Hovercraft makes it possible to move on water and on land. In this article, we will look at how to do it yourself.
Hovercraft - what is it
One of the ways to combine a car and a boat has become a hovercraft, which has good maneuverability and high speed through the water due to the fact that its hull does not sink under the water, but, as it were, glides over its surface.
This method allows you to move economically and quickly, since the sliding friction force and the resistance force of water masses are, as they say, two big differences.
But, unfortunately, despite all the advantages of a hovercraft, its field of application on the ground is limited - it can move not on any surface, but only on a rather soft surface, such as sand or soil. Asphalt and hard rocks with sharp stones, and industrial debris, they will simply tear the bottom of the ship, rendering the air cushion unusable, and it is thanks to it that the SVP moves.
Therefore, hovercraft are used mainly where you need to swim a lot and drive a little, otherwise amphibious cars with wheels are used. SVPs are not widespread today, but in some countries rescuers work for them, for example, in Canada, and there is also evidence that they are in service with NATO.
Buy a hovercraft or do it yourself?
Hovercraft are quite expensive, for example, an average model costs about 700 thousand rubles, while the same scooter can be bought 10 times cheaper. But of course, by paying money, you get factory quality, and you can be sure that the ship will not fall apart right below you, although there have been such cases, but still the probability is lower here than in the case of a self-made one.
In addition, manufacturers mainly sell "professional" hovercraft for anglers, hunters, and all kinds of services. However, amateur vessels are extremely rare, and they are mainly products self made, due, again, to their low popularity among the people.
Why hovercraft haven't won a lot of love
Main reasons:
- High price and expensive service. The fact is that the parts and functional units of the SVP wear out very quickly and need to be replaced, and the purchase and installation also cost a lot of money. Therefore, only a rich person can afford it, but even for him every time it is very inconvenient to take a broken ship to a repair shop, since there are only a few such workshops, and they are mainly located only in large cities... Therefore, as a toy, it is more profitable to buy, for example, an ATV or jet ski.
- Due to the screws, they are very noisy, so you can only ride with headphones on.
- You can not swim and go against the wind, as the speed is greatly reduced.
Amateur SVPs were and remain only a way of showing their design abilities for those who can maintain and repair them themselves.
DIY process
How to catch more fish?
In my 13 years of active fishing, I have found many ways to improve my bite. And here are the most effective ones:- Bite activator. Attracts fish in cold and warm water with the help of pheromones and stimulates their appetite. Pity that Rosprirodnadzor wants to ban its sale.
- More sensitive gear. Read the appropriate guides for your specific tackle type on the pages of my site.
- Baits based on pheromones.
It's not easy to make a good SVP, but if you think about it, then most likely you have either the ability or the desire, but keep in mind that if you do not have a technical background, forget about this idea, because your hovercraft will crash in the first test drive.
So, you should start with a drawing. Design your SVP. How do you want to see it? Rounded like the Soviet MI-28 helicopter or angular like the American Alligator? Should it be streamlined like a Ferrari, or a Zaporozhets-like one? When you have answered yourself these questions, start creating your drawing.
The figure shows a sketch of the SVP, which is in service with the Canadian Rescue Service.
Technical characteristics of the vessel
An average home-made SVP can develop a fairly high speed - which one exactly - depends on the mass of passengers and the boat itself, as well as on the engine power, but in any case, with the same engine parameters and weight, an ordinary boat will be several times slower.
With regard to the carrying capacity, we can say that the model of a single hovercraft proposed here is capable of withstanding a driver weighing 100-120 kg.
You will have to get used to the control, since it differs significantly from a regular boat, firstly, because there are completely different speeds, and secondly, fundamentally different ways movement.
The faster the hovercraft moves, the more it drifts when cornering, so you need to lean a little to the side. By the way, if you get used to it, you can "drift" quite well on a hovercraft.
Necessary materials
All you need is plywood, styrofoam and a special Universal Hovercraft kit, designed specifically for self-taught engineers, containing everything you need.
Insulation, screws, air cushion fabric, epoxy, glue and more are all in ready-made kit, which you can order from their official website for $ 500, and will also include several plan options with blueprints.
Manufacturing of the case
The bottom is made of foam, 5-7 cm thick, calculated for one person, if you want to make a ship for two or more passengers, then attach another sheet of the same type below. Further, in the bottom, you need to make two holes: one for the air flow, and the second to ensure the inflation of the pillow. You can use a jigsaw.
Next, you need to insulate the lower part of the case from water - fiberglass is ideal for this. Apply it to the styrofoam and epoxy it. But the surface may form irregularities and air bubbles, to prevent this, cover the fiberglass plastic wrap, and cover with a blanket. Put another layer of plastic on top and tape it to the floor. Use a regular vacuum cleaner to blow out the air from under the resulting "sandwich". The bottom of the case will be ready in 2.5-3 hours.
The upper part of the body can be made arbitrary, but you should not forget about the aerodynamics. Making a pillow is easy. It is only necessary to correctly fix it and synchronize it with the bottom - that is, to make sure that the air flow from the engine passes through the hole into the pillow without losing efficiency.
Make the pipe for the motor from styrofoam, do not miscalculate the dimensions so that the screw fits into it, but the gap between its edges and the inside of the pipe is not very large, as this will reduce the thrust. The next step is to install the motor holder. In fact, it is just a stool with three legs, which are attached to the bottom, and the engine is placed on top of it.
Engine
There are two options - a ready-made engine from Yu.Kh. or homemade. You can take it from a chainsaw or a washing machine - the power they give is quite enough for an amateur SVP. If you want something more, you should take a closer look at the motor from the scooter.
Be sure to balance the propeller blades when installing them, as if one weighs more than the other, the centrifugal forces will loosen the propeller, and the resulting vibration will quickly destroy the entire engine.
Is the hovercraft reliable?
Factory SVPs, with frequent use, break down about once every half a year, but these are all problems that do not require overhaul... Most often, the pillow and the air injection system fail. The likelihood that a well-assembled hovercraft will fly apart under your feet is extremely small, for this you need to bump into some large stone or piece of wood at high speed, but even this case, there is a chance that the air cushion will protect you.
In Canada, rescuers operating on such hovercraft repair them on the go, and problems related to the pillow are fixed in a special garage.
The model described here is, in principle, reliable, but only if:
- Materials were of adequate quality, including adhesives and epoxies.
- The engine has not completed its service life.
- The connections are secure.
- That is, how much you can trust your hovercraft depends entirely on you.
If you make a SVP as a toy for a child, then it is better to buy a ready-made one, otherwise you should have very good data as a designer. If you create just for your own pleasure, and you do not have a lot of technical experience, then it is better, just in case, not to let children at the wheel.
But there is another option - to make a two-seater SVP with the provided security system, while the child will sit in front, and you will sit in the back between him and the engine.
Once in winter, when I was strolling along the banks of the Daugava, looking at the snow-covered boats, I had a thought - create an all-season vehicle, i.e. an amphibian that could be used in winter.
After much deliberation, my choice fell on a double hovercraft... At first, I had nothing but a great desire to create such a structure. The technical literature available to me summarized the experience of creating only large SVPs, and I could not find any data on small devices for walking and sports purposes, especially since our industry does not produce such SVPs. So, one could only rely on one's own strength and experience (about my amphibious boat based on the motorboat "Yantar" at one time it was reported in "KYA"; see No. 61).
Foreseeing that in the future I might find followers, and if the results are positive, the industry might also be interested in my apparatus, I decided to design it on the basis of well-mastered and commercially available two-stroke engines.
In principle, an air-cushion vehicle experiences significantly less stress than a traditional planing boat hull; this allows the design to be made lighter. At the same time, an additional requirement appears: the body of the apparatus must have low aerodynamic resistance. This must be taken into account when developing a theoretical drawing.
| Basic data of amphibious hovercraft | |
|---|---|
| Length, m | 3,70 |
| Width, m | 1,80 |
| Board height, m | 0,60 |
| Air cushion height, m | 0,30 |
| Hoisting unit power, l. With. | 12 |
| Traction unit power, hp With. | 25 |
| Payload, kg | 150 |
| Total weight, kg | 120 |
| Speed, km / h | 60 |
| Fuel consumption, l / h | 15 |
| Fuel tank capacity, l | 30 |
1 - steering wheel; 2 - instrument panel; 3 - longitudinal seat; 4 - lifting fan; 5 - fan casing; 6 - traction fans; 7 - fan shaft pulley; 8 - engine pulley; 9 - traction motor; 10 - muffler; 11 - control flaps; 12 - fan shaft; 13 - bearings of the fan shaft; 14 - windshield; 15 - flexible fence; 16 - traction fan; 17 - traction fan casing; 18 - lifting motor; 19 - lifting engine muffler;
20 - electric starter; 21 - battery; 22 - fuel tank.
I made a set of the case from spruce slats with a cross section of 50x30 and sheathed it with 4 mm plywood on epoxy adhesive... I didn’t do pasting with fiberglass, fearing an increase in the weight of the apparatus. To ensure unsinkability, I installed two watertight bulkheads in each of the side compartments, and also filled the compartments with foam.
A twin-engine scheme of the power plant is selected, i.e. one of the engines works to lift the apparatus, creating overpressure(air cushion) under its bottom, and the second provides movement - creates horizontal thrust. The lifting engine, based on the calculation, was supposed to have a power of 10-15 liters. With. The engine from the Tula-200 scooter turned out to be the most suitable according to the basic data, but since neither the mountings nor the bearings satisfied it for design reasons, a new crankcase had to be cast from an aluminum alloy. This motor drives a 6-blade fan with a diameter of 600 mm. The total weight of the lifting power plant, together with mounts and an electric starter, is about 30 kg.
One of the most difficult stages turned out to be the manufacture of a skirt - a flexible cushion enclosure that wears out quickly during operation. A commercially available canvas cloth 0.75 m wide was used. complex configuration joints required about 14 m of such fabric. The strip was cut into pieces with a length equal to the length of the bead, with an allowance for a rather complex shape of the joints. After giving the required shape, the joints were sewn together. The edges of the fabric were attached to the body of the device with 2x20 duralumin strips. To increase durability, I impregnated the installed flexible fence with rubber glue, to which I added aluminum powder, which gives an elegant look. This technology makes it possible to restore a flexible fence in case of an accident and as it wears out, like building a tread. car tire... It should be emphasized that making flexible fencing is not only time-consuming, but requires special care and patience.
The assembly of the hull and the installation of the flexible fence were carried out in the upward position of the keel. Then the hull was cut out and a lifting power unit was installed in the 800x800 shaft. The control system of the installation was brought up, and now the most crucial moment has come; testing it. Will the calculations be justified, will a relatively low-power engine lift such an apparatus?
Already at medium engine speeds, the amphibian rose with me and hovered at a height of about 30 cm from the ground. The lift capacity was quite enough for a warmed-up engine to lift even four people at full speed. In the very first minutes of these tests, the features of the apparatus began to emerge. After appropriate centering, it moved freely on an air cushion in any direction, even with a small applied force. It gave the impression that he was floating on the water surface.
The success of the first test of the lift system and the hull as a whole gave me wings. Having secured the windshield, I proceeded to install the traction power plant. At first, it seemed advisable to take advantage of the extensive experience in the construction and operation of snowmobiles and install an engine with a propeller relatively large diameter on the aft deck. However, it should be taken into account that with such a "classic" version, the center of gravity of such a small apparatus would significantly increase, which would inevitably affect its driving performance and, most importantly, safety. Therefore, I decided to use two traction motors, completely similar to the lifting one, and installed them in the aft part of the amphibian, but not on the deck, but along the sides. After I fabricated and assembled a motorcycle-type control drive and installed relatively small-diameter traction propellers ("fans"), the first version of the hovercraft was ready for sea trials.
A special trailer was made to transport the amphibian behind a Zhiguli car, and in the summer of 1978 I loaded my vehicle onto it and delivered it to a meadow near a lake near Riga. This is an exciting moment. Surrounded by friends and curious people, I took the driver's seat, started the lift motor, and my new boat hung over the meadow. Started both traction motors. With an increase in the number of their revolutions, the amphibian began to move through the meadow. And then it became clear that many years of experience in driving a car and motorboat is clearly not enough. All the previous skills will not work. It is necessary to master the methods of controlling a hovercraft, which can spin endlessly in one place, like a whirligig. With increasing speed, the turning radius also increased. Any irregularities in the surface caused the apparatus to turn.
Having mastered the controls, I directed the amphibian along the gentle bank to the surface of the lake. Once above the water, the device immediately began to lose speed. The traction motors began to stall one by one, filled with spray that escaped from under the flexible air cushion railing. When passing overgrown areas of the lake, the fans sucked in reeds, the edges of their blades crumbled. When I turned off the engines, and then decided to try to start from the water, nothing came of it: my apparatus was still unable to escape from the “hole” formed by the pillow.
In general, it was a failure. However, the first defeat did not stop me. I came to the conclusion that with the existing characteristics for my air cushion vehicle, the power of the traction unit is insufficient; that is why he could not move forward when starting from the surface of the lake.
During the winter of 1979, I completely redesigned the amphibian, reducing the length of its hull to 3.70 m and its width to 1.80 m. I also designed a completely new propulsion system, completely protected from both splashes and contact with grass and reeds. To simplify the control of the installation and reduce its weight, one traction motor is used instead of two. Used power head 25-strong outboard motor Vortex-M with a completely redesigned cooling system. A closed cooling system with a volume of 1.5 liters is filled with antifreeze. The engine torque is transmitted to the “propeller” shaft of the fans located across the apparatus by means of two V-belts. Six-blade fans draw air into the chamber, from which it escapes (simultaneously cooling the engine) behind the stern through a square nozzle equipped with control flaps. From an aerodynamic point of view, such a propulsion system is apparently not very perfect, but it is quite reliable, compact and creates a thrust of about 30 kgf, which turned out to be quite sufficient.
In the middle of the summer of 1979, my apparatus was again transported to the same meadow. Having mastered the controls, I directed him to the lake. This time, finding himself above the water, he continued to move without losing speed, as if on the surface of ice. Easily, without hindrance, overcame shallows and reeds; it was especially pleasant to move over the overgrown areas of the lake, there was not even a foggy trace left. On the straight section, one of the owners with the Vikhr-M motor went on a parallel course, but soon fell behind.
The described apparatus aroused particular surprise among fans of ice fishing, when I continued testing the amphibian in winter on ice, which was covered with a layer of snow about 30 cm thick. There was real expanse on the ice! The speed could be increased to maximum. I didn't measure it exactly, but the experience of the driver suggests that it was approaching 100 km / h. At the same time, the amphibian freely overcame deep traces from motonart.
A short film was shot and shown by the Riga TV studio, after which I began to receive many requests from those wishing to build such an amphibious vehicle.
The construction of a vehicle that would allow movement both on land and on water was preceded by an acquaintance with the history of the discovery and creation of original amphibious vehicles on air cushion(WUA), study of their fundamental structure, comparison various designs and schemes.
To this end, I visited many Internet sites of enthusiasts and creators of WUAs (including foreign ones), and got acquainted with some of them on the spot. In the end, for the prototype of what was conceived boats() took the English "Hovercraft" ("soaring ship" - as the WUA is called in Great Britain), built and tested by local enthusiasts.
Our most interesting domestic machines of this type for the most part were created for law enforcement agencies, and in recent years, for commercial purposes, had large dimensions, and therefore were not suitable for amateur manufacturing.
My device is on air cushion(I call it "Aerojip") - three-seater: the pilot and passengers are arranged in a T-shaped pattern, like on a tricycle: the pilot is in front in the middle, and the passengers are next to each other, next to each other.
The machine is single-engine, with a split air flow, for which a special panel is installed in its annular channel slightly below its center. The boat-AVP consists of three main parts: a propeller-driven installation with a transmission, a fiberglass hull and a "skirt" - a flexible enclosure of the lower part of the hull, so to speak, a "pillowcase" of an air cushion. Aerojip hull.
It is double: fiberglass, consists of an inner and an outer shell. The outer shell has a rather simple configuration - it is only inclined (about 50 ° to the horizontal) sides without a bottom, flat almost across the entire width and slightly curved in the upper part of it. The bow is rounded, and the rear looks like an inclined transom.
In the upper part, along the perimeter of the outer shell, oblong holes-grooves are cut, and at the bottom, outside, a cable covering the shell is fixed in eye-bolts for attaching the lower parts of the segments to it.
The configuration of the inner shell is more complicated than the outer one, since it has almost all the elements of a small vessel (say, a boat or a boat): sides, bottom, curved gunwales, a small deck in the bow (only the upper part of the transom is missing in the stern), while as one piece.
In addition, in the middle of the cockpit along it, a separately molded tunnel with a can under the driver's seat is glued to the bottom. It houses a fuel tank and a battery, as well as a "gas" cable and a rudder control cable. In the aft part of the inner shell, a kind of hut is arranged, raised and open in front.
It serves as the base of the annular channel for the propeller, and its deck is a bulkhead as an air flow divider, part of which (supporting flow) is directed into the shaft opening, and the other part to create a propulsive thrust force.
All elements of the body: the inner and outer shells, the tunnel and the annular channel, were glued on matrices made of glass mat with a thickness of about 2 mm on polyester resin. Of course, these resins are inferior to vinylester and epoxy in adhesion, filtration rate, shrinkage, and release harmful substances when dry, but have an undeniable advantage in price - they are much cheaper, which is important.
For those who intend to use such resins, let me remind you that the room where the work is carried out must have good ventilation and a temperature of at least 22 ° C. The matrices were made in advance using a master model from the same glass mats on the same polyester resin, only the thickness of their walls was larger and amounted to 7-8 mm (for the shells of the case, about 4 mm).
Before gluing the elements, all roughness and galls were carefully removed from the working surface of the matrix, and it was covered three times with wax diluted in turpentine and polished. After that, a spray (or roller) was applied to the surface thin layer(up to 0.5 mm) gelcoat (colored varnish) of the selected yellow color.
After it had dried, the process of gluing the shell began using the following technology. First, using a roller, the wax surface of the matrix and the side of the glass mat with smaller pores are coated with resin, and then the mat is placed on the matrix and rolled until the air is completely removed from under the layer (if necessary, you can make a small cut in the mat).
In the same way, the subsequent layers of glass mats are laid to the required thickness (4-5 mm), with the installation, where necessary, of embedded parts (metal and wood). Excessive flaps at the edges are cut off when gluing "wet". It is recommended to use 2-3 layers of glass mat for the manufacture of the sides of the hull, and up to 4 layers of the bottom.
In this case, it is necessary to glue in addition all the corners, as well as the screw-in points of the fasteners. After the resin has hardened, the shell is easily removed from the matrix and processed: the edges are turned, grooves are cut, holes are drilled. To ensure the unsinkability of the "Aerodzhip", pieces of foam plastic (for example, furniture) are glued to the inner shell, leaving only free channels for the passage of air along the entire perimeter.
The pieces of foam are glued together with resin, and are attached to the inner shell with strips of glass mat, also oiled with resin. After the outer and inner shells are made separately, they are docked, fastened with clamps and self-tapping screws, and then joined (glued) along the perimeter with strips of the same glass mat coated with polyester resin, 40-50 mm wide, from which the shells themselves were made.
After that, the body is left until the resin has completely polymerized. A day later, a duralumin strip with a section of 30x2 mm is attached to the upper junction of the shells along the perimeter with rivets, setting it vertically (the tongues of the segments are fixed on it). Wooden runners with dimensions of 1500x90x20 mm (length x width x height) are glued to the bottom of the bottom at a distance of 160 mm from the edge.
One layer of glass mat is glued on top of the runners. In the same way, only from the inside of the shell, in the aft part of the cockpit, is a base made of a wooden plate for the engine. It is worth noting that using the same technology as the outer and inner shells were made, smaller elements were also glued: the inner and outer shell of the diffuser, rudders, gas tank, engine cover, wind damper, tunnel and driver's seat.
For those who are just starting to work with fiberglass, I recommend preparing the production boats precisely from these small elements. The total mass of the fiberglass body with diffuser and rudders is about 80 kg.
Of course, the manufacture of such a hull can also be entrusted to specialist firms that produce fiberglass boats and boats. Fortunately, there are many of them in Russia, and the costs will be commensurate. However, in the process self-made it will be possible to gain the necessary experience and the ability to model and create various elements and structures from fiberglass in the future. Propeller-driven installation.
It includes an engine, a propeller and a transmission that transfers torque from the first to the second. The engine is used by BRIGGS & STATTION, produced in Japan under an American license: 2-cylinder, V-shaped, four-stroke, 31 hp. at 3600 rpm. Its guaranteed service life is 600 thousand hours.
Starting is carried out by an electric starter, from the battery, and the work of the spark plugs is from a magneto. The engine is mounted on the bottom of the Aerojip body, and the propeller hub axis is fixed at both ends on brackets in the center of the diffuser, raised above the body. The transmission of torque from the motor output shaft to the hub is carried out by a toothed belt. The driven and driving pulleys, like the belt, are toothed.
Although the mass of the engine is not so great (about 56 kg), its location on the bottom significantly lowers the center of gravity of the boat, which has a positive effect on the stability and maneuverability of the vehicle, especially this one - "aeronautical".
Exhaust gas is led out into the lower air stream. Instead of the established Japanese one, you can also use suitable domestic engines, for example, from snowmobiles "Buran", "Lynx" and others. By the way, engines with a capacity of about 22 liters are quite suitable for a one- or two-seater WUA. With.
The propeller is six-bladed, with a fixed pitch (set on land by the angle of attack) of the blades. The annular channel of the propeller should also be attributed to an integral part of the propeller-driven installation, although its base (lower sector) is made integral with the inner shell of the body.
The annular channel, like the body, is also composite, glued from the outer and inner shells. Just in the place where the lower sector joins it with the upper one, a fiberglass dividing panel is arranged: it divides the air flow created by the propeller (and, on the contrary, connects the walls of the lower sector along a chord).
The engine, located at the transom in the cockpit (behind the back of the passenger seat), is closed from above with a fiberglass hood, and the propeller, in addition to the diffuser, is also a wire grille in front. Soft elastic "Aerodjip" guard (skirt) consists of separate, but identical segments, cut and sewn from dense lightweight fabric.
It is desirable that the fabric is water-repellent, does not harden in the cold and does not allow air to pass through. I used Finnish Vinyplan material, but a domestic fabric such as percale is quite suitable. The pattern of the segment is simple, and you can even sew it manually. Each segment is attached to the body as follows.
The tongue is thrown over the side vertical strip, with an overlap of 1.5 cm; on it is the tongue of the adjacent segment, and both of them, in the place of the overlap, are fixed on the bar with a special clip of the "crocodile" type, only without teeth. And so along the entire perimeter of the "Aerodzip". For reliability, you can also put the clip in the middle of the tongue.
The two lower corners of the segment with the help of nylon clamps are suspended freely on a cable that wraps around the lower part of the outer shell of the body. Such a composite skirt design allows you to easily replace a failed segment, which will take 5-10 minutes. To the point it will be said that the structure turns out to be efficient in case of failure of up to 7% of the segments. In total, they can be placed on a skirt up to 60 pieces.
The principle of movement of the "Aerojip" is as follows. After starting the engine and idling, the machine remains in place. As the number of revolutions increases, the propeller begins to drive a more powerful air flow. Part of it (large) creates propulsive force and propels the boat forward.
The other part of the flow goes under the dividing panel into the side air ducts of the body (free space between the shells to the very nose), and then through the holes-grooves in the outer shell evenly enters the segments.
This flow, simultaneously with the start of movement, creates an air cushion under the bottom, raising the vehicle above the underlying surface (whether it is soil, snow or water) by several centimeters. Rotation of the "Aerojip" is carried out by two rudders, deflecting the "forward" air flow to the side.
The rudders are controlled from a motorcycle-type double-arm steering column, through a Bowden cable running on the starboard side between the shells to one of the rudders. Another rudder is connected to the first rigid rod. On the left handle of the two-armed lever, the carburetor throttle control lever is also fixed (analogue of the throttle handle).
For operation hovercraft it must be registered with your local state inspection on small boats(GIMS) and get a ship ticket. To obtain a certificate for the right to drive a boat, you must also pass a training course on how to operate a small boat. However, even on these courses, there are still far from everywhere instructors for piloting hovercraft.
Therefore, each pilot has to master the management of the WUA independently, literally bit by bit, gaining the appropriate experience.
Air cushion boat "Aerodzhip": 1-segment (dense fabric); 2-mooring cleat (3 pcs.); 3-wind visor; 4-side segment fastening strip; 5-handle (2 pcs.); 6-propeller guard; 7-ring channel; 8-rudder (2 pcs.); 9-steering wheel control lever; 10-door access to the gas tank and battery; 11-seat of the pilot; 12-passenger sofa; 13-engine casing; 14-engine; 15-outer shell; 16-filler (foam); 17-inner shell; 18-split panel; 19-propeller; 20-propeller hub; 21-drive toothed belt; 22-knot for fixing the lower part of the segment
The theoretical drawing of the body: 1 - inner shell; 2-outer sheath
The transmission diagram of the propeller-driven installation: 1 - the output shaft of the engine; 2-drive toothed pulley; 3 - toothed belt; 4-driven toothed pulley; 5 - nut; 6-distance sleeves; 7-bearing; 8-axis; 9-hub; 10-bearing; 11-distance sleeve; 12-support; 13-propeller
Steering column: 1-handle; 2-arm lever; 3-rack; 4-bipod (see photo)
Steering diagram: 1-steering column; 2-Bowden cable, 3-unit for attaching the braid to the body (2 pcs.); 4-bearing (5 pcs.); 5-steering panel (2 pcs.); 6-arm arm-bracket (2 pcs.); 7-tie rod steering panels (see photo)
Flexible fencing segment: 1 - walls; 2-cover with tongue
Unsatisfactory network condition highways and practically complete absence road infrastructure on most regional highways makes it necessary to look for vehicles operating on different physical principles. One such means is a hovercraft capable of moving people and goods off-road.
Hovercraft carrying sonorous technical term"Hovercraft", differs from traditional models of boats and cars not only in the ability to move on any surface (pond, field, swamp, etc.), but also in the ability to develop a decent speed. The only requirement for such a "road" is that it should be more or less flat and relatively soft.
However, the use of an air cushion by an all-terrain boat requires rather serious energy costs, which in turn entails a significant increase in fuel consumption. The operation of hovercraft (AHC) is based on a combination of the following physical principles:
- Low specific pressure of the SVP on the soil or water surface.
- High speed of movement.
This factor has a fairly simple and logical explanation. The area of the contact surfaces (the bottom of the apparatus and, for example, the soil) corresponds to or exceeds the area of the SVP. Speaking technical language, the vehicle dynamically generates the required thrust.
Excessive pressure created in a special device lifts the machine from the support to a height of 100-150 mm. It is this cushion of air that interrupts the mechanical contact of the surfaces and minimizes the resistance to the translational movement of the hovercraft in the horizontal plane.
Despite the ability to move quickly and, most importantly, economically, the scope of the hovercraft on the surface of the earth is significantly limited. Asphalt areas, hard rocks with the presence of industrial debris or hard stones are absolutely unsuitable for it, since the risk of damage to the main element of the SVP, the bottom of the pillow, significantly increases.
Thus, the optimal hovercraft route can be considered one where you need to swim a lot and go a little in places. In some countries, such as Canada, hovercraft are used by rescuers. According to some reports, devices of this design are in service with the armies of some NATO member countries.
Why is there a desire to make a DIY hovercraft? There are several reasons:
That is why SVPs were not widely used. Indeed, an ATV or snowmobile can be purchased as an expensive toy. Another option is to make a car boat yourself.
When choosing a working scheme, it is necessary to decide on the design of the case that best suits the given technical specifications... Note that it is quite possible to create a do-it-yourself SVP with assembly drawings of home-made elements.
Specialized resources abound with ready-made drawings of homemade hovercraft. The analysis of practical tests shows that the most successful option, satisfying the conditions arising when moving on water and ground, are cushions formed by the chamber method.
When choosing a material for the main structural element of a hovercraft - the body, consider several important criteria. Firstly, it is simplicity and ease of processing. Secondly, a small specific gravity material. It is this parameter that ensures that the SVP belongs to the category of "amphibians", that is, there is no risk of flooding in the event of an emergency stop of the vessel.
As a rule, 4 mm plywood is used for the manufacture of the hull, and the superstructures are made of foam. This significantly reduces the dead weight of the structure. After pasting the outer surfaces with penoplex and subsequent painting, the model acquires its original features appearance original. For the glazing of the cabin, polymer materials are used, and the rest of the elements are bent out of the wire.
Making a so-called skirt will require a dense waterproof fabric made of polymer fiber. After cutting, the parts are sewn with a double tight seam, and gluing is done using waterproof glue... This provides not only a high degree of structural reliability, but also allows you to hide the assembly joints from prying eyes.
The design of the power plant assumes the presence of two engines: marching and pumping. They are equipped with brushless electric motors and two-blade propellers. A special regulator carries out the process of managing them.
The supply voltage is supplied from two rechargeable batteries, the total capacity of which is 3,000 milliamperes per hour. At the maximum charge level, the hovercraft can be operated for 25-30 minutes.
Attention, only TODAY!
The prototype of the presented amphibious vehicle was an air-cushion vehicle (WUA) called "Aerojip", the publication of which was in the magazine. Like the previous apparatus, the new machine is a single-engine, single-rotor with a distributed air flow. This model is also three-seater, with a T-shaped arrangement of the pilot and passengers: the pilot is in front in the middle, and the passengers are on the sides, behind. Although nothing prevents the fourth passenger from settling behind the driver's back - the length of the seat and the power of the propeller installation are quite enough.
New car, except for improved technical characteristics, has a number design features and even innovations that increase its operational reliability and survivability - after all, an amphibian is a waterfowl "bird". And I call it “bird” because it still moves through the air both above water and above the ground.
Structurally, the new machine consists of four main parts: a fiberglass body, a pneumatic cylinder, a flexible fence (skirt) and a propeller-driven installation.
Leading a story about new car, you will inevitably have to repeat yourself - after all, the designs are in many ways similar.
Amphibious body identical to the prototype both in size and design - fiberglass, double, volumetric, consists of inner and outer shells. It is also worth noting here that the holes in the inner shell in the new device are now located not at the upper edge of the sides, but approximately in the middle between it and the bottom edge, which ensures a faster and more stable creation of an air cushion. The holes themselves are now not oblong, but round, with a diameter of 90 mm. There are about 40 of them and they are evenly spaced along the sides and in front.
Each shell was glued in its own matrix (used from the previous design) from two or three layers of fiberglass (and the bottom - from four layers) on a polyester binder. Of course, these resins are inferior to vinyl ether and epoxy resins in adhesion, filtration level, shrinkage, and release of harmful substances during drying, but they have an undeniable price advantage - they are much cheaper, which is important. For those who intend to use such resins, let me remind you that the room where the work is carried out must have good ventilation and a temperature of at least + 22 ° C.
1 - segment (set of 60 pcs.); 2 - balloon; 3 - mooring cleat (3 pcs.); 4 - wind visor; 5 - handrail (2 pcs.); 6 - mesh protection of the propeller; 7 - the outer part of the annular channel; 8 - rudder (2 pcs.); 9 - steering wheel control lever; 10 - hatch in the tunnel for access to the fuel tank and battery; 11 - pilot's seat; 12 - passenger sofa; 13 - engine casing; 14 - paddle (2 pcs.); 15 - muffler; 16 - filler (foam); 17 - the inner part of the annular channel; 18 - lantern navigation light; 19 - propeller; 20 - propeller bushing; 21 - drive toothed belt; 22 - unit for attaching the cylinder to the body; 23 - unit for attaching the segment to the body; 24 - engine mounted on a motor mount; 25 - inner shell of the body; 26 - filler (foam); 27 - outer shell of the body; 28 - dividing panel of the forced air flow
The matrices were made in advance according to the master model from the same glass mat on the same polyester resin, only the thickness of their walls was larger and amounted to 7-8 mm (for the shells of the case - about 4 mm). Before vykpeyka elements from the working surface of the matrix were carefully removed all roughness and seizure, and it was covered three times with wax diluted in turpentine and polished. After that, a thin layer (up to 0.5 mm) of red gelcoat (colored varnish) was applied to the surface with a spray (or roller).
After it had dried, the process of gluing the shell began using the following technology. First, using a roller, the wax surface of the matrix and one side of the stekomat (with smaller pores) are coated with resin, and then the mat is placed on the matrix and rolled until the air is completely removed from under the layer (if necessary, you can make a small cut in the mat). In the same way, the subsequent layers of glass mats are laid to the required thickness (3-4 mm), with the installation, where necessary, of embedded parts (metal and wood). Excessive flaps at the edges were cut off during wet-gluing.
a - outer shell;
b - inner shell;
1 - ski (tree);
2 - sub-engine plate (wood)
After the outer and inner shells were made separately, they were docked, fastened with clamps and self-tapping screws, and then glued along the perimeter with strips of the same glass mat coated with polyester resin, 40-50 mm wide, from which the shells themselves were made. After the shells were attached to the edge with petal rivets, a vertical side strip made of a 2-mm duralumin strip with a width of at least 35 mm was attached along the perimeter.
Additionally, pieces of resin-impregnated fiberglass should be carefully glued to all corners and screwing points of fasteners. The outer shell is coated on top with a gelcoat - a polyester resin with acrylic additives and wax, which gives shine and water resistance.
It is worth noting that using the same technology (the outer and inner shells were made using it), smaller elements were also glued: the inner and outer shell of the diffuser, rudders, engine casing, wind deflector, tunnel and driver's seat. A gas tank (industrial from Italy) of 12.5 liters is inserted into the body, into the console, before fastening the lower and upper parts of the bodies.
an inner shell of the housing with air outlets to create an air cushion; above the holes - a row of cable clips for engaging the ends of the skirt segment of the skirt; two wooden skis are glued to the bottom
For those who are just starting to work with fiberglass, I recommend starting the manufacture of a boat with these small elements. The total mass of the fiberglass body with skis and an aluminum alloy strip, diffuser and rudders is from 80 to 95 kg.
The space between the shells serves as an air duct along the perimeter of the vehicle from the stern on both sides to the bow. The top and bottom of this space are filled with construction foam, which provides optimal section air channels and additional buoyancy (and, accordingly, survivability) of the apparatus. The pieces of foam were glued together with the same polyester binder, and to the shells they were glued with strips of fiberglass, also impregnated with resin. Further, the air from the air channels goes out through evenly spaced holes with a diameter of 90 mm in the outer shell, "rests" on the segments of the skirt and creates an air cushion under the apparatus.
To protect it from damage, a pair of longitudinal skis made of wooden bars are glued to the bottom of the outer shell of the hull, and a sub-engine wooden plate is glued to the aft part of the cockpit (that is, from the inside).
Balloon... The new model of the hovercraft has almost twice the displacement (350 - 370 kg) than the previous one. This was achieved by installing an inflatable balloon between the body and the segments of the flexible fence (skirt). The cylinder is glued from polyvinyl chloride film based on polyvinyl chloride (PVC) material Finnish production with a density of 750 g / m 2 according to the shape of the body in the plan. The material has been tested on large industrial hovercraft such as Hius, Pegasus, Mars. To increase survivability, the cylinder can consist of several compartments (in this case, three, each with its own filling valve). The compartments, in turn, can be divided in half lengthwise by longitudinal partitions (but this version of them is still only in the project). With this design, a punched compartment (or even two) will allow you to continue along the route, and even more so to get to the coast for repairs. For economical cutting of material, the cylinder is divided into four sections: bow, two boring. Each section, in turn, is glued from two parts (halves) of the shell: the lower and the upper - their patterns are mirrored. In this version of the cylinder, the compartments and sections do not coincide.
a - outer shell; b - inner shell;
1 - bow section; 2 - side section (2 pcs.); 3 - aft section; 4 - partition (3 pcs.); 5 - valves (3 pcs.); 6 - lyctros; 7 - apron
On the top of the balloon is glued "lyktros" - a strip of double-folded material Vinyplan 6545 "Arctic", with a braided nylon cord embedded along the fold, impregnated with glue "900I". "Liktros" is applied to the side plate, and with the help of plastic bolts the balloon is attached to an aluminum strip fixed to the body. The same strip (only without the inserted cord) is glued to the cylinder from the bottom to the front ("half past seven"), the so-called "apron" - to which the upper parts of the segments (tongues) of the flexible fence are tied. Later, a rubber bumper was glued to the front of the cylinder.
Soft elastic fence"Aerojip" (skirt) consists of separate, but identical elements - segments, cut and sewn from dense lightweight fabric or film material. It is desirable that the fabric is water-repellent, does not harden in the cold and does not allow air to pass through.
I used again the material Vinyplan 4126, only with a lower density (240 g / m2), but the domestic fabric of the percale type is quite suitable.
The segments are slightly smaller than on the “balloonless” model. The pattern of the segment is simple, and you can sew it yourself even manually, or weld it with high frequency currents (TVS).
The segments are tied with the cover tongue to the cylinder lid (two - with one end, while the nodules are inside under the skirt) along the entire perimeter of the "Aeroamphibia". The two lower corners of the segment with the help of nylon construction clamps are suspended freely from a steel cable with a diameter of 2 - 2.5 mm, wrapping around the lower part of the inner shell of the body. In total, the skirt accommodates up to 60 segments. A steel cable with a diameter of 2.5 mm is attached to the body by means of clips, which in turn are attracted to the inner shell by means of petal rivets.
1 - scarf (material "Viniplan 4126"); 2 - tongue (material "Viniplan 4126"); 3 - overlay (fabric "Arctic")
Such fastening of the skirt segments is not much longer than the replacement time for a failed flexible barrier element, in comparison with the previous design, when each was fastened separately. But as practice has shown, the skirt turns out to be efficient even in case of failure of up to 10% of the segments and their frequent replacement is not required.
1 - outer shell of the body; 2 - inner shell of the body; 3- strip (fiberglass) 4 - strip (duralumin, strip 30x2); 5 - self-tapping screw; 6 - balloon lyktros; 7 - plastic bolt; 8 - balloon; 9 - the apron of the cylinder; 10 - segment; 11 - lacing; 12 - clip; 13-clamp (plastic); 14-rope d2.5; 15-hole rivet; 16-grommet
The propeller-driven installation consists of an engine, a six-blade propeller (fan) and a transmission.
Engine- RMZ-500 (analogue of Rotax 503) from the Taiga snowmobile. Produced by JSC Russian Mechanics under the license of the Austrian company Rotax. The motor is two-stroke, with a petal inlet valve and forced air cooling. It has established itself as a reliable, powerful enough (about 50 hp) and not heavy (about 37 kg), and most importantly, a relatively inexpensive unit. Fuel - gasoline of the AI-92 brand mixed with oil for two-stroke engines (for example, the domestic MGD-14M). Average consumption fuel - 9 - 10 l / h. The engine is mounted in the aft part of the apparatus, on a motor frame attached to the bottom of the hull (or rather, to the sub-engine wooden plate). The motor mount has become taller. This is done for the convenience of cleaning the aft part of the cockpit from snow and ice, which get there through the sides and accumulate there, and freeze when stopped.
1 - motor output shaft; 2 - a leading toothed pulley (32 teeth); 3 - toothed belt; 4 - driven gear pulley; 5 - nut М20 for fastening the axle; 6 - spacer sleeves (3 pcs.); 7 - bearing (2 pcs.); 8 - axis; 9 - screw sleeve; 10 - rear strut support; 11 - front overmotor support; 12 - front strut support-biped (not shown in the drawing, see photo); 13 - outer cheek; 14 - inner cheek
The propeller is six-bladed, with a fixed pitch, with a diameter of 900 mm. (There was an attempt to install two five-blade coaxial propellers, but it was unsuccessful). The screw sleeve is die-cast aluminum. Blades - fiberglass, coated with gelcoat. The axis of the propeller hub was lengthened, although the previous bearings 6304 remained on it. The axle was mounted on a rack above the engine and fixed here with two spacers: a two-beam at the front and a three-beam at the rear. In front of the propeller there is a mesh guard railing, and at the back there are air rudder feathers.
The transmission of torque (rotation) from the engine output shaft to the propeller hub is carried out through a toothed belt with a gear ratio of 1: 2.25 (the driving pulley has 32 teeth, and the driven pulley has 72 teeth).
The air flow from the propeller is distributed by a partition in the annular channel into two unequal parts (approximately 1: 3). A smaller part of it goes under the bottom of the hull to create an air cushion, and a large part goes to the formation of propulsive force (thrust) for movement. A few words about the features of driving amphibians, specifically - about the beginning of the movement. When the engine is idling, the apparatus remains stationary. With an increase in the number of its revolutions, the amphibian first rises above the supporting surface, and then begins to move forward at revolutions from 3200 - 3500 per minute. At this moment, it is important, especially when starting off from the ground, that the pilot first lifts the rear of the aircraft: then the aft segments will not catch on to anything, and the front ones will slide over bumps and obstacles.
1 - base (steel sheet s6, 2 pcs.); 2 - portal rack (steel sheet s4,2 pcs.); 3 - jumper (steel sheet s10, 2 pcs.)
Aerodynamic control (changing the direction of movement) is carried out by aerodynamic rudders, hingedly attached to the annular channel. The steering is deflected by means of a two-arm lever (motorcycle-type steering wheel) through an Italian Bowden cable going to one of the planes of the aerodynamic steering wheel. Another plane is connected to the first rigid rod. On the left handle of the lever, there is a lever for controlling the throttle of the carburetor or the trigger from the Taiga snowmobile.
1 - steering wheel; 2 - Bowden cable; 3 - unit for attaching the braid to the body (2 pcs.); 4 - Bowden cable sheath; 5 - steering panel; 6 - lever; 7 - thrust (the rocking chair is conventionally not shown); 8 - bearing (4 pcs.)
Braking is carried out by “throttle release”. At the same time, the air cushion disappears and the apparatus lies on the water with its body (or with skis - on snow or ground) and stops due to friction.
Electrical equipment and devices... The device is equipped with a rechargeable battery, a tachometer with an hour meter, a voltmeter, an engine head temperature indicator, halogen headlights, a button and a check for turning off the ignition on the steering wheel, etc. The engine is started by an electric starter. Installation of any other devices is possible.
The amphibious boat was named Rybak-360. It passed sea trials on the Volga: in 2010, at the rally of the Velkhod company in the village of Emmaus near Tver, in Nizhny Novgorod... At the request of Moskomsport, he took part in demonstration performances at the holiday dedicated to the Day of the Navy in Moscow on the Grebnoy Canal.
Technical data of "Aeroamphibia":
Overall dimensions, mm:
length ………………………………………………………………… ..3950
width ……………………………………………………………… ..2400
height ………………………………………………………………… .1380
Engine power, HP …………………………………………… .52
Weight, kg …………………………………………………………………… .150
Carrying capacity, kg ……………………………………………… .370
Fuel capacity, l ………………………………………………………… .12
Fuel consumption, l / h …………………………………………… ..9 - 10
Overcoming obstacles:
rise, hail ……………………………………………………………… .20
wave, m …………………………………………………………………… 0.5
Cruising speed, km / h:
by water ……………………………………………………………………… .50
on the ground …………………………………………………………………… 54
on ice ……………………………………………………………………… .60
M. YAGUBOV Honorary Inventor of Moscow
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