the wing and the center of gravity of the model. The first launches of the model are feasible from the front hook.
Model launch.
After making sure that the launch is successful, you can run the model from the second hook.
It should be borne in mind that in windy weather it is better to launch the model from the front hook, and in quiet weather - from the back hook.
