In the vastness of our country, lovers of active recreation do not miss the opportunity to ensure comfortable off-road travel, including water obstacles, at any time of the year. And if you won’t surprise anyone with a snowmobile, jet ski and aerobot, the use of military equipment attracts attention. The focus of this article is a boat on air cushion, his technical specifications, possibilities of use in peacetime, user reviews and a brief overview of prices for this type of transport.
Operating principle
A hovercraft, thanks to the laws of aerodynamics, uses the air flow created by the engine not only for propulsion, but also to reduce friction. An air cushion is a layer of compressed air under the bottom of a vehicle, which is held in place by the gravity of the vessel. Excessive air pressure leads to its release in the area of contact between the bottom of the vessel and the surface of the earth or water. At the moment of bleeding off excess air, the friction force between the bottom of the vehicle and the surface of the earth is practically absent - this makes it possible not only to move the vessel using an aeroengine, but also to control it freely.
In addition to static work aimed at overcoming friction, the propulsion-discharge system also creates dynamic work, forcing the vessel to move. To do this, a huge fan is installed on the boat’s hull, which accelerates the boat with a powerful air flow. The ceilings located behind the fan allow you to control the air flow, regulating the direction of traffic.
Technical capabilities
The technical characteristics of hovercrafts will not allow lovers of active recreation to pass by indifferently.
- Any surface for movement. A body of water with a wave height of up to 25 cm, ice or snow cover is the native element for the vessel. You can travel on grass, sand, swamp, gravel or asphalt, but in such cases you need to be prepared for rapid wear of the flexible air cushion fence.
- Load capacity. If we are talking about civil ships, then the carrying capacity, including passengers, is approximately 1000-1500 kilograms. To a greater extent, this parameter depends on the engine power.
- Travel speed and fuel consumption. The standard is considered to be a fuel consumption of 20 liters per hour at a cruising speed of 60 km/h. Maximum indicators should not deviate from the arithmetic progression. That is, a boat speed of 120 km/h will double fuel consumption, but no more.
Limitations of Use
Small, medium or large hovercraft have a number of limitations that all buyers without exception need to know.
- If the wave height is more than 30 cm on the water surface, the movement of the boat will be difficult and can lead to flooding, since jerks and impacts on the wave crests reduce the air pressure under the flexible fence, plunging the boat half into the water.
- Dense and tall vegetation limits the flexible fencing's close contact with the ground, which can also make movement difficult.
- Hard obstacles over 35 cm (driftwood, stumps, stones) not only reduce the pressure under the bottom of the vessel, but can also damage the flexible fencing. Although repairing boats on site is not a problem if you have an awl and wire, it is, however, an extra time investment.
Where did the interest come from?
In the 20th century, river and sea hovercraft were considered the best transport for walking on the water surface. Enormous speed, excellent maneuverability and high safety attracted not only tourists, but also the local population, who moved to suburban areas and back along the seas, lakes and rivers of our huge country. But the attention of hunters and fishermen was attracted by the landing boat after the screening of the film “Retaliation” at the end of the twentieth century. It was then that the era of small hovercraft arose, because the film clearly presented all the technical capabilities of this type of transport, for which there are practically no barriers.
Landing boats are still in service in many countries around the world. The peace and tranquility of Russians is protected by the world's largest hovercraft called the Zubr. It won’t be much of a problem for him to cross the entire Black Sea with a couple of tanks and a dozen armored personnel carriers on board. In addition to transporting cargo, the ship has cruise missiles on board, which makes it a combat unit in wartime.
Young technician - the beginning of all beginnings
Reproducing the landing craft in sizes acceptable for transportation by the Russian Kulibin did not present any particular problems. By conducting tests and presenting the amphibian production technology to the country's scientific and technical publications, craftsmen made it possible for military technologies to serve for peaceful purposes. If you open any technical journal of that time, in the photo you can find not only motor boats with an air cushion or with a hard bottom. To overcome land and water expanses, masters came up with all sorts of symbioses of automobile transport and floating vehicles, vaguely reminiscent of BRDM.
However, all of them remained only on paper, which cannot be said about the most popular transport in the world, for which there are no barriers - the hovercraft. In the media even now you can find many detailed instructions, confirmed by photos and videos, on the production of watercraft with our own hands from scratch. However, professionals recommend refraining from such proposals, because the SVP is considered dangerous.
Above are only the stars
The Pegasus series boat is recognized as the best hovercraft. First of all, it differs from its competitors in its ability to be used at any time of the year. All new boats have an enclosed interior. It is made with a heating system and allows you to maintain comfortable conditions even in thirty-degree frost. In the summer heat, the cabin can be easily transformed, allowing for improved circulation of fresh air. Depending on the modification, the craft can carry on board from 5 to 8 people with 350-500 kg of equipment.
If we take into account low fuel consumption and good range and speed, we can conclude that this is the best boat. The price of such a device can be confusing ordinary person- 30,000 conventional units. However, if you add up the cost of the equipment taken together - a motor boat, an ATV and a snowmobile, it becomes clear that the hovercraft has a very attractive price.
If you are interested in the corporate segment, then the ship of the Neptune series is recognized as the leader here. Having many modifications at its disposal, the device is primarily positioned as a cross-country vehicle for transporting passengers.
Domestic alternative
In addition to "Pegasus" on Russian market The hovercraft “Mars”, “Neoteric”, “Sagittarius”, “Mirage”, as well as sea boats for transporting up to 15 people of the “Aerojet” series, have proven themselves well. All of them belong to the tourist class, which is why they have a number of restrictions, primarily regarding operating modes. For example, the Mirage ship can be used all year round, including severe frosts, but its movement over waves and uneven surfaces is limited due to some design features. But the baby “Neoteric” is able to go where no human has gone before, not to mention the low fuel consumption (5 liters per hour) and the enormous speed of the boat. But it has big problems with carrying capacity and operation at subzero temperatures.
An air-cushioned vehicle called “Bug” is considered a miracle of Russian industry. After viewing the hovercraft in the photo, no one will dare to call it a watercraft. It looks more like a hovercraft. The small-sized two-seater device shows high cross-country ability on different surfaces and at large angles.
SVP for fun
Judging by numerous reviews from owners, the Tornado hovercraft has gained great popularity in Russia. It was manufactured by the Ukrainian manufacturer Artel LLC at the Nikolaev shipyard. Initially, the boat is positioned as a watercraft for entertainment and cultural recreation. It is enough to see a photo of the boat to be convinced that it is unsuitable for fishing or hunting. Small dimensions and low load capacity enable the hovercraft to violate all the laws of physics and aerodynamics, both in speed and maneuverability, and in passing all kinds of obstacles. Why did he interest the Russian buyer?
- Low price. For just ten thousand conventional units you can buy yourself a universal vehicle.
- Possibility of modernization. The SVP boat can be perfectly converted for both hunting and fishing for two people.
- Spare parts Russian production. In addition to the RMZ-550 engine, all components can be found on the domestic market.
The inexpensive but low-power hovercraft Hov Pod SPX, presented by the English plant, is the most popular watercraft in Europe. It is also in service in two dozen countries around the world and is in demand in UN rescue missions. On the retail market, the boat is positioned as transport for the whole family - fishing, tourism, active recreation, picnics - all this is within its control. The manufacturer claims that simplicity, convenience and safety are the main attributes of this vessel, and a child can be trusted to operate the boat.
English high-tech devices and mechanisms have always been distinguished from their competitors by their impeccability. The Hov Pod SPX hovercraft is made of a unique composite material, which is used to make fences in Formula 1. The steering is made of Teleflex stainless steel. The base of the body, the engine protection, and all metal components in the body structure are chrome-plated. Thus, the manufacturer makes it clear to its customers that boat trips are not prohibited.
Need of government agencies
In addition to active recreation and entertainment, hovercraft have found their purpose in the Ministry of Internal Affairs and Emergency Situations. For example, the Sever watercraft is used by transport police to search for and detain crime suspects. The hovercraft not only shows excellent speed characteristics (150 km/h on water), but is also capable of overcoming long slopes of up to 30 degrees. This vessel was noticed in service with the fishery inspectorate. Excellent tactical and technical characteristics will always attract attention.
For the repair of bridges and structures, maintenance of oil production platforms, carrying out all kinds of diving work, as well as if it is necessary to repair boats, yachts and cargo ships anchored in the roadstead, the Shelf series hovercraft is used. Huge engine power and large sizes allow you to place up to two tons of cargo on the ship without taking into account 20 workers. 360 degree rotation without displacement allows you to easily maneuver in any hard-to-reach place.
Japanese engines
Mostly all hovercraft are equipped with engines from Japanese automotive giants Honda and Subaru. This choice is not accidental. Unlike usual motor boats, where the priority is the number of revolutions per minute of the propeller shaft, high power is more important for boats with a propulsion system. Naturally, fuel efficiency is always a priority for any owner. Two-liter and 130-horsepower Honda D15B and Subaru EJ20 engines have found application on air-cushioned boats.
And if their choice was initially justified high performance and durability during operation, then at the moment the popularity lies in the possibilities of modernization. Craftsmen not only increased engine power to 150 horsepower, but also made them significantly easier by replacing some components. The result is a very fast hovercraft.
Legality of use
A hovercraft is classified as a small craft, which means it is subject to registration with the state inspectorate with the appropriate name. To operate a watercraft, it must also be registered and receive special licenses. These procedures are very simple and do not cause any problems. The only thing that can cause trouble is getting a medical certificate to test your license. After all, it’s not every day that doctors see owners of small boats. Judging by the numerous reviews of SVP owners, when passing the commission, it is recommended to talk about the usual test for driving a motor vehicle. Thus, the owner will significantly speed up the passage of the commission and save himself from questions and jokes from the medical staff.
In conclusion
As it turns out, the hovercraft market is not empty. Large quantity models of both domestic and imported production have affordable price and open up a wide range of possibilities. When making a choice among models, you first need to outline the areas of use - walking, entertainment, travel, hunting, fishing. After this, it is recommended to decide in what season the boat will be used. The price of the watercraft greatly depends on this choice.
You need to decide on the number of passengers and carrying capacity. But the choice of engine, fuel system and steering does not play a special role, since most devices have very similar characteristics, which will have little effect on the price. Unless a potential buyer decides to give his preference to an English car, which has a 65-horsepower engine and is not capable of accelerating over 70 km/h.
Hovercraft allows you to move on water and on land. In this article we will look at how to make it yourself.
Hovercraft - what is it?
One of the ways to combine a car and a boat is a hovercraft, which has good maneuverability and high speed through the water due to the fact that its body does not sink under the water, but, as it were, glides along its surface.
This method allows you to move economically and quickly, since the sliding friction force and the resistance force water masses- these are, as they say, two big differences.
But, unfortunately, despite all the advantages of a hovercraft, its scope of application on earth is limited - it cannot move on any surface, but only on a fairly soft one, such as sand or soil. Asphalt and hard rocks with sharp stones and industrial debris will simply tear up the bottom of the ship, rendering the air cushion unusable, and it is thanks to it that the hovercraft moves.
Therefore, hovercrafts are used mainly where you need to swim a lot and drive a little, otherwise amphibious vehicles with wheels are used. SVPs are not widely used today, but in some countries rescuers work on them, for example, in Canada, and there is also evidence that they are in service with NATO.
Should you buy a hovercraft or make it yourself?
Hovercrafts 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 under you, although such cases have happened, but still the probability here is lower than with a homemade one.
In addition, manufacturers mainly sell “professional” hovercraft for fishermen, hunters, and all kinds of services. Amateur vessels can be found extremely rarely, and they are mostly handmade products, due, again, to their low popularity among the people.
Why hovercrafts haven't gained more love
Main reasons:
- High price and expensive maintenance. The fact is that the parts and functional units of the hovercraft wear out very quickly and require replacement, and the purchase and installation also cost a lot of money. Therefore, only a rich person can afford it, but even for him, it is very inconvenient to take a broken ship to a repair shop every time, since there are only a few such workshops, and they are mainly located only in major cities. Therefore, as a toy, it is more profitable to buy, for example, an ATV or a jet ski.
- Because of the screws, they are very noisy, so you can only ride with headphones.
- You cannot sail or ride against the wind, as the speed is greatly reduced.
Amateur hovercraft were and remain only a way to demonstrate their design abilities for those who can service and repair them themselves.
DIY process
Making a good hovercraft is not easy, but if you have thought about it, then most likely you either have 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 on the first test drive.
So, you should start with a drawing. Develop the design of your hovercraft. How do you want it to be? Rounded, like the Soviet MI-28 helicopter or angular, like the American Alligator? Should it be streamlined like a Ferrari, or Zaporozhets-shaped? When you answer these questions for yourself, start creating a drawing.
How to catch more fish?
Over 13 years of active fishing, I have found many ways to improve the bite. And here are the most effective:- Bite activator. Attracts fish in cold and warm water with the help of pheromones included in the composition and stimulates its appetite. It's a pity that Rosprirodnadzor wants to ban its sale.
- More sensitive gear. Read the appropriate manuals for the specific type of gear on the pages of my website.
- Lures based pheromones.
The figure shows a sketch of the hovercraft used by the Canadian Rescue Service.
Vessel technical characteristics
An average home-made hovercraft can reach a fairly high speed - exactly what speed depends on the weight of the 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.
Regarding the load capacity, we can say that the single-seat hovercraft model proposed here is capable of supporting a driver weighing 100-120 kg.
You will have to get used to the controls, since it is significantly different from a regular boat, firstly, because there are completely different speeds, and secondly, it is fundamentally different ways movement.
The faster the hovercraft moves, the more it skids when turning, so you need to lean a little to the side. By the way, if you get used to it, you can “drift” well on a hovercraft.
Required materials
All you need is plywood, foam and special set a kit from Universal Hovercraft, designed specifically for self-taught engineers, containing everything you need.
Insulation, screws, fabric for the air cushion, epoxy, glue and more - all this is already included in the ready-made kit, which you can order on their official website for $ 500, and in addition there will be several options for the plan with drawings.
Case manufacturing
The bottom is made of foam plastic, 5-7 cm thick, for one person; if you want to make a vessel for two or more passengers, then attach another similar sheet to the bottom. Next, you need to make two holes in the bottom: one for air flow, and the second to ensure the pillow is inflated. You can use a jigsaw.
Next, you need to insulate the lower part of the body from water - fiberglass is ideal for this. Apply it to the foam and treat it with epoxy. But unevenness and air bubbles may form on the surface; to prevent this, cover the fiberglass with plastic film and cover with a blanket. Place another layer of film on top and tape it to the floor. To blow the air out from under the resulting “sandwich”, use a regular vacuum cleaner. The bottom of the case will be ready in 2.5-3 hours.
The upper part of the body can be made arbitrary, but one should not forget about aerodynamics. Making a pillow is easy. You just need to properly secure it and synchronize it with the bottom - that is, make sure that the air flow from the engine passes through the hole into the cushion without losing efficiency.
Make the pipe for the motor from styrofoam, be careful with 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 installing the motor holder. Essentially, it’s just a stool on three legs that are attached to the bottom, and an engine is placed on top of it.
Engine
There are two options - a ready-made engine from the company Yu.H. or homemade. You can take it from a chainsaw or washing machine— the power they provide is quite enough for an amateur hovercraft. If you want something more, you should take a closer look at a scooter motor.
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 amphibians - hovercraft(AVP), study of their fundamental structure, comparison of various designs and circuits.
For this purpose, I visited many Internet sites of enthusiasts and creators of WUAs (including foreign ones), and met some of them in person.
In the end, the prototype of the planned boat was taken by the English Hovercraft (“floating ship” - that’s how the AVP is called in the UK), built and tested by local enthusiasts. Our most interesting domestic vehicles of this type were mostly created for law enforcement agencies, and in recent years- for commercial purposes, had large dimensions, and therefore were not suitable for amateur production.
My hovercraft (I call it “Aerojeep”) is a three-seater: the pilot and passengers are arranged in a T-shape, like on a tricycle: the pilot is in front in the middle, and the passengers are behind next to each other, one next to the other. The machine is single-engine, with a divided air flow, for which a special panel is installed in its annular channel slightly below its center.
| Technical data of the hovercraft | |
|---|---|
| Overall dimensions, mm: | |
| length | 3950 |
| width | 2400 |
| height | 1380 |
| Engine power, l. With. | 31 |
| Weight, kg | 150 |
| Load capacity, kg | 220 |
| Fuel capacity, l | 12 |
| Fuel consumption, l/h | 6 |
| Obstacles to be overcome: | |
| rise, deg. | 20 |
| wave, m | 0,5 |
| Cruising speed, km/h: | |
| by water | 50 |
| on the ground | 54 |
| on ice | 60 |
It consists of three main parts: a propeller-engine unit with a transmission, a fiberglass body and a “skirt” - a flexible fence for the lower part of the body - the “pillowcase” of the air cushion, so to speak.
 1 - segment (thick fabric); 2 - mooring cleat (3 pcs.); 3 - wind visor; 4 - side strip for fastening segments; 5 - handle (2 pcs.); 6 - propeller guard; 7 - ring channel; 8 - rudder (2 pcs.); 9 - steering wheel control lever; 10 - access hatch to the gas tank and battery; 11 - pilot's seat; 12 - passenger sofa; 13 - engine casing; 14 - engine; 15 - outer shell; 16 - filler (foam); 17 - inner shell; 18 - dividing panel; 19 - propeller; 20 - propeller hub; 21 - timing belt; 22 - node for fastening the lower part of the segment. enlarge, 2238x1557, 464 KB |
hovercraft hull
It is double: fiberglass, consists of an inner and outer shell.
The outer shell has a fairly simple configuration - it is just inclined (about 50° to the horizontal) sides without a bottom - flat across almost the entire width and slightly curved in the upper part. The bow is rounded, and the rear has the appearance of an inclined transom. In the upper part, along the perimeter of the outer shell, oblong holes-grooves are cut out, and at the bottom, from the outside, a cable enclosing the shell is fixed in eye bolts for attaching the lower parts of the segments to it.
The inner shell is more complex in configuration than the outer shell, since it has almost all the elements of a small vessel (say, a dinghy or a boat): sides, bottom, curved gunwales, a small deck in the bow (only the upper part of the transom in the stern is missing) - while being completed as one detail. In addition, in the middle of the cockpit along it, a separately molded tunnel with a canister under the driver’s seat is glued to the bottom. It houses the fuel tank and battery, as well as the throttle cable and the steering control cable.
In the aft part of the inner shell there is a kind of poop, raised and open at the front. It serves as the base of the annular channel for the propeller, and its jumper deck serves as an air flow separator, part of which (the supporting flow) is directed into the shaft opening, and the other part is used to create propulsive traction force.
All elements of the body: the inner and outer shells, the tunnel and the annular channel were glued onto matrices made of glass mat about 2 mm thick on polyester resin. Of course, these resins are inferior to vinyl ester and epoxy resins in terms of adhesion, level of filtration, shrinkage, and the release of harmful substances upon drying, but they 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 according to the 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 housing shells - about 4 mm). Before gluing the elements, all roughness and burrs were carefully removed from the working surface of the matrix, and it was covered three times with wax diluted in turpentine and polished. After this, a thin layer (up to 0.5 mm) of gelcoat (colored varnish) of the selected yellow color was applied to the surface with a sprayer (or roller).
After it 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 slot in the mat). In the same way, subsequent layers of glass mats are laid to the required thickness (4-5 mm), with the installation of embedded parts (metal and wood) where necessary. Excess flaps along the edges are cut off when gluing “wet-to-edge”.
After the resin has hardened, the shell is easily removed from the matrix and processed: the edges are turned, grooves are cut, and holes are drilled.
To ensure the unsinkability of the Aerojeep, pieces of foam plastic (for example, furniture) are glued to the inner shell, leaving only the channels for air passage around the entire perimeter free. Pieces of foam plastic are glued together with resin, and attached to the inner shell with strips of glass mat, also lubricated with resin.
After making the outer and inner shells separately, they are joined, fastened with clamps and self-tapping screws, and then connected (glued) along the perimeter with strips coated with polyester resin of the same glass mat, 40-50 mm wide, from which the shells themselves were made. After this, the body is left until the resin is completely polymerized.
A day later, a duralumin strip with a cross-section of 30x2 mm is attached to the upper joint of the shells along the perimeter with blind rivets, installing it vertically (the tongues of the segments are fixed on it). Wooden runners measuring 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, a base of wooden slab is installed under the engine.
It is worth noting that the same technology used to make the outer and inner shells was used to glue smaller elements: the inner and outer shells of the diffuser, steering wheels, gas tank, engine casing, wind deflector, tunnel and driver's seat. For those who are just starting to work with fiberglass, I recommend preparing the manufacture of a boat from these small elements. The total mass of the fiberglass body together with the diffuser and rudders is about 80 kg.
Of course, the production of such a hull can also be entrusted to specialists - companies that produce fiberglass boats and boats. Fortunately, there are a lot of them in Russia, and the costs will be comparable. However, in the process self-made You will be able to gain the necessary experience and the opportunity in the future to model and create various elements and structures from fiberglass yourself.
Propeller-powered hovercraft
It includes an engine, a propeller and a transmission that transmits torque from the first to the second.
The engine used is BRIGGS & STATTION, produced in Japan under an American license: 2-cylinder, V-shaped, four-stroke, 31 hp. With. at 3600 rpm. Its guaranteed service life is 600 thousand hours. Starting is carried out by an electric starter, from the battery, and the spark plugs work from the magneto.
The engine is mounted on the bottom of the Aerojeep's body, and the propeller hub axis is fixed at both ends to brackets in the center of the diffuser, raised above the body. The transmission of torque from the engine 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 large (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 machine, especially an “aeronautical” one.
The exhaust gases are discharged into the lower air flow.
Instead of the installed Japanese one, you can use suitable domestic engines, for example, from snowmobiles “Buran”, “Lynx” and others. By the way, for a one- or two-seat AVP, smaller engines with a power of about 22 hp are quite suitable. With.
The propeller is six-bladed, with a fixed pitch (angle of attack set on land) of the blades.
 1 - walls; 2 - cover with tongue. |
The annular channel of the propeller should also be considered an integral part of the propeller engine installation, although its base (lower sector) is integral with the inner shell of the housing. The annular channel, like the body, is also composite, glued together from outer and inner shells. Just in the place where its lower sector joins the upper one, a fiberglass dividing panel is installed: it separates 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 passengers' seats), is covered on top by a fiberglass hood, and the propeller, in addition to the diffuser, is also covered by a wire grille in front.
The soft elastic fencing of a hovercraft (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-made Vinyplan material, but domestic percale-type fabric is quite suitable. The segment pattern is simple, and you can even sew it by hand.
Each segment is attached to the body as follows. The tongue is placed over the side vertical bar, with an overlap of 1.5 cm; onto it is the tongue of the adjacent segment, and both of them, at the point of overlap, are secured to the bar with a special alligator clip, only without teeth. And so on around the entire perimeter of the Aerojeep. For reliability, you can also put a clip in the middle of the tongue. The two lower corners of the segment are suspended freely using nylon clamps on a cable that wraps around the lower part of the outer shell of the housing.
This composite design of the skirt allows you to easily replace a failed segment, which will take 5-10 minutes. It would be appropriate to say that the design is operational when up to 7% of the segments fail. In total, up to 60 pieces are placed on the skirt.
Principle of movement hovercraft next. After starting the engine and idling, the device remains in place. As the speed increases, the propeller begins to drive a more powerful air flow. Part of it (large) creates propulsive force and provides the boat with forward movement. The other part of the flow goes under the dividing panel into the side air ducts of the hull (the free space between the shells up to the very bow), and then through the slot-holes in the outer shell it evenly enters the segments. This flow, simultaneously with the start of movement, creates an air cushion under the bottom, lifting the apparatus above the underlying surface (be it soil, snow or water) by several centimeters.
The rotation of the Aerojeep is carried out by two rudders, which deflect the “forward” air flow to the side. The steering wheels are controlled from a double-arm motorcycle-type steering column lever, through a Bowden cable running along the starboard side between the shells to one of the steering wheels. The other steering wheel is connected to the first by a rigid rod.
A carburetor throttle control lever (analogous to a throttle grip) is also attached to the left handle of the double-arm lever.
To operate a hovercraft, you must register it with the local state inspection for small craft (GIMS) and obtain a ship's ticket. To obtain a certificate for the right to operate a boat, you must also complete a training course on how to operate a boat.
However, even these courses still do not have instructors for piloting hovercraft. Therefore, each pilot has to master the management of the AVP independently, literally gaining the relevant experience bit by bit.
Poor network condition highways and the almost complete absence of road infrastructure on most regional routes forces us to look for vehicles operating on different physical principles. One such means is a hovercraft capable of moving people and cargo in off-road conditions.
Hovercraft carrying sonorous technical term“Hovercraft” differs from traditional models of boats and cars not only in its ability to move on any surface (pond, field, swamp, etc.), but also in the ability to develop decent speed. The only requirement for such a “road” is that it must be more or less smooth and relatively soft.
However, the use of an air cushion by an all-terrain boat requires quite serious energy costs, which in turn entails a significant increase in fuel consumption. The operation of hovercraft (hovercraft) is based on a combination of the following physical principles:
- Low specific pressure of the hovercraft on the surface of the soil or water.
- High speed movement.
This factor has a fairly simple and logical explanation. The area of contact surfaces (the bottom of the apparatus and, for example, the soil) corresponds to or exceeds the area of the hovercraft. Speaking technical language, the vehicle dynamically creates a support thrust of the required magnitude.
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 for fast and, most importantly, economical movement, the scope of application of a hovercraft on the surface of the earth is significantly limited. Asphalt areas, hard rocks with the presence of industrial waste or hard stones are absolutely unsuitable for it, since the risk of damage to the main element of the hovercraft - the bottom of the cushion - increases significantly.
Thus, the optimal hovercraft route can be considered one where you need to swim a lot and drive 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 do you want to make a hovercraft with your own hands? There are several reasons:
That is why SVPs have not become widespread. Indeed, you can buy an ATV or a snowmobile as an expensive toy. Another option is to make a boat-car yourself.
When choosing a working scheme, it is necessary to decide on a housing design that optimally meets the given technical conditions. Note that it is quite possible to create a hovercraft with your own hands with drawings for assembling homemade elements.
Specialized resources abound with ready-made drawings of homemade hovercraft. Analysis of practical tests shows that the most successful option, satisfying the conditions that arise when moving on water and soil, are pillows formed by the chamber method.
When choosing a material for the main structural element of an hovercraft - the body, consider several important criteria. Firstly, it is simplicity and ease of processing. Secondly, small specific gravity material. It is this parameter that ensures that the hovercraft belongs to the “amphibious” category, that is, there is no risk of flooding in the event emergency stop vessel.
As a rule, 4 mm plywood is used to make the body, and the superstructures are made of foam plastic. This significantly reduces the dead weight of the structure. After gluing the external surfaces with penoplex and subsequent painting, the model acquires its original features appearance original. Polymer materials are used to glaze the cabin, and the remaining elements are bent from wire.
Making a so-called skirt will require a dense, waterproof fabric made of polymer fiber. After cutting, the parts are sewn together with a double tight seam, and gluing is done using waterproof glue. This ensures not only a high degree of structural reliability, but also allows you to hide the installation joints from prying eyes.
The design of the power plant assumes the presence of two engines: marching and forcing. They are equipped with brushless electric motors and two-bladed propellers. A special regulator carries out the process of managing them.
The supply voltage is supplied from two batteries, the total capacity of which is 3,000 milliamps per hour. At the maximum charge level, the hovercraft can be operated for 25-30 minutes.
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One winter, when I was walking 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, which could be used in winter.
After much thought, my choice fell on a double hovercraft. At first I had nothing but a great desire to create such a design. The technical literature available to me summarized the experience of creating only large hovercraft, but I could not find any data on small devices for recreational and sports purposes, especially since our industry does not produce such hovercraft. So, one could only rely on one’s own strength and experience (my amphibious boat based on the Yantar motorboat was once reported in KYa; see No. 61).
Anticipating that in the future I may have followers, and if positive results Industry may also be interested in my device, I decided to design it on the basis of well-developed and commercially available two-stroke engines.
In principle, a hovercraft experiences significantly less stress than a traditional planing boat hull; this allows its design to be made lighter. At the same time, there appears additional requirement: the body of the device must have low aerodynamic resistance. This must be taken into account when developing a theoretical drawing.
| Basic data of an amphibious hovercraft | |
|---|---|
| Length, m | 3,70 |
| Width, m | 1,80 |
| Side height, m | 0,60 |
| Air cushion height, m | 0,30 |
| Lifting unit power, l. With. | 12 |
| Traction unit power, l. With. | 25 |
| Payload capacity, 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 - fan shaft bearings; 14 - windshield; 15 - flexible fencing; 16 - traction fan; 17 - traction fan casing; 18 - lifting motor; 19 - lifting engine muffler; 20 - electric starter; 21 - battery; 22 - fuel tank.
I made the body kit from spruce slats with a section of 50x30 and covered it with 4 mm plywood with epoxy glue. I did not cover it with fiberglass, for fear of increasing the weight of the device. To ensure unsinkability, two waterproof bulkheads were installed in each of the side compartments, and the compartments were also filled with foam plastic.
A two-engine power plant scheme was chosen, i.e. one of the engines works to lift the apparatus, creating excess pressure (air cushion) under its bottom, and the second provides movement - creates horizontal thrust. Based on the calculations, the lifting engine should have a power of 10-15 hp. With. Based on the basic data, the engine from the Tula-200 scooter turned out to be the most suitable, 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 unit, together with fastenings and electric starter, was about 30 kg.
One of the most difficult stages was the manufacture of the skirt - a flexible cushion enclosure that quickly wears out during use. A commercially available tarpaulin fabric with a width of 0.75 m was used. Due to the complex configuration of the joints, about 14 m of such fabric was required. The strip was cut into pieces equal to the length of the side, with allowance for a rather complex shape of the joints. After giving the required shape, the joints were stitched. The edges of the fabric were attached to the body of the apparatus with 2x20 duralumin strips. To increase wear resistance, I impregnated the installed flexible fencing with rubber glue, to which I added aluminum powder, which gives it an elegant look. This technology makes it possible to restore a flexible fence in the event of an accident and as it wears out, similar to extending the tread of a car tire. It must be emphasized that the manufacture of flexible fencing not only takes a lot of time, but requires special care and patience.
The hull was assembled and the flexible fencing was installed with the keel up. Then the hull was rolled out and a lifting power unit was installed in a shaft measuring 800x800. The installation control system was installed, and now the most crucial moment came; testing it. Will the calculations be justified, will a relatively low-power engine lift such a device?
Already at medium engine speeds, the amphibian rose with me and hovered at a height of about 30 cm from the ground. The reserve of lifting force turned out to be quite enough for the warmed-up engine to lift even four people at full speed. In the very first minutes of these tests, the features of the device began to emerge. After proper alignment, it moved freely on an air cushion in any direction, even with a small applied force. It seemed as if he was floating on the surface of the water.
The success of the first test of the lifting installation and the hull as a whole gave me inspiration. Having secured the windshield, I began installing the traction power unit. At first it seemed advisable to take advantage of the extensive experience in building and operating snowmobiles and install an engine with a propeller relatively large diameter on the aft deck. However, it should be taken into account that such a “classic” version would significantly increase the center of gravity of such a small device, which would inevitably affect its driving performance and, most importantly, safety. Therefore, I decided to use two traction engines, completely similar to the lifting one, and installed them in the stern of the amphibian, but not on the deck, but along the sides. After I had fabricated and installed a motorcycle-type control drive and installed relatively small-diameter traction propellers (“fans”), the first version of the hovercraft was ready for sea trials.
To transport the amphibian behind a Zhiguli car, a special trailer was made, and in the summer of 1978 I loaded my device onto it and delivered it to a meadow near a lake near Riga. The exciting moment has arrived. Surrounded by friends and curious people, I took the driver's seat, started the lift engine, and my new boat hung over the meadow. Started both traction engines. As the number of their revolutions increased, the amphibian began to move across the meadow. And then it became clear that many years of experience in driving a car and a motorboat were clearly not enough. All previous skills are no longer suitable. It is necessary to master methods of controlling a hovercraft, which can spin indefinitely in one place, like a spinning top. As the speed increased, the turning radius also increased. Any surface irregularities caused the apparatus to rotate.
Having mastered the controls, I directed the amphibian along the gently sloping shore towards the surface of the lake. Once above the water, the device immediately began to lose speed. The traction engines began to stall one by one, flooded with spray escaping from under the flexible air cushion enclosure. When passing through overgrown areas of the lake, the fans sucked in reeds, and the edges of their blades became discolored. When I turned off the engines and then decided to try to take off from the water, nothing happened: my device was never able to escape from the “hole” formed by the pillow.
All in all, it was a failure. However, the first defeat did not stop me. I came to the conclusion that, given the existing characteristics, the power of the traction system is insufficient for my hovercraft; 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 body to 3.70 m and its width to 1.80 m. I also designed a completely new traction unit, completely protected from splashes and from contact with grass and reeds. To simplify the control of the installation and reduce its weight, one traction motor is used instead of two. The power head of a 25-horsepower Vikhr-M outboard motor with a completely redesigned cooling system was used. The 1.5 liter closed cooling system is filled with antifreeze. The engine torque is transmitted to the fan “propeller” shaft located across the device using two V-belts. Six-bladed fans force air into the chamber, from which it escapes (at the same time cooling the engine) behind the stern through a square nozzle equipped with control flaps. From an aerodynamic point of view, such a traction 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 mid-summer 1979, my apparatus was again transported to the same meadow. Having mastered the controls, I directed it towards the lake. This time, once above the water, he continued moving 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 a Vikhr-M engine set off on a parallel course, but soon fell behind.
The described apparatus caused particular surprise among ice fishing enthusiasts when I continued testing the amphibian in winter on ice, which was covered with a layer of snow about 30 cm thick. It was a real expanse on the ice! The speed could be increased to maximum. I didn’t measure it exactly, but the driver’s experience allows me to say that it was approaching 100 km/h. At the same time, the amphibian freely overcame the deep tracks left by the motor guns.
A short film was shot and shown at the Riga television studio, after which I began to receive many requests from those who wanted to build such an amphibious vehicle.