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 - whether it was built or the drawing was made - 10.1983, and, apparently, the name and surname of the author is Lee Renaud. All. 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 a ready-to-use drawing of some model at my disposal, 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.
The removable halves of the stabilizer are mounted on a power pin 19 made of steel wire with a diameter of 3 mm, and are driven by a short pin 20 (steel wire 2 mm) glued into the front of the rocking chair. 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 up 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 (6x25 balsa). 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 the outside of each of the spar shelves. 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. By printing them on laser printer with maximum contrast, we will attach the printout to the 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 spacers inside the fuselage, made of 3 mm 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 a 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 ...
GLIDER
non-motorized aircraft heavier than air. The glider is kept in the air by balancing the downward force of gravity by the lift created by the upward air currents. There are two modes of glider flight: gliding (gliding) and soaring. Gliding is steady descent flight, which can be likened to rolling a sled or cart on wheels down a slope. Soaring is the use of the lifting force created by air currents and supporting the aircraft in the air. The first human flights using an aircraft heavier than air were carried out on gliders. These aircraft did not have a cockpit or landing gear. On some gliders (like those of the Wright brothers), the pilot lay on the platform, while on others (such as O. Lilienthal's glider), the pilot hung on his hands and controlled the flight with the movements of his body. After the First World War, training gliders were equipped with elevators, rudders and ailerons, which allowed the pilot to more effectively control the vertical, horizontal and transverse movements of the aircraft. But still, the pilot was still located in a chair that was not protected from air currents. Somewhat later, devices such as a windshield, a cockpit fairing and instruments appeared.
modern gliders. When designing a glider, it is necessary to meet the conflicting requirements for achieving high flight performance, guaranteed strength and low cost. Gliders are made from metals, wood, fabrics, fiberglass, and combinations thereof. Soaring gliders, which must have the highest aerodynamic efficiency, use fiberglass and, in some cases, balsa wood. Such an extremely strong and lightweight composite makes it possible to design soarers with a relative glide range of 40 (40 m forward movement per 1 m height loss) and more. The higher the planned characteristics of the airframe, the more streamlined its fuselage and cockpit should be, and the greater the elongation of its wing and tail surfaces. Virtually all soaring gliders that have achieved record results are masterpieces with the perfect combination of aerodynamics and structural strength. The controls of such aircraft must provide ease of control and high maneuverability.
Capacity. There are single and multi-seat gliders and soarers. Two-seat gliders are used for training purposes and for flights in the airfield area. The pilot and his companion are placed one behind the other or side by side. In the latter case, communication and monitoring of devices is simplified. Three- and four-seater gliders were also built. During the Second World War, even more capacious transport gliders were developed and used, capable of delivering ten (or more) fully armed soldiers or a load of the appropriate weight to enemy territory.
Unmanned gliders. Unmanned gliders found use during the Second World War in the form of glide bombs dropped from aircraft on land or sea targets. In a number of cases, remote radio guidance was carried out at the target using television or direct visual aiming. In other cases, homing or programmable autopilots have been used. Gliders were also built and tested in flight, which were experimental models of larger aircraft with power plants. Such gliders are intended for the study of flight performance in the absence of perturbations created by thrust. power plant, at a significantly lower cost or emergency risk of flight tests, which is especially important in cases of testing non-traditional layouts, as well as at unusual flight speeds or altitudes.
Wings. Some of the most important aerodynamic innovations in aircraft design are often tested first in gliders. As an example, we can mention the experimental verification of the high efficiency of a high aspect ratio wing (i.e., a wing with a large value of the ratio of the wing span to its chord). Another example is the establishment of the desirability of maintaining a smooth (laminar) air flow around the surface of the wing. Through experiments with gliders, it has been found that cantilever monoplane wings have higher aerodynamic and strength characteristics than braced or polyplane wings. The glider designs used various wing-fuselage layouts, such as low-wing, medium-wing, high-wing and parasol (a monoplane with a wing over the fuselage), as well as many layout schemes, including a "duck". The highest record achievements belong to the monoplanes of the traditional scheme with a medium or high wing and tail. A high-lift wing typically has a single spar to absorb bending forces and a D-toe to absorb torque; it is reinforced with several ribs that protect the wing surface from warping. The wings, made from aircraft plywood, have been brought to a high degree of aerodynamic perfection. Later, a light and strong all-metal airframe wing structure was created, but fabric covering of the wing section behind the supporting spar is usually considered more preferable. The controls of gliders, such as rudders, elevators and ailerons, are practically the same as on light motor aircraft, except that the rudders and ailerons are enlarged to match the larger wingspan of the glider. The V-tail, which performs the functions of elevators and rudders, was successfully used on soaring gliders. Some gliders use landing flaps, but spoilers are more common, mounted only on the upper surface or on both surfaces of the tapering part of the wing. The spoilers act as an air brake, which interrupts the smooth flow of air near the wing surface in order to increase the rate of descent during landing or for a sharp decrease in altitude.
Control system. The rudder control of the airframe is usually carried out using pedals (foot control), and the control of the elevator and ailerons - using the control stick (manual control), however, in some cases, other, less traditional ways. Control commands are transmitted to the steering surfaces using cables, rods or tubular shafts. Some gliders are loaded with water ballast to improve flight performance and are equipped with flaps that allow you to change the profile and wing area during flight (the ballast is drained before landing). Many inventions have been associated with the development of improved high-speed connecting fittings and connectors in control systems, as well as wing and tail designs.
Fuselage and landing gear. Fuselage designs are very diverse and vary from box-type to sophisticated well-streamlined shapes. Some utility gliders are equipped with a conventional two-wheel landing gear, but most soaring gliders have only one wheel, which is located near the center of gravity under the fuselage. The wingtip edgings allow the glider to rest one wing on the ground after it has come to a stop under the action of the braking device on the wheel and has landed on the nose or skid at the front of the fuselage. The central wheel can be partially retractable. Record-breaking gliders, equipped with only a landing ski, are usually placed on a drop auxiliary cart, with which the takeoff is carried out.
Devices. In addition to the usual aircraft instruments, such as the altimeter, airspeed indicator, direction and slip indicators and compass, which are usually supplied with all gliders, as well as radio communication systems, which are equipped with some gliders, some special instruments have been developed. This, for example, is a highly sensitive vertical speed meter (variometer) and a barograph that registers flight altitude. Analyzers of small temperature differences were also tested in flight. Such analyzers are a set of on-board instruments that allow the pilot to determine the temperature difference (if any) at the ends of the wings. Using these readings, the pilot can detect rising currents of heated air and use them to climb. High-altitude soaring gliders are equipped with oxygen-respiratory systems. On military gliders, devices are installed to facilitate towing in conditions of lack of visibility (at night or in clouds). Means were also created for the rapid landing and disembarkation of troops, the loading and unloading of artillery, Vehicle and other cargo.
Takeoff. Special methods for operating gliders have been developed. The dismantled glider is transported over the ground on a special trailer. Glider takeoff can be done in different ways. On a flat and level ground, the glider can quickly climb from 150 to 600 m when towed by a car or a pull winch. Then the pilot is released from the towline by opening the mechanical lock on the tow hook. On short runways, the towing vehicle may be equipped with a system of pulleys through which the tow rope is passed, which allows the glider to be towed at a speed significantly higher than the speed of the vehicle. Gliders on floats or with a fuselage-boat can take off from the surface of the reservoir, but for this you need to have a sufficiently powerful tugboat.
Flight in tow. IN Lately takeoff of a glider is carried out, as a rule, by towing it by a light single-engine aircraft. Usually one glider is towed, but two, three or four gliders are also towed for display at exhibitions, flights over long distances or for military purposes. Flights over long distances can be carried out by gliders both over land and over water. For towing lines, hemp ropes, steel ropes, cables or nylon ropes are used. The length of the towing halyard is 50-150 m. The pilot of the towed glider prefers to fly a little higher or a little lower than the towing aircraft, so as not to fall into its turbulent wake, and maintain a constant cable tension. When turning, the pilot follows the leader, repeating his maneuvers. The towing rope is attached to the tail section of the aircraft, taking into account the safety requirements from the loads that occur during towing. The glider pilot can unfasten his end of the cable if he wants to continue flying on his own.
Motor gliders. Some gliders are equipped with a small auxiliary engine that they use to take off on their own. The auxiliary engine can serve not only for take-off, but also for flying through an area with adverse atmospheric conditions, as well as in emergency situations. After takeoff, the engine is turned off, and on some gliders it is removed inside the fuselage. On other gliders with an engine located inside the fuselage, the propeller "feathers" to reduce air resistance. The engine can also be turned on in the final section so that the glider can fly to the airfield. In general, glider engines consume very little fuel. Typically, propeller engines are used on gliders, but experimental flights have been carried out using a rocket engine.
Soaring. An early form of gliding was gliding from the top of a mountain into a valley. In this glide in still air, the glider loses altitude at a rate that is in the same proportion to the horizontal flight speed as the ratio of drag force to lift. In contrast to glide down, soaring is the art of maintaining or even gaining altitude without engine power through the skillful use of wind power and updrafts. There are a number of methods for using the wind to soar, of which soaring over a mountainside is the simplest. Updrafts of air over a mountain slope or a steep bank can keep a glider in the air for a long time if its rate of descent in calm air is comparable to the rate of rise of air masses. (Birds hovering is explained by this effect.) A hovering glider can be directed into the wind; it can also zigzag along a windward slope, covering long distances in the process. Updrafts can extend up to several times the height of the obstruction and start quite far from the windward slope. Updrafts of air often occur in the atmosphere. They appear, for example, during uneven heating of the earth's surface (thermals, or thermal currents). In such a flow, a soaring glider or bird can describe circles and spirals without losing or even gaining altitude. If the rising air is moist, then clouds form in it. A typical sign of an ascending thermal current is cumulus clouds over flat terrain. Powerful updrafts of air occur at the front of a hurricane or thunderstorm. These currents are sometimes used to lift gliders to high altitudes and fly long distances. However, such flights are extremely risky due to severe turbulence, ice formation and hail that usually accompany a storm or thunderstorm. At high altitudes, especially over the lee side of a mountain, the wind can create huge circulation zones in which updrafts are sometimes detected by characteristic lenticular clouds bulging above and below. Some of these clouds line up in a regular line, inviting an experienced glider to take a walk on the air waves.
Glider "Nimbus-3" IN FLIGHT.
Flying a glider over rough terrain is the most difficult gliding sport. When flying over a distance or flying to a designated place, the glider pilot uses in flight all the air currents that are useful for him that are encountered on the way: winds that arise over the slopes of mountains, thermals due to terrain or atmospheric instability, cloud paths, frontal surfaces and wind waves. Sometimes the pilot soars, moving back and forth until he encounters a cloud-topped thermal that extends along his path and allows him to gain altitude. He can use this flow to climb to high altitude and then glide down to meet the next thermal. It happens (especially late in the evening) that when a pilot considers an unplanned landing due to a loss of altitude already inevitable, he will suddenly encounter a thermal near the ground, which will again raise the glider to a height. A spectacular flight of this kind requires not only high piloting skills, but also navigational skills and a deep understanding of meteorological phenomena. Currently, glider pilots reach altitudes of the order of 18 km using pressurized cabins or high-altitude space suits.
Hang gliding. Very light aircraft, similar to a kite, on which a person can take off and land on his own, without the use of any additional means and devices, have become widespread. On such a glider, heights of more than 3.5 km were reached. The pilot, hanging on a harness, controls the hang glider by moving his body, as did the first pilots.
Research work. Soaring gliders are successfully used to study meteorological phenomena. Due to the absence of vibrations from the power plant, these aircraft are ideal platforms for mounting meteorological instruments on them. The use of gliders to study aerodynamic problems has been mentioned above.
Maneuvers. Almost all aerobatics performed by motorized aircraft were performed on non-powered gliders. These are loops, barrels, flight in an inverted position, a corkscrew; they are all constituent parts a set of figures demonstrated in demonstration flights by glider pilots. Gliders with spoilers can land on a wheel or central ski with high landing accuracy on small areas. In precision landing competitions, the winners usually land within 30 cm of the glider from the control flag. The accuracy of flying a glider requires good training and a lot of practice.
Education. For pilot training, a two-seat glider is used, in which the instructor sits with the student and explains to him all the actions performed during towing, free flight and landing, including exit from emergencies. He also observes the student's behavior and corrects his mistakes. Practical experience, acquired by a glider pilot, is a guarantee of success in learning the art of piloting an aircraft and a prerequisite for excellence in any other field of aviation.
Competitions. There are international, national, regional and local competitions in gliding. The first glider competitions took place in Germany in 1920. The first All-Union glider tests (competitions) were held in 1923 in Koktebel. The first World Gliding Championship was held in Germany in 1937.
see also
A diary is a great tool for planning your schedule and daily activities. And you can add a lot of useful things to your diary that will help you remember the main thing, be organized in all areas of life, and most importantly, unload your head. After all, in fact, there are a lot of things that we try to remember and keep in our heads, although it would be better to write them down and free up the space of our memory 😉
Below are 33 ideas for your diary to make it even more useful.
Health and sports
- Drinking mode. We all know that you need to drink about 1.5-2 liters during the day. clean water. And in order not to forget about some water in the #So_easy_planner diary there is such a daily tracker. It's simple: I drank a glass - painted over it. You will never forget that you need to drink water, because. it's right before your eyes, and you won't forget how much you've already drunk 😉
- Physical exercise. You can borrow daily or according to some weekly schedule. You just need to write it in the window of daily activities and habits in your notebook. For example, note that I go to yoga on Mon, Wed and Fri. And also, for example, I run every day, we also write a run here and mark it every day. Everything is in front of your eyes, pretend that you forgot to fail 😉
- Sports programs. If, for example, you are engaged in some kind of program, or doing a challenge, then they can also be painted on pages for writing or simply printed and pasted or attached with a paper clip to a diary. By the way, a cool site with such programs and challenges darebee.com. For example, do you want to learn how to hold the bar for 5 minutes in a month? Please!
- Nutrition programs or challenges. For example, you pass detox program? Do you want to rid your body of sugar? etc.
family and home
Personal
Business and technology
Children
- Schedule of extra classes. We have two daughters. The eldest is engaged in cheerleading, drawing and English, the youngest goes to school preparation and will soon go to black too. It happens that a grandmother calls and says: I will pick up my granddaughter after training, at what time is she free? And I just have a stupor, I don’t remember right away. Of course, you can keep all these training schedules in your head, but why;). You can just write it down.
- School timetable. If needed, of course. For example, I do not follow this 😉
- School bell schedule. But this is a necessary thing to understand when you can call the child if suddenly something happens, and when it is not necessary.
- Vacation schedule. It is usually said at the beginning of the school year and it is useful to write it down to plan family time, vacations, vacations.
Finance
- Savings tracker. If you want to save up a certain amount of money for a large purchase or just for a vacation and want to see the progress visually, such a tracker will be very convenient.
- credit tracker. Again, if there are loans and you want to visually observe how much is left until full repayment.
- Bill payment dates. Of course, if it is necessary and important. For example, my meals in the garden are paid until the 20th of the current month, and for English and preparation for school you need to pay until the 1st. Etc.
What interesting things do you keep track of or write down in your diary? Share with us in the comments below 😉
Incoming air flow. A glider or glider is also called the supporting structure of an aircraft.
Aeronautics professionals generally share the terms:
- glider- directly aircraftcapable of flying, or rather, planning; - glider- the supporting structure of the aircraft (that is, the supporting structure of the glider can be said: glider glider).
To deliver the glider to the starting point of free flight, either an aircraft of a different type (usually an airplane) or a special ground glider winch is used. A rubber band pulled by a group of people can be used, as well as starting from the windward side of a mountain. In history, such exotic methods were also used, such as their own engine with a small resource (for example, a solid propellant rocket engine), or a catapult.
There are also gliders with their own internal combustion engine and propeller. Most motor gliders use the engine only after takeoff (to climb in flight, the so-called cruising motor gliders), but some of their models with sufficient engine thrust are able to take off on their own.
Emmanuel Swedenborg (1688-1772) made sketches of a glider around 1714. In 1853, Sir George Cayley designed the first modern glider to lift a man into the air.
At the turn of the XIX-XX centuries, the most famous creator of gliders was Otto Lilienthal. Having made and tested many models, he created a successful design of a balanced glider with good flight characteristics. The heyday of gliders came in the 1920s and 1930s, when a real boom in gliding schools began. In the USSR, it even happened in the provinces (see, for example, the Liven Gliding Flight School). Many WWII pilots made their first flights at these schools. Availability and relative cheapness contributed to the widespread use of gliding after the end of the war.
Currently, gliding is a universally recognized and mass hobby in developed countries. Modern gliders, thanks to the achievements of aerodynamics and materials science, are able to fly 60 km in a straight line from a height of 1 km in calm air. Experienced glider pilots, using updrafts - thermals, are able to overcome hundreds of kilometers. There are also gliders for aerobatics and flights behind a thunderstorm front, which allows you to use powerful updrafts and fly considerable distances.
According to the rules of the International Aviation Federation, records in gliding are recorded if they are set within one daylight hours. The maximum distance covered by the glider is 3009 km. Klaus Olman ( Klaus Ohlmann) from Germany performed this flight on January 21, 2003.
Modern gliders are very diverse: starting from ultralight ones, weighing ten kilograms and flying at a speed slightly higher than the speed of a horse, and ending with space shuttles, with a starting mass of more than 100 tons and an orbital speed of 28 thousand km / h - any winged spacecraft descends in the atmosphere and lands in glider mode, although its flight characteristics bear little resemblance to an ordinary glider.
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Notes
Links
- Dvoenosov D., Zamyatin V., Sneshko O. Tutorial. M .: DOSAAF, 1963 (PDF , 1.9 MB)
- Goncharenko V.V.
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An excerpt characterizing the Glider
For a few seconds they both looked with frightened eyes at the faces alien to each other, and both were at a loss about what they had done and what they should do. “Am I taken prisoner, or is he taken prisoner by me? thought each of them. But, obviously, the French officer was more inclined to think that he had been taken prisoner, because Pierre's strong hand, driven by involuntary fear, squeezed his throat tighter and tighter. The Frenchman was about to say something, when suddenly a cannonball whistled low and terribly over their heads, and it seemed to Pierre that the head of the French officer had been torn off: he bent it so quickly.Pierre also bent his head and let go of his hands. No longer thinking about who captured whom, the Frenchman ran back to the battery, and Pierre downhill, stumbling over the dead and wounded, who, it seemed to him, were catching him by the legs. But before he had time to go down, dense crowds of fleeing Russian soldiers appeared to meet him, who, falling, stumbling and shouting, merrily and violently ran towards the battery. (This was the attack that Yermolov attributed to himself, saying that only his courage and happiness could accomplish this feat, and the attack in which he allegedly threw the St. George Crosses that he had in his pocket onto the mound.)
The French, who occupied the battery, ran. Our troops, shouting "Hurrah," drove the French so far behind the battery that it was difficult to stop them.
Prisoners were taken from the battery, including a wounded French general, who was surrounded by officers. Crowds of the wounded, familiar and unfamiliar to Pierre, Russians and French, with faces disfigured by suffering, walked, crawled and rushed from the battery on a stretcher. Pierre entered the mound, where he spent more than an hour, and from that family circle that took him in, he did not find anyone. There were many dead here, unknown to him. But he recognized some. A young officer sat, still curled up, at the edge of the rampart, in a pool of blood. The red-faced soldier was still twitching, but he was not removed.
Pierre ran downstairs.
"No, now they will leave it, now they will be horrified at what they have done!" thought Pierre, aimlessly following the crowds of stretchers moving from the battlefield.
But the sun, covered with smoke, was still high, and ahead, and especially to the left of Semenovsky, something was seething in the smoke, and the rumble of shots, shooting and cannonade, not only did not weaken, but intensified to the point of desperation, like a man who, overstrained, screams with all his might.
The main action of the Battle of Borodino took place in the space of a thousand sazhens between Borodino and the fleches of Bagration. (Outside this space, on the one hand, a demonstration by Uvarov's cavalry was made by the Russians in the middle of the day, on the other hand, beyond Utitsa, there was a clash between Poniatowski and Tuchkov; but these were two separate and weak actions compared to what happened in the middle of the battlefield. ) On the field between Borodin and the flushes, near the forest, in an open and visible stretch from both sides, the main action of the battle took place, in the simplest, most unsophisticated way.
The battle began with a cannonade from both sides from several hundred guns.
Then, when the whole field was covered with smoke, in this smoke (from the side of the French) two divisions, Desse and Compana, moved on the right to the flushes, and on the left the regiments of the Viceroy to Borodino.
From the Shevardinsky redoubt, on which Napoleon stood, the fleches were at a distance of a verst, and Borodino was more than two versts in a straight line, and therefore Napoleon could not see what was happening there, especially since the smoke, merging with the fog, hid all terrain. The soldiers of the Desse division, directed at the fleches, were visible only until they descended under the ravine that separated them from the fleches. As soon as they descended into the ravine, the smoke of gun and rifle shots on the flashes became so thick that it covered the entire rise on that side of the ravine. Something black flickered through the smoke - probably people, and sometimes the gleam of bayonets. But whether they were moving or standing, whether they were French or Russian, it was impossible to see from the Shevardinsky redoubt.
The sun rose brightly and beat with slanting rays right in the face of Napoleon, who looked from under his arm at the flushes. Smoke crept in front of the flushes, and now it seemed that the smoke was moving, now it seemed that the troops were moving. From behind the shots, the cries of people were sometimes heard, but it was impossible to know what they were doing there.
Napoleon, standing on the mound, looked into the chimney, and in the small circle of the chimney he saw smoke and people, sometimes his own, sometimes Russians; but where it was that he saw, he did not know when he looked again with a simple eye.
He descended from the mound and began to walk up and down in front of it.
Occasionally he stopped, listened to the shots and peered into the battlefield.
Not only from the place below where he stood, not only from the mound on which some of his generals now stood, but also from the very fleches, on which were now together and alternately now Russians, now French, dead, wounded and alive, frightened or distraught soldiers, it was impossible to understand what was happening in this place. In the course of several hours, in this place, amidst the incessant shooting, rifle and cannon, either Russians, or French, or infantry, or cavalry soldiers appeared; appeared, fell, shot, collided, not knowing what to do with each other, shouted and ran back.
Gliders soaring in the sky are kept on the same lift, which allows ordinary aircraft to fly. In a powerful free flight, the lift force of a glider is generated on its wings in exactly the same way as in an airplane, that is, with the help of engine thrust.
Another main force that creates forward thrust for a glider is its gravity. The movement of the glider forward at first, on takeoff, is provided by the towing means and the pulling action of two forces: gravity and ascending air currents. And then fast air flight provides lift as the air flows around the wings above and below.
The slender soaring glider has a narrow fuselage and long wings, allowing it to obtain more lift than aircraft equipped with a powerful engine.
High in the sky, on the air currents that create lift, an eagle soars with its wings outstretched.
The principle of soaring
A glider pilot must balance three forces: gravity, lift, and air resistance.
Spoiler assignment
In flight, the glider keeps the optimal angle with respect to the earth's surface. For landing, the spoilers located on the wings of the glider are raised. At the same time, air resistance increases, speed drops and the glide angle changes accordingly.
Glider takeoff
The glider can be towed into the sky using a car or with a powerful winch standing on the ground.
The glider can also be launched upwards with the help of an aircraft tug, which then unhooks the rope, leaving the glider in free flight.
Soaring on air currents
The pilot can greatly increase the time the glider is in the air if he skillfully uses the prevailing air currents.
Mountain updrafts give remarkable lift when strong winds meet there and blow up the slope.
Winds, hitting the top of the mountain, form updrafts over the reverse slope.
Thermals, or currents of air rising from the earth heated by the sun, can carry a glider to great heights.
The glider sets spoilers to set the desired speed.
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