Sail wing. Inflated wing sails: advantages of new technology. The concept of a chord modified by a sail

Wing sail! The theme, of course, is very original. But somewhere in the “background” one feels a certain inferiority complex of “born to crawl”, but passionately wanting to fly. A person with such a complex, as it were, elevates the status of a sail, such a wretched, nondescript and primitive device, to the sparkling heavenly heights of a miracle of evolution - a wing.
So that there is no mishmash of flies and cutlets, before starting such topics, it would be good to decide for yourself, what will we do? How is a wing different from a sail? In my opinion, because wings were invented for free flight in the air, and sails were invented for moving along the boundary between air and water. And then it is completely unclear why the hell it is to call one another, or to mix these two different terms into one heap. A sail, as an idea, is no worse or better than a wing, as an idea; it is simply intended to perform a completely different function than a wing. That is, as an idea, the sail does not need any “qualitative” improvements or upgrades to something more perfect, since there is simply nothing more perfect to perform the function for which it is intended. Well, it’s stupid to try to move up when we need to move forward, these are different directions of movement.
The second motivating reason for playing with words, in addition to the complex of a failed pilot, is usually technical illiteracy: they say, a sail is such a rag tied to a stick with ropes, and a wing is so long, thick and smooth, like... the sides of an airplane, in short. If you take a little interest in the question, it becomes clear that this reason is completely groundless: the wings of the first airplanes (and even the last ones) were no thicker than “a rag on a stick with ropes.” That is, the volume of the “bearing surface” (both the wing and the sail fit equally well under this definition) is not fundamental for the carrying surface to fulfill its function: to create a large transverse (to the direction of the speed of the flow flowing around it) force while the longitudinal force is small. Volumetric sails were created several times, including for windsurfing, but they never showed any convincing advantages of volumetricity, and therefore were quickly forgotten. Well, another “reinvention of the wheel.” Pached? Respect? Why? Most likely, the man simply believes in one of the myths from the “modern wing theory”, and with tenacity worthy of better use, spends his time and money to prove it, of course - unsuccessfully. If his livelihood depended only on income from the sale of his “miracle sails,” then his persistence would quickly fade away, but as a hobby - why not, life would be boring without eccentrics.

High-speed environmentally friendly transport

The absolute world speed record on water for a sailing vessel is 46.52 knots (86.16 km/h), and the speed of the record holder, the three-point vehicle Yellow Pages Endeavour, was more than twice as high as the wind speed (20 knots).
The world iceboat speed record is much higher - 230.1 km/h. It was installed 60 years ago on one of the North American lakes. On a wheeled (beach) yacht, the speed record exceeds 160 km/h. As you can see, the minimum resistance of the skates and the absence of drift provide maximum speed for the sailboat moving on the ice.
Conditions are most unfavorable for sailing on water. Firstly, this is a high hydrodynamic resistance, which increases sharply with increasing speed. Secondly, in order to develop high speed, a very strong wind is needed, and the stronger it is, the higher the waves, which increase the resistance of the water to the movement of the yacht. Thirdly, as the wind increases, an increasingly significant amount of resistance is added by the list and especially the yacht’s drift downwind. If you don’t prevent the growth of roll and drift, you won’t set the sails to maximum thrust, and there will be no speed.
So you have to use all sorts of tricks to increase speed on the water. And as a result, the same current world record holder, the three-point "Yellow Pages Endeavor" (see "KiYa" No. 159), practically no longer resembles a traditional keel yacht, the ways of improving which have already been largely exhausted.
It is characteristic that before the ELE, for six years the world speed record on water under sail was held by a sailing board, which also had very little in common with a classic yacht. With a sail area of ​​only 4 m2, such a planing sailboat has minimal displacement and, therefore, minimal hydrodynamic resistance. The yachtsman counters both the drift and the roll of the board with his own weight, which is much greater than the weight of the windsurfer, and with the hydrodynamic force generated on the centerboard. Combining this with control that ensures the highest efficiency of the sail in sufficiently strong winds is very difficult, not to mention the fact that just holding the sail in your hands requires enormous effort. One thing is good: apart from acceleration, the movement itself along a measured 500-meter track takes less than half a minute...
Of course, you can’t go against even a not very high wave on a small planing board. Races to break the record are carried out only on narrow channels, on the limited surface of which waves do not have time to develop even with a wind of 20 m/s.

Drawing from the “Description of the invention to the Copyright Certificate 8 and 1699860 A 1 - Windg-leider”. Author - Yu. V. Makarov. The embodiment of the idea of ​​combining a windsurfer and hang glider, a - plan; 6 - side view during acceleration on port tack", in- front view during steady movement.

But here's what's interesting. Professional windsurfers who compete in "wave" competitions - on a breaking wave - do not chase the speed of movement, but with a sail in their hands they demonstrate the wonders of acrobatics.
For example, having accelerated, the yachtsman sets the sail horizontally into the wind and, taking off 2-3 m, continues the flight for 8-10 seconds, while holding on to the boom, like the trapeze of a hang glider. The uncontrolled flight ends with the windsurfer falling backwards into the water. This is not surprising. The flight is unstable, the aerodynamic quality of this version of the “aircraft” does not exceed 1.5-2.0.
The sight of a sailboard during such a sailing flight is a “friendly cartoon” of a hang glider. And indeed. We see the same wing-sail, only with half the area, and instead of a trapezoid across the wing span of a hang glider there is a sail boom. However, on a sailboard you won’t fly much (balance control is not provided), and on a hang glider you won’t be able to accelerate using wind energy. Try to manipulate the wing of a hang glider relative to the wind with a wing span of 10 m and a weight of more than 30 kg!
And here a question involuntarily arises. What if you combine these two devices into a single design to expand their range of applications?
During the design process, it was actually possible to optimize the design of the hang glider so that it could be used as a windsurfer's wing-sail.
The ideal sail is a soaring glider, which has been successfully used in sports aviation for a long time. Using it, you can create a number of interesting sailboats. The results of this work were reported back in 1979 at the I All-Union Scientific and Technical Symposium “Research, design and construction of modern sailing ships.” Firstly, a multi-purpose hang glider was designed with a new layout. This is a rigid composite wing, the center section of which has a low aspect ratio and an arched trailing edge, and the consoles are docked at an angle of 30° to the center section and connected by a strut, which serves as a control trapezoid.
Such a hang glider can be used in the traditional version, i.e. for flights from slopes, as a trike, but also as a sail with increased aerodynamic quality for a catamaran windsurfer or light iceboat. A hang glider on roller skates can travel at high speed, for example, along the runway in any direction, changing tack. In winter, on skates on good ice, he can reach speeds of more than 160 km/h. You can also move on skis, and the possibilities for choosing a site for flying with the help of the wind will be much wider, especially in the northern regions of the country.
The advantage of this multifunctional hang glider is that it can be used for takeoff using wind power.
It happens like this. A hang glider on skates or skis sets the wing-sail (i.e., hang glider) vertically - at an angle to the wind and begins acceleration. As the speed increases, it turns the wing into the true wind and reaches a speed of 80-130 km/h (depending on the conditions of the runway - asphalt, ice, dense snow). Now he sets the wing horizontally and, increasing its angle of attack, smoothly gains a height of 20-30 m and makes a gliding flight. Of course, the flight in this case is significantly different from a short-term flight on a windsurfer's sail. Here, a given position of the center of gravity relative to the wing chord is ensured (which ensures flight stability) and, most importantly, there is a classic balancing control system with a steering linkage. The climb is carried out due to the high speed gained before take-off. If we take into account that the minimum (landing) flight speed of a hang glider is 3bkm/h (with a wing load of about 10 kg/m2), and the speed at the moment of takeoff is 80-130 km/h, i.e. two to three times higher, then the hang glider can continue to climb until the speed drops to 40-45 km/h. The achieved height of 30 m will be the dynamic ceiling of the hang glider for these flight conditions.
It is interesting to note that the pre-war I-16 fighter, after accelerating in horizontal flight near the ground, having reached its maximum speed (400 km/h), could jump vertically to a height of 700 m, performing an upward spin. And the famous pilot B.K. Podoshva on the A-13 aerobatic glider at the air parade in Tushino passed over the entire field with his head to the ground at an altitude of 3 m at a speed of 360 km/h, and then went vertically to a height of 400 m.
Of course, a hang glider-sailboat does not require such speeds and dynamic ceilings. He needs a speed of about 150 km/h, space and flight at an altitude of 1.5-2 m with high aerodynamic efficiency in light winds (some 5-6 m/sec).
And such an exotic flight over water is no longer a fantasy, but a reality, quite achievable for an ekranoplane with sails. The sailing armament of the ekranoplan is a Y-shaped “swinging” rigid wing with an area of ​​6 m2 and a span of 8 m, mounted on the top of a short mast. A ring boom is used to control the rotation of the wing, and a handle with a rod is used to change the tack.

The body of the ekranoplan is made in the form of a low aspect ratio wing with two end floats on which centerboards are installed. The third - central, pivoting centerboard is located on the trailing edge of the wing under the vertical tail with an air rudder. (For a land or ice ekranoplan, wheels or skates are installed instead of floats and centerboards).
Having accelerated, the sailing ekranolet maintains contact with the water only with the end sections of the three centerboards and flies using the screen effect. A short approach of an ekranoplan does not foreshadow an emergency situation, since the device has an aerodynamic control system.

Single-seat ekranoplane with a V-shaped "swinging" rigid wing

In this case, the ekranoplane makes a gliding flight over the screen, but the loss of contact with the water leads to the disappearance of sail thrust and the ekranoplane, descending, again comes into contact with the water with its centerboards. Thus, the yachtsman periodically is either in free gliding above the surface of the water, or in contact with the water, which resumes the thrust of the sail.
The speed of the sailing ekranoplan is 90-120 km/h with a wind speed of only 5-8 m/sec; in other words, the movement speed is three to four times higher than the wind speed, and not two and a half, like the EPE. On the highway, a sailing ekranoplan - iceboat accelerates to a speed of 140-160 km/h.
The sails and winged sailboats discussed above have a small, by aviation standards, aerodynamic quality - about 10-15 (well, let's say 20 - using the screen effect). And we have an achievable sail aerodynamic quality of at least 40-45! And such optimism has practical confirmation: modern open-class soaring gliders have an aerodynamic quality of 63-65!
A rigid aerodynamic sail such as a glider wing is often used on high-speed sailboats, but only one (left or right) console is used. With such a sail you can only sail on one tack, because they use an asymmetrical wing profile to obtain maximum thrust. To tilt, it is necessary to use counterweights - such as a cockpit positioned to the wind; a complex sail-wing control system is required.

WIG diagram

b - general view of the catamaran with a “swinging” glider - sail. 1- serial two-seat glider mounted on a 12-joint; 7 - “vertical” wing of the glider, serving as a highly efficient sail - wing; 8 -~ support float with a rotating keel; 9 - “horizontal” tilting wing of the glider providing aerodynamic unloading; 12 - hinge; 13 - catamaran hull; 14 - steering wheel; 15- V-shaped controlled centerboard, in - central unit device - universal

A record sailing ship, if the design of a standard glider is used as its sailing system, turns out to be primitively simple, light and durable, with excellent stability and controllability of the sailing system, and with enormous aerodynamic quality.

Of course, it will have to be slightly modified - add a wing support, change the angle of the transverse Y-shape of the wing and install a universal joint for attaching the airframe to the top of the “mast”.
A light sailboat, designed for record-breaking races, is a catamaran with planing hulls, on the short mast of which a two-seat glider-sail is installed on a universal (universal) joint. In this case, the hinge is located in the center of gravity of the glider. The cockpit contains a steering wheel for controlling the course of the air rudder. The airframe control system remains unchanged, but is now a weapons control system.
When changing tack, the wings are “shifted” using ailerons: the wing that served as a sail becomes horizontal - heeling (with a support float and a controlled keel (centerboard) at the end), and which was heeling - becomes almost vertical and works as a highly efficient rigid sail of high elongation.
The acceleration and movement of a sailboat is carried out by setting the sails relative to the wind using the glider's aerodynamic rudders (ailerons, elevators and rudder) and the yacht's rudders. Since the glider has the necessary stability and a perfect control system designed for aerobatics (and even more so for free flight!), no problems arise in controlling the sailboat.
In the event of a takeoff (short-term takeoff), the glider can calmly escape from the elements “alien” to it, unlike a classic racing sailboat, when lifting off the water ends in an accident.
The thrust force of the glider wings is directed forward and upward, which significantly reduces the roll moment, and the lifting force of the horizontal wing provides aerodynamic unloading of the yacht. Aerodynamic unloading can be up to 80-100% of the weight. The sailboat in this mode touches the water only with its centerboards, and with a reserve of horizontal speed it can even make gliding flights over the water; in this case, both wings are installed symmetrically relative to the water surface, and the floats (or buoy landing gear) are fixed along the longitudinal axis of the airframe.
The sailboat for breaking world speed records, made using the serial two-seater glider 1--13 "V!atK" (with aerodynamic quality 28), has the following technical data. Maximum weight with two yachtsmen on board is 550 kg. The area of ​​the vertical wing-sail is 10 m2 (the total area of ​​the wings is 20 mg). The maximum aerodynamic quality in the catamaran yacht version is 10, in the boat version -18.
Calculations show that a sailing ship develops its maximum speed in a gulfwind wind, which blows at an angle of 90° relative to the direction of movement. For an ideal sailboat (in the absence of drift, heel and hydrodynamic drag), the speed of the ship - V would be equal to the wind speed V multiplied by the aerodynamic quality of the sail:
y=KU.
Take a closer look at this expression. Yes, this is the formula for determining the horizontal speed of a glider! And truly, the ideal yacht is a glider. And the glider is an ideal sailboat. Its main characteristic is aerodynamic quality. After all, it has no drift, roll or hydrodynamic resistance. And it flies without descending under the influence of rising currents (vertical wind). If there are no rising currents, the glider always has an “artificial wind” for flight, and it always blows into the gulfwind: this is the vertical speed of its descent - Vв. In this case, the horizontal flight speed - Vg is determined as follows:
Vg=KVv.

1 - thrust force, 2 - total aerodynamic force, 3 - drift force

As you can see, both expressions are identical. Here K is the same aerodynamic quality of the glider. It is not for nothing that in many languages ​​the words “glider” and “sailboat” sound the same.
And now the ideal yacht is compatible with a real sailboat. To do this, the glider must be installed on the mast so that its wings (sails) are in a vertical position. Then, with a wind of only 2 m/s and no drift (otherwise the force of the wind will disappear), we can get the maximum speed of our yacht at K = 50 equal to:
2 m/s x 50 = 100 m/s or 360 km/h
those. 50 times the wind speed. This is how gliders fly. But we need to devote part of the energy to fighting drift, and another part to overcoming roll and hydrodynamic resistance. In reality, we have about 8 units left: Kx - 8, where Kx is the performance of the yacht. Therefore, the maximum and absolutely real speed of the yacht in a wind of 5 m/s will be equal to:
5 m/s x 8 = 40 m/s (144 km/h), i.e. exceeds the wind speed by eight times (we remind you once again: for “EPE” it is more than two times). As you can see, the sail plays the role of an aerodynamic “amplifier” of the wind.
Now let's summarize the preliminary results. What do we have in our assets? We can set two world records and receive a prize of 3 million dollars with the help of a record-breaking yacht - a glider-sailboat.
The world iceboat speed record (230.1 km/h) can be increased to 280 km/h with a wind speed of 5 m/s; this requires Kx - the sailing quality of the ice boat, equal to only 16. Well, the existing speed record of a sailing yacht will be broken with the same wind even at Kx = 6, which will ensure a sailing speed of 30 m/s, i.e. 108 km/h. Today's speed record is 86.16 km/h, but with a wind of 10 m/s!
Competitions to set world speed records under sail are held in Weymouth (England) annually. Those interested should hurry!
So far we have been talking about sports sailboats that demonstrate the boundaries of possible achievements - record results. For transport purposes on maritime cargo and passenger lines, environmentally friendly high-speed vessels with minimal fuel consumption, simple and reliable in operation are needed.
The sailing ekranoplan designed at MAI, designed for 40 passenger seats, can serve as an example of such an environmentally friendly and high-speed sea express. Its speed with a wind of 5-8 m/s will be about 90-110 km/h. The maximum weight of the winged sailboat is 5800 kg, the weight of the structure is 1800 kg.
The route New York - Cape Lizard (England) can be completed on this sailboat in just three days, while the record-breaking trimaran Jet Services 5 took twice as long.

Environmentally friendly transport.

It is known that the French chocolate company Poulet announced a reward of $1 million. the first solo yachtsman to sail around the globe in 100 days, and the current winners of the Jules Verne Trophy have already circumnavigated the world - crossed all the meridians and the equator - in 71 days. But for a sailing ekranoplan of the proposed design, 25 days of “around the world” (even when sailing alone) will be the duration of the regular voyage indicated in the schedule. After all, the ekranoplan-sailboat is not intended for records, but for passenger flights. For example, for shuttle flights across the Black Sea. Forty passengers from Odessa will be in Yalta in 5 hours, and in Istanbul in 8, and the team will spend a maximum of 10 kg of diesel fuel on approaches to the berth in the specified ports.
The only way to travel “cheaper” and with less impact on the environment is by drifting on an ice floe! Using the energy of the air ocean, we do not pollute the atmosphere with oxides of carbon, nitrogen and hydrocarbons, and most importantly, we do not throw money down the drain by burning energy resources. One refueling of a large-capacity ocean vessel costs 1.5-5 million dollars. A vessel with a displacement of 20 thousand tons at a speed of 16 knots consumes 35-40 tons of fuel per day. But the above figures can be reduced by 5-10 times!

Auxiliary sailing rigs have been developed, which provide high sail thrust and make it possible, in winds of 5-10 m/s, to reduce the average fuel consumption during the movement of a cargo ship by 50-70%, and in winds of greater strength, to completely eliminate the need for the operation of a mechanical power plant, without reducing speed. Such weapons can be used, first of all, on bulk carriers with a deadweight of 10-25 thousand tons.
The figure shows a cargo ship with a displacement of 37,000 tons (deadweight 23,000 tons) with three rigid rotating glider-type wing sails1. Each wing has a span of 60 m and a chord of 10 m. The total sail area is about 1800 m2. The design speed of the vessel with a wind of 7 m/s is 16 knots, with a wind of 12 m/s - 23 knots. Reducing the required fuel supply (20 times) increases the useful volume of the vessel. The maximum power of ship engines can be reduced by 10 times, using them only for taxiing and in emergency situations.
There is no need to remove glider-type sailing rigs in stormy weather or hurricane winds; you need to put the stabilizers at zero angles and release the fixation of the sailing installation, then it will become an ordinary weather vane, the resistance of which is less than the resistance of a ship's mast.
Glider-type sailing rigs make it possible to reduce water resistance to the movement of the vessel, as it provides some aerodynamic unloading due to the appearance of lifting force on the wing sails. Such sails increase the stability of the vessel, since the traction force of the sails passes through its CG, which eliminates the occurrence of heeling. And the large area of ​​the sails themselves dampens the ship when it rolls: in high seas, the sails are not able to instantly move large masses of air. The ship seems to hang on sails-wings, which provides up to 5% of the aerodynamic unloading of the ship.
The enormous economic efficiency of glider-type sails-wings is also confirmed by calculations performed at the Moscow Aviation Institute when developing a sailing dry cargo ship with a displacement of 170 thousand tons for “trade wind” shipping directions. A winged cargo ship can have a fully automated system, even for remote control of the sail from the shore. Using satellite communications, the center receives all weather and situation data, computers optimize the course and schedule of the vessel and transmit commands to the onboard control panel. The “hulk” ship can sail in automatic mode - without a crew. The wind, in accordance with the program, will drive it to a given point on the globe to meet the crew, which is disembarked from a helicopter or service vessel before entering the port, or to pass a difficult section of the route.

Modern achievements of science and technology make it possible to ensure complete safety of this version of the Flying Dutchman for navigation using traditional watercraft.
All sailboats discussed in this article are protected by patents for inventions. Projects of ships with aerodynamic sailing rigs for high-speed, environmentally friendly maritime transport were exhibited at the XXV International Salon of Inventions in Geneva in 1997 and were awarded a diploma and a bronze medal.

Few people remember that the device, which uses aerodynamic forces for movement, was created over five thousand years ago. It was a self-propelled vessel with a sail propulsion that worked exactly like the wing of a modern airplane.

The only difference is that the lift of an airplane wing is directed vertically upward, and the pulling force of a sail is directed horizontally. In fact, the movement of a sailboat is the same flight, only on its side. It took mankind five thousand years to turn a sail into an aircraft wing. And it took about half a century to turn an aircraft wing into a propulsion device for a classic or wheeled yacht or iceboat.

The effect was amazing. The speed parameters of experimental yachts with rigid sails turned out to be no worse than those of motor boats. The fact is that an ordinary sail does not have very good “aerodynamics” - just compare a hang glider with its wing-sail with a record-breaking glider: the former has an aerodynamic quality barely reaching 8 units, and the latter has over 40! True, a wing with a flat-convex or concave-convex profile has the highest quality.

Well, for a sailboat it was necessary to use a wing with a symmetrical profile, which had worse pulling properties, but worked equally when moving on both starboard and port tacks. Ship modellers found a way out of this situation easily - they installed a wing with a flat-convex or concave-convex profile on their yachts and, when changing tack, simply turned it upside down.

Well, restless inventors equipped full-size yachts with a wing that changed the profile due to the deflection of the flap. Good results were also shown by yachts with a relatively narrow wing of a symmetrical profile, more like a very wide mast in combination with an equally narrow sail with rigid battens that served as a flap.

Today we introduce ship modelers to model of a sailing catamaran class "P", equipped with a self-orienting sail-wing of a symmetrical profile. We think that the design of the sailboat will also be of interest to fans of “big” sailing. A few words about the principle of self-orientation of the sail-wing.

Take a look at the geometric diagram catamaran- in addition to the hinged wing, the aerodynamic system includes a stabilizer - exactly the same as on a classic glider - which automatically sets the sail-wing at the optimal angle of attack relative to the direction of the apparent wind. Design models not too complicated. Catamaran hulls are glued onto a wooden blank made of fiberglass and epoxy binder, and first the lower part of the hull is formed up to the deck, and then the upper part.

The shell thickness of the case is about 2 mm. After gluing, the upper and lower mouths are adjusted to each other and the shells are reinforced with a set of plywood frames, keel beams and stringers. It is mandatory to provide scuppers on the frames, and holes with plugs in the transom to drain water entering the hull.

On frames No. 3 and No. 6, wooden blocks with steel threaded rods glued into them are installed - they are intended for connecting the hulls to the bridge. At the same stage, plywood keels are installed on the hulls, and then decks. All these parts are secured with epoxy glue, to which any powdered thickener is added - from cement and gypsum to flour and starch.

Tail feathers are cut from 6 mm thick plywood; The profile of the feathers is flat, symmetrical, with a rounded leading edge and a pointed trailing edge. The pen is mounted on each housing using an M5 threaded rod and a wing nut. The finished housings are puttied, sanded and painted with auto enamel of a suitable color.

The H-shaped bridge is made of pine slats and reinforced with 2mm plywood overlays. The bridge is assembled using epoxy glue. The finished bridge is covered with several layers of parquet varnish. The sail-wing is made using classical aircraft modeling technology. The wing frame consists of a double-flange spar made of pine slats, pine leading and trailing edges and a set of ribs.

The latter are best cut from ordinary school rulers with a thickness of 2-3mm. The stabilizer mounting beams are also cut from 3 mm thick rulers. The central part of the wing is sewn up with 1.5 mm linden veneer. Between the flanges of the spar in the root part of the wing, a beech block with a central hole drilled in it with a diameter of 8 mm, which is the wing hinge bearing, is fixed with glue.

To fasten the stabilizer to the beams, brackets embedded in it are intended; their fixation on the beams is carried out using four screws glued. Today we are introducing ship modellers to model sailing catamaran class "P", equipped with a self-orienting sail-wing of a symmetrical profile.

We think that the design of the sailboat will also be of interest to fans of “big” sailing. A few words about the principle of self-orientation of the sail-wing. Take a look at the geometric diagram of the catamaran - in addition to the hinged wing, the aerodynamic system includes a stabilizer - exactly the same as on a classic glider - which automatically sets the sail-wing at the optimal angle of attack relative to the direction of the apparent wind.

Design models not too complicated. Catamaran hulls are glued onto a wooden blank made of fiberglass and epoxy binder, and first the lower part of the hull is formed up to the deck, and then the upper part. The shell thickness of the case is about 2 mm. After gluing, the upper and lower mouths are adjusted to each other and the shells are reinforced with a set of plywood frames, keel beams and stringers.

It is mandatory to provide scuppers on the frames, and holes with plugs in the transom to drain water entering the hull. On frames No. 3 and No. 6, wooden blocks with steel threaded rods glued into them are installed - they are intended for connecting the hulls to the bridge.

At the same stage, plywood keels are installed on the hulls, and then decks. All these parts are secured with epoxy glue, to which any powdered thickener is added - from cement and gypsum to flour and starch. Tail feathers are cut from 6 mm thick plywood; The profile of the feathers is flat, symmetrical, with a rounded leading edge and a pointed trailing edge.

The pen is mounted on each body using an M5 threaded rod and a wing nut. The finished housings are puttied, sanded and painted with auto enamel of a suitable color. The H-shaped bridge is made of pine slats and reinforced with 2mm plywood overlays.

The bridge is assembled using epoxy glue. The finished bridge is covered with several layers of parquet varnish. The wing-sail is made using classic aircraft modeling technology. The wing frame consists of a two-flange spar made of pine slats, pine leading and trailing edges and a set of ribs.

The latter are best cut from ordinary school rulers with a thickness of 2-3mm. The stabilizer mounting beams are also cut from 3 mm thick rulers. The central part of the wing is covered with 1.5 mm lime veneer. Between the flanges of the spar in the root part of the wing, a beech block with a central hole drilled in it with a diameter of 8 mm, which is the wing hinge bearing, is fixed with glue.

The wing skin is a lavsan film that is attached to the wing frame with “BF” or “Moment” glue. The sheathing is stretched using a conventional electric iron. The stabilizer is cut from dense foam plastic of the “PS” brand. It is a flat plate about 8 mm thick, the front part of which is rounded and the back part is pointed.

To fasten the stabilizer to the beams, brackets embedded in it are intended; their fixation on the beams is carried out using four screws glued with epoxy to the brackets. No nuts are required for the connection; the beams are simply moved apart a little and the screws are passed through the holes. This mounting method makes it easy to move the stabilizer “upside down” when launching the catamaran on a different tack.

Before launch models You should make sure that the catamaran with the wing-sail removed moves strictly straight from a push by hand, otherwise you will have to adjust the course using the rudders. Before starting to move, the catamaran must be oriented in accordance with the intended course, and the stabilizer should be installed so that the angle of attack of the wing relative to the wind is positive.

When the model is launched on a different tack, the stabilizer turns upside down. On a gybe course - when the wind blows strictly at the stern of the sailboat - the wing is installed across the direction of the flow and is fixed in this position using a sheet attached to the trailing edge of the sail. The methods and materials for manufacturing hulls and wings described above are far from the only ones.

In particular, very good hulls and wing sails can be made from foam plastic. In this case, the former are covered with two layers of fiberglass, and the latter are only primed with epoxy glue.

Geometric scheme catamaran class "P"

The design of the catamaran hull (the hull shell is not shown on the plan view): 1-frame No. 1; 2-frame No. 2; 3-keel; 4-keel base; 5-frame No. 4; 6-keel beam; 7-frame No. 5; 8-transom board; 9.16-bases of connecting studs; 10-joint studs; 11-frame No. 6; 12-stringers; 13-scupper; 14-frame No. 3; 15-hull shell; 17-joint rudder assembly

Sail-wing operation diagram

Bridge: 1-front bridge beam; 2.4-pads; 3 - longitudinal beam of the bridge; 5-rear bridge beam; 6-cradle

Wing hinge unit: 1 - leading edge of the wing; 2-spar; 3 - rib; 4-back edge; 5-wing bevel stitching; 6-longitudinal bridge beam catamaran; 7-pads; 8,10-nuts M8; 9-root half-rib wing; 11-wing hinge bearing housing; 12-axis wing hinge

Theoretical drawing of the case

Sail-wing: 1 - root half-rib; 2-wing hinge bearing housing; 3-spar; 4 - ribs; 5 - leading edge; 6.8-pads; 7-stitching of the central part of the wing; 9-rear edge; 10 - boss; 11-stabilizer beams; 12 - fixing screws; 13 - stabilizer bracket; 14-stabilizer; 15-wing bevel stitching

Only at a small angle of attack, when lifting force has not yet formed on the sharp and thin profile, does the sail flow around an air flow that is equally smooth on the lower and upper sides. With a slight increase in the angle of attack, the critical point moves to the lower side of the profile and the flow has to go around the sharp edge at high speed. As a result, a significant vacuum is formed at the incoming edge and, under the influence of this rarefaction, the boundary layer breaks away from the surface of the profile, forming a vortex bubble on its back. At a sufficiently high wind speed, the flow quickly absorbs the energy of the vortices and the layer reattaches to the profile surface at some distance from the incoming edge (Fig. 21).

The vortex bubble, which increases in size as the angle of attack increases, introduces significant changes in the distribution of reduced pressure along the leeward side of the sail compared to the pressure distribution shown in Fig. 10 on a rigid profile with a thick rounded leading edge. Let us recall that it is the vacuum on the leeward side of the sail that plays the main role in creating lift and, consequently, thrust on courses sharp to the wind.

In Fig. Figure 21 shows the results of vacuum measurements on a rigid convex-concave profile, similar to a sail. At low angles of attack, the profile flows around in a smooth laminar flow.

At a= 4° you begin to separate the boundary layer. At this moment, the highest vacuum is reached, the peak of which is located near the incoming edge.

At a= 60 vortex bubble occupies about 25% of the profile chord on the leeward side b. The vacuum decreases, and its diagram becomes smoother.

At a= 10° bubble covers the entire width of the profile, its thickness is 3.5% b. The pressure increases 2.5 times compared to the vacuum at a= 4°; There is practically no rarefaction peak - it is evenly distributed over the entire width of the profile. This means that the lift force has decreased significantly, and the drag has increased (see Fig. 27).

Thus, on a close-hauled course, an increase in the angle of attack of the sail to the apparent wind by more than 5-6° is undesirable. On a real sail, the vortex bubble is a cylindrical roller invisible to the eye, spreading over the entire height of the sail. The wider the sheet is selected, the more of the leeward surface of the sail is captured by the vortex roller, reducing lift.

To select the optimal angle of attack, in recent years, flow indicators have been used in the form of ribbons made of thin fabric, fixed at a certain distance from the luff on both sides of the sail (Fig. 22).

Such a place is a point B return of the boundary layer to the surface of the sail. At angle of attack a= 5° it is spaced from the luff by approximately 15% of the width of the sail in each cross section. As soon as the vortex bubble reaches this point, the indicator strip on the leeward surface of the sail, previously directed back along the air flow, will deflect upward and forward, indicating the occurrence of vortices here. Further selection of sheets - increasing the angle of attack - is not only useless, but even harmful, as it leads to a large loss of lifting force.

Installing three or four similar indicators, evenly distributed along the height of the jib, makes it easier for the helmsman to correctly select the course when tacking. Having chosen the most advantageous sheets for a given course, steer the yacht in such a way that the indicators on the windward side of the jib tremble slightly, and on the leeward side they are extended towards the luff (Fig. 23).

The reason for the drop in lift on the sail is the disruption of the flow on its leeward side when the angle of attack increases (which corresponds to picking up the sheets or stalling the yacht), so the main role is played by indicators located on the leeward side. If they begin to rise and make erratic movements, it means that it is necessary to bring the yacht to the wind or to lower the sheets.

The angle of attack at which lift stops increasing is called the critical angle of attack. Its value depends on the depth and shape of the “belly” of the sail, the aerodynamic aspect ratio (it is calculated for sails in the same way as for keels and rudders), and the presence of a mast or forestay fairing at the luff.

Rice. 23. The behavior of the indicators depending on the angle of attack of the sail.

In a weak wind, the air flow occurs at lower angles of attack than in a strong wind. When setting the jib in front of the mainsail, due to the increase in flow speed in the gap between both sails, the moment of stall shifts towards higher angles of attack. The mast has the opposite effect; vortices breaking off from it onto the leeward side of the sail contribute to stalling the flow at a lower angle of attack.

As the angle of attack increases beyond the critical value, the lift force decreases and at the same time the drag increases. At a= 90° no lift force is created on the sail: it only has drag.

Polar sails. A characteristic of the aerodynamic qualities of a sail is the polar - a graph of changes in lift depending on drag and angle of attack (Fig. 24, a). In order for the polar to be applied to a sail of any size, it is not the force values ​​that are plotted along the coordinate axes, but the dimensionless lift coefficients Su and drag Cx. The data for constructing polars is obtained by blowing sail models in wind tunnels.

Using a polar, you can determine the magnitude of lift and drag, as well as their components - projections on the direction of movement of the yacht. By lowering, for example, from the polar point corresponding to the angle of attack a= 20°, perpendicular to the axis of motion of the yacht, you can find the value of the thrust force coefficient St as a segment of straight line AO. The length of the perpendicular AB itself will be nothing more than the drift force coefficient Cd. Multiplying the numerical values ​​of the coefficients St and Cd by the sail area S and the speed pressure ( * v**2) / 2, we can obtain the magnitude of the corresponding forces.

The sail polar allows you to determine the most favorable angle for setting the sails on a given course in relation to the wind. The maximum thrust is obviously determined by the perpendicular to the axis of motion of the yacht, which is also tangent to the polar. Attack angle a= 14°, determined by the point of tangency C, will be the most advantageous in this case. The corresponding angle of installation of the sail relative to the yacht’s DP can be easily found by subtracting from the heading angle (relative to the apparent wind drift) and the angle of attack a(see Fig. 19).

It is easy to carry out similar constructions for various values ​​of the heading angle and determine the most advantageous sail installation angles and the corresponding angles of attack. You can be sure that for a given sail, at almost all acute angles to the wind, right up to the backstay, the most advantageous angles of attack are close and are within 14-15°.

Furling the sail. The choice of the optimal angle of attack of the sail is associated with its ability to twist, i.e., change the angle of attack in height. When choosing sheets, only the lower third of the sail can be controlled; in the upper part, the fabric has the ability to deviate somewhat to the leeward, thereby reducing the angle of attack. If special means are not provided to control sail twist, the difference in angle of attack or twist angle can reach 20°. And since the sail is selected based on the behavior of its upper part (until the fabric at the luff stops rinsing), the lower part ends up working with excessive angles of attack. Here the flow may stall on the leeward side and the lift force may drop accordingly. Consequently, the thrust of a furled sail turns out to be lower than if each of its height sections had an optimal angle of attack.

The twisting of the sail is especially noticeable on full courses and in fresh winds, when the sheets are pulled out and the tip of the boom lifts up. In this case, the upper part of the sail goes into the wind and almost floats, and the lower part operates at too high an angle of attack.

To reduce the twisting of the mainsail, most yachts use boom guys to prevent the toe from lifting up, as well as a boom-sheet with one or two transverse shoulder straps extending across the entire width of the yacht. When the boom-sheet slider is moved to the side of the yacht, the pull of the sheets becomes almost vertical, thanks to which it is possible to keep the luff of the sail tighter on sharp courses.

Evidence of correct adjustment of the boom guy tension can be seen in the simultaneous (over the entire height) rinsing of the fabric at the luff when the sheet is being pulled out.

It would be a mistake to assume that the sail should not have any vertical twist at all, that is, have all sections rotated relative to the boom at the same angle. On large yachts, it is necessary to take into account the change in speed and direction of the apparent wind along the height and the presence in the upper part of the sail of air flow from the high pressure zone to the leeward side. Depending on the sail height and wind speed, the difference in angles of attack is from 3-5° in close-hauled to 10-12° on the backstay course. Within such limits, twisting the sail is permissible and contributes to more efficient operation.

Air circulation around the wing (see Fig. 10), which appears along with the aerodynamic force, causes transverse air flows that are insignificant in speed VI at the incoming and outgoing edges. Due to the flow of air over the edges at the ends of the wing, these flows intensify and deflect the main flow flowing onto the wing, so that the angle of attack of a rigid triangular Bermuda sail increases as it approaches the tip and, near the halyard corner, is approximately 20% higher than the angle of attack of the middle part of the sail. Near the boom, the actual angle of attack, on the contrary, decreases somewhat.

Thus, if the sail had no twist, then its upper part would work at supercritical angles of attack and would practically not participate in the creation of the driving force. An experienced crew constantly monitors and adjusts the twist of the sail depending on the wind force and the course of the yacht by pulling the boom and moving the lower block of the boom sheet along the shoulder strap.

Mast influence. The mast is a source of turbulence, which has a particularly adverse effect on the flow on the leeward side of the sail. Here, the vortex wake of the mast reduces the vacuum, as a result of which the magnitude of the lifting force decreases. In addition, the mast itself has a fairly high drag.

An important role is played by the shape of the cross section of the mast, especially its leading edge, on which the flow is formed. It is important that on a close-hauled course, when the yacht is sailing at an angle of 25-30° to the apparent wind, the vortex trail coming off the leeward side of the mast has a minimum width. The sail behind a mast with a parabolic cross-section and a blunt stern edge has a higher aerodynamic quality than behind a mast with an elliptical cross-section (Fig. 25). The most optimal option is a mast with a sail secured by the luff near its leeward side: the quality of its work is 40% higher than sails with an elliptical mast. This is further evidence that the negative influence of the mast mainly extends to the leeward side of the sail.

A mast with a large cross-section can reduce the lift of a sail by 25% compared to a sail set on a forestay. The loss of lifting force is especially large when setting the sail on a rail with sliders, when air flows into the gap between the mast and the sail from the windward side of the sail into the region of the peak vacuum on the leeward side. Masts with a cylindrical cross-section, without tapering towards the top, are unsuccessful: in the upper part the ratio of the diameter of the mast to the width of the pair decreasing here becomes large. It may turn out that the part of the sail near the halyard angle will not participate at all in creating lift, and, consequently, thrust on a close-hauled course.

The most common masts on yachts are those with an oval cross-section, with a ratio of about 3:2 , providing greater longitudinal rigidity. Teardrop and other types of streamlined profiles are only practical if the mast rotates to position it at the best angle to the apparent wind when changing tack. Buoys and catamarans are usually equipped with such masts.

Let us determine how a traction force is generated on the sail, which imparts movement to the sailing vessel.

All reasoning is purely qualitative. When presenting, assumptions are made and details that are not considered are not fundamental, from the point of view of the physical principles of the operation of the sail, but simplify both the presentation of the issue and the understanding of the material being presented.

An air flow is applied to the sail, determined by the speed and direction of the apparent wind.

In this case, we determine, before starting our consideration, that the sail is a vertical wing and divides the flow of incoming air into two parts. One part of the air flow passes along the leeward side of the sail, and the second part along its windward side. Both streams meet behind the luff of the sail. On the leeward side of the sail (convex), the flow travels a greater distance than along the windward side. Consequently, the flow speed in the leeward direction is shown in Fig. 6 rone sails above.

According to Bernoulli's law, pressure is lower where the flow rate is higher. Thus, a vacuum appears on the leeward side of the sail, which causes the sail to shift towards lower pressure (Fig. 6). The amount of vacuum that occurs on the leeward side of the sail is proportional to the flow speed.

The displacement of a sailing vessel occurs under the influence of an aerodynamic force, which is the result of the action of two forces on the sail - the force of air resistance to the movement of the sail and the lifting force (Fig. 7), which imparts this movement to the sail. In turn, the resulting aerodynamic force can be decomposed into two components - a vector in the direction of movement of the vessel and a per -

rice. 7 is a vector perpendicular to it. The first vector, directed along the movement of the vessel, is the traction force, which imparts movement to the sail and through it to the vessel, and the second is the drift force (heeling force), which causes drift to the leeward side (Fig. 8). In the literature and in the figure, the force perpendicular to the traction force is often called the heeling force. This statement is not correct and the authors use it to replace the heeling moment, which arises as a result of the vessel’s interaction not only with the wind, but also with water. This issue will be discussed later when considering the resultant hydrodynamic force and the leverage between the ship's lateral drag force and the drift force.

Based on the fact that the value

rice. 8 lift force is proportional to the speed of the oncoming flow, we can conclude that a faster ship can move more sharply towards the apparent wind. This is explained by the fact that with a smaller ratio of thrust force to drift force, the value of thrust force, at high apparent wind speeds, will be sufficient to ensure the movement of the vessel. For ships moving in displacement mode, this gain will be insignificant since the increasing speed of the vessel will cause an increase in the drag force and a balance will occur between the thrust and drag forces. For planing vessels with low drag, it is possible to move at very sharp angles to the apparent wind.

For the sail to operate effectively, it must be placed at a certain angle to the oncoming air flow. This angle is called the angle of attack of the sail and is defined as the angle between the direction of the wind and the chord of the sail.

The angle of attack of a sail is very dependent on the cross profile of the sail. The optimal angle of attack for most sails is around 15 degrees (Figure 9).

At angles of attack greater than 15 degrees, the flow begins to stall and the laminarity of the flow on the leeward side of the sail is disrupted. In this case, the flow around the sail is disrupted (the flow becomes turbulent), which leads to a decrease in the flow speed and, accordingly, a decrease

vacuum on the leeward side of the sail. In addition, turbulent flow increases friction against the sail, and changes the cross-section of the sail in

rice. 9 area of ​​the luff (Fig. 10). All these phenomena, which occur as the angle of attack of the sail increases, lead to a decrease in the efficiency of the sail as a wing and a decrease in the sail's thrust.

At angles of attack less than 15 degrees, the flow on the windward side of the sail breaks down. Since the sail is a soft wing and its shape is provided by Fig. 10 only by the flow of incoming air, then in the limit, at very low angles of attack, the sail loses its shape and stops working.

In both cases, the efficiency of the sail deteriorates, which

rice. 11 pics. 12

leads to a decrease in sail thrust. Therefore, every time the course changes, it is necessary to adjust the sails.

A sailing ship can move at angles to the wind ranging from 30-40 degrees to 180 to each side. In this case, the sails are located at different angles to the ship's DP, but always at an angle to the apparent wind, ensuring efficient operation of the sail.

In Fig. Figure 11 shows the change in the position of the sails relative to the DP when the yacht falls downwind. The term used here is to go more fully.

In Fig. Figure 12 shows the change in the position of the sails relative to the DP when the yacht is brought to the wind. The term used here is to go steeper (or sharper) into the wind.

In Fig. Figure 13 shows the yacht's courses relative to the apparent wind and the position of the sails on each course.

This pattern can be divided into two halves based on the diameter perpendicular to the direction of the apparent wind. This direction of the ship's movement (90 degrees to the wind) is called gulfwind (half wind).

Courses located above this line are called acute, and below this line - full.

Sharp courses include close-hauled (from 30-40 to 90 degrees to the wind) and left-handed (0 degrees to the wind).

Leventik is not a working course, since a sailing ship cannot move strictly against the wind (as evidenced by the lapping sail in the picture).

The red sector in the upper half of heading angles is non-working, since movement in this zone is possible, but not effective.

Full courses include backstay (90 to 180 degrees to the wind) and jibe (180 degrees to the wind).

It is interesting to consider the green sector in the area of ​​the gybe course. This is also an undesirable sector of heading angles, since in this sector the movement of a sailing vessel with an oblique rig (wing) is not effective. The sail works like a sail (due to the sail area, and not due to the properties of the wing). The speed of the ship's movement downwind is limited by the wind speed and the ship's controllability on this course, especially in rough seas, is not high.

rice. 13 The second interesting line of division of this pattern is the vertical diameter, coinciding with the direction of the wind, which divides this pattern into two halves. In the left half of the picture, the ship is sailing on starboard tacks relative to the wind, and in the right half, on port tacks.

1. Tack is the ship's course relative to the wind:

Wind from the port side - port tack;

The wind is from the starboard side - starboard tack.

2. Tack is the part of the ship's path between turns.

In Fig. Figure 14 shows the directions of the apparent wind at the same courses relative to the true wind and the position of the sails on each course.

From ri analysis The table follows that with equal speed of the true wind and the speed of the vessel at a heading angle of 45 degrees to the true wind, the sailing ship has a heading angle to the apparent wind equal to ~ 22 degrees.

And when moving on a backstay course relative to the true wind, the ship goes close-hauled relative to the apparent wind. And only when the backstay is heading the apparent wind moves away to the gulfwind

In addition to the position of the sail relative to the ship's DP, it is interesting to consider the shape of the sail depending on the ship's moving conditions.

The transverse profile of the sail – the “belly” of the sail, which is measured as a percentage of the length – is very important. 14 we have sails along the chord (Fig. 15).

Pot-bellied sails provide more lift, but have high drag (Figure 15).

Flat sails do not provide much lift, but at the same time they have little drag (Fig. 15).

It follows from this that for heavy ships with high drag of the underwater part of the hull, it is advisable to use sails with a large sail depth, providing “high thrust” at low apparent wind speeds. And for sports vessels, especially planing ones, designed for high speeds, it is advisable to use “flat” sails that have little drag to the air flow, but provide “good traction” at high apparent wind speeds.

Of great importance is the shape of the sail in the area of ​​the luff - the “forehead of the sail”. When the “belly” of the sail is shifted forward, the sail becomes “foreheaded,” and when it is shifted back, we get a “flat entry” sail.

With a “flat entry,” the course sharpness is higher, but the sail is critical to changes in the angle of attack. High precision in control is required and with any change in course it is necessary to adjust the sails (Fig. 12).

rice. 15 pics. 16

With a fronted sail (the belly is shifted forward), the resistance of the sail increases and the sharpness of the course relative to the wind decreases, but the range of course changes without additional adjustment of the sails (steering range or course sector) increases due to an increase in the range of angles of attack of the sail at which it continues to work effectively (Fig. . 12).

rice. 17

A sail with a belly shifted forward is advisable to use in complex designs. 18

weather conditions, in high seas, when it is necessary to ensure the possibility of a constant, slight change in course to ensure the stability and safety of the vessel (for example, crossing a wave crest at a right angle or the impossibility of accurately keeping the yacht on course in gusty winds).

Changing the belly of the mainsail is achieved by bending the mast. When the mast bends, the front and rear luffs of the sail move apart and the sail becomes flatter due to this (Fig. 17), while the belly of the sail shifts back. The belly of the mainsail in its lower part is modified by stuffing the main sheet. To move the belly forward in order to restore its correct position in the region of 40-50 percent of the chord, the main halyard is stuffed. With further stuffing of the mainsail halyard, the belly shifts further forward and the lobe of the sail increases.

The jib is adjusted in the same way. Stuffing the forestay changes the depth of the belly, and padding the jib halyard changes the position of the belly and the lobe of the sail.

In addition to the transverse profile of the sail, its longitudinal profile (change in the profile of the sail in height) is of great interest and importance. To ensure proper sail performance, the sail must have a pitch twist that provides a constant angle of attack of the sail relative to the apparent wind.

Since the wind speed increases with increasing distance from the ship’s deck, and the speed of the sail in the horizontal plane does not change, the direction of the apparent wind changes (the angle between the ship’s course and the direction of the apparent wind increases - the wind “moves away”) and its intensification (Fig. 18 ).

To compensate for changes in the direction of the apparent wind, it is necessary to change the position of the sail in height - the angle of attack of the sail. This is achieved by turning

rice. 18 fig. 19

The angle towards the leeward side of the upper part of the sail is greater than that of the lower part (Fig. 20).

The twisting of the mainsail is ensured by changing the “stuffing” of the boom guy and the position of the boom-sheet carriage on the chase.

Twisting of the jib is ensured by the padding of the jib sheet and the position of the jib sheet carriage on the chase. By moving the carriage forward, the sail becomes fuller and the vertical twist of the sail is reduced. By moving the carriage back, the sail becomes flatter and the sail's twist increases in height.

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