Homemade hovercraft. We make our own hovercraft

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 device on air cushion . 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 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 hope for 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 might have followers, and if the results are positive, industry might 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 set from spruce slats with a section of 50x30 and covered it with 4 mm plywood on 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 has been chosen, 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. 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 an allowance of quite complex shape 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 building up a tread 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 relatively large diameter propeller 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 device would significantly increase, 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 lifting 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 Driving a car or a motorboat is 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 when existing characteristics for my hovercraft the power of the traction system 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 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. A 25-horsepower power head was used. outboard motor"Vikhr-M" with a completely redesigned cooling system. Closed system cooling container with a volume of 1.5 liters 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.

A hovercraft is a vehicle that can travel both on water and on land. It’s not at all difficult to make such a vehicle with your own hands.

This is a device that combines the functions of a car and a boat. The result was a hovercraft (hovercraft), which has unique cross-country characteristics, without loss of speed when moving through water due to the fact that the hull of the vessel does not move through the water, but above its surface. This made it possible to move through the water much faster, due to the fact that the friction force of the water masses does not provide any resistance.

Although the hovercraft has a number of advantages, its field of application is not so widespread. The fact is that this device cannot move on any surface without any problems. It requires soft sandy or soil soil, without stones or other obstacles. The presence of asphalt and other hard bases can render the bottom of the vessel, which creates an air cushion when moving, unusable. In this regard, “hovercrafts” are used where you need to sail more and drive less. If on the contrary, then it is better to use the services of an amphibious vehicle with wheels. The ideal conditions for their use are difficult-to-pass swampy places where no other vehicle except a hovercraft (hovercraft) can pass. Therefore, hovercrafts have not become so widespread, although similar transport is used by rescuers in some countries, such as Canada, for example. According to some reports, SVPs are in service with NATO countries.

How to purchase such a vehicle or how to make it yourself?

Hovercraft is an expensive mode of transport, average price which reaches 700 thousand rubles. Scooter-type transport costs 10 times less. But at the same time, one should take into account the fact that factory-made transport is always different best quality, compared to homemade products. Yes and reliability vehicle higher. In addition, factory models are accompanied by factory warranties, which cannot be said about structures assembled in garages.

Factory models have always been focused on a narrowly professional area related to either fishing, hunting, or special services. As for homemade hovercraft, they are extremely rare and there are reasons for this.

These reasons include:

• Enough high cost, as well as expensive maintenance. The main elements of the device wear out quickly, which requires their replacement. Moreover, each such repair will cost a pretty penny. Only a rich person will afford to buy such a device, and even then he will think again whether it is worth getting involved with it. The fact is that such workshops are as rare as the vehicle itself. Therefore, it is more profitable to purchase a jet ski or ATV for moving on water.
• The operating product creates a lot of noise, so you can only move around with headphones.
• When moving against the wind, the speed drops significantly and fuel consumption increases significantly. Therefore, homemade hovercraft is more of a demonstration of one’s professional abilities. You not only need to be able to operate a vessel, but also be able to repair it, without significant expenditure of funds.

DIY SVP manufacturing process

Firstly, assembling a good hovercraft at home is not so easy. To do this you need to have the opportunity, desire and professional skills. A technical education wouldn't hurt either. If the last condition is absent, then it is better to refuse to build the apparatus, otherwise you may crash on it during the first test.

All work begins with sketches, which are then transformed into working drawings. When creating sketches, you should remember that this device should be as streamlined as possible so as not to create unnecessary resistance when moving. At this stage, one should take into account the fact that this is practically an aerial vehicle, although it is very low to the surface of the earth. If all conditions are taken into account, then you can begin to develop drawings.

The figure shows a sketch of the SVP of the Canadian Rescue Service.

Technical data of the device

As a rule, all hovercraft are capable of achieving decent speeds that no boat can achieve. This is when you consider that the boat and hovercraft have the same mass and engine power.

At the same time, the proposed model of a single-seat hovercraft is designed for a pilot weighing from 100 to 120 kilograms.

As for driving a vehicle, it is quite specific and does not fit in with driving a regular motor boat. Specificity is associated not only with the presence high speed, but also a method of transportation.

The main nuance is related to the fact that when turning, especially at high speeds, the ship skids strongly. To minimize this factor, you need to lean to the side when turning. But these are short-term difficulties. Over time, the control technique is mastered and the hovercraft can demonstrate miracles of maneuverability.

What materials are needed?

Basically you will need plywood, foam plastic and a special construction kit from Universal Hovercraft, which includes everything you need for self-assembly vehicle. The kit includes insulation, screws, air cushion fabric, special glue and more. This set can be ordered on the official website by paying 500 bucks for it. The kit also includes several variants of drawings for assembling the SVP apparatus.

Since the drawings are already available, the shape of the vessel should be linked to the finished drawing. But if you have a technical background, then, most likely, a ship will be built that is not similar to any of the options.

The bottom of the vessel is made of foam plastic, 5-7 cm thick. If you need a device to transport more than one passenger, then another sheet of foam plastic is attached to the bottom. After this, two holes are made in the bottom: one is intended for air flow, and the second is to provide the pillow with air. Holes are cut using an electric jigsaw.

At the next stage, the lower part of the vehicle is sealed from moisture. To do this, take fiberglass and glue it to the foam using epoxy glue. At the same time, unevenness and air bubbles may form on the surface. To get rid of them, the surface is covered with polyethylene and a blanket on top. Then, another layer of film is placed on the blanket, after which it is fixed to the base with tape. It is better to blow the air out of this “sandwich” using a vacuum cleaner. After 2 or 3 hours epoxy resin It will harden and the bottom will be ready for further work.

The top of the body can have any shape, but take into account the laws of aerodynamics. After this, they begin to attach the pillow. The most important thing is that air enters it without loss.

The pipe for the motor should be made of styrofoam. The main thing here is to guess the size: if the pipe is too large, then you will not get the traction that is necessary to lift the hovercraft. Then you should pay attention to mounting the motor. The motor holder is a kind of stool consisting of 3 legs attached to the bottom. The engine is installed on top of this “stool”.

What engine do you need?

There are two options: the first option is to use an engine from Universal Hovercraft or use any suitable engine. This could be a chainsaw engine, the power of which is quite enough for a homemade device. If you want to get a more powerful device, then you should take a more powerful engine.

It is advisable to use factory-made blades (those included in the kit), since they require careful balancing and this is quite difficult to do at home. If this is not done, the unbalanced blades will destroy the entire engine.

How reliable can a hovercraft be?

As practice shows, factory hovercraft (hovercraft) have to be repaired about once every six months. But these problems are insignificant and do not require serious costs. Basically, the airbag and air supply system fail. In fact, the likelihood is that homemade device will fall apart during operation, it is very small if the “hovercraft” is assembled competently and correctly. For this to happen, you need to run into some obstacle at high speed. Despite this, the air cushion is still able to protect the device from serious damage.

Rescuers working on similar devices in Canada repair them quickly and competently. As for the pillow, it can actually be repaired in a regular garage.

Such a model will be reliable if:

• The materials and parts used were of good quality.
• The device has a new engine installed.
• All connections and fastenings are made reliably.
• The manufacturer has all the necessary skills.

If the SVP is made as a toy for a child, then in this case it is desirable that the data of a good designer be present. Although this is not an indicator for putting children behind the wheel of this vehicle. This is not a car or a boat. Operating a hovercraft is not as easy as it seems.

Taking this factor into account, you need to immediately begin manufacturing a two-seater version in order to control the actions of the one who will sit behind the wheel.

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 force of sliding friction and the resistance force of water masses 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 mainly products self made, 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

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:

1. 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.
2. More sensitive gear. Read the appropriate manuals for the specific type of gear on the pages of my website.
3. Lures based pheromones.

Other secrets successful fishing you can get it for free by reading my other materials on the site.

Making a good SVP is not easy, but if you think about it, then most likely you either have the ability or the desire, but keep in mind that if you don’t have technical education, 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.

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 is absolutely different speeds, and secondly, 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 bottom part housings from water - fiberglass is ideal for this. Apply it to the foam and treat it with epoxy. But uneven surfaces and air bubbles may form on the surface, to prevent this, cover the fiberglass 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 air flow from the engine passed through the hole into the pillow without losing efficiency.

Make the pipe for the motor from styrofoam, do not go wrong with the dimensions so that the screw fits into it, but the gap between its edges and internal part the pipe was not very large, as this would reduce draft. 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.

It all started with the fact that I wanted to do some project and involve my grandson in it. I have a lot of engineering experience behind me, so simple projects I wasn’t looking, and then one day, while watching TV, I saw a boat that was moving due to the propeller. "Cool stuff!" - I thought, and began to scour the Internet in search of at least some information.

We took the motor from an old lawn mower, and bought the layout itself (costs $30). It is good because it requires only one motor, while most similar boats require two engines. From the same company we bought the propeller, propeller hub, air cushion fabric, epoxy resin, fiberglass and screws (they sell them all in one kit). The remaining materials are quite commonplace and can be purchased at any hardware store. The final budget was a little over $600.

Step 1: Materials

Materials you will need: polystyrene foam, plywood, kit from Universal Hovercraft (~$500). The kit contains all the little things you need to complete the project: plan, fiberglass, propeller, propeller hub, air cushion fabric, glue, epoxy resin, bushings, etc. As I wrote in the description, all materials cost about $600.

Step 2: Making the frame

We take polystyrene foam (5 cm thick) and cut out a 1.5 by 2 meter rectangle from it. Such dimensions will ensure buoyancy of a weight of ~270 kg. If 270 kg seems not enough, you can take another sheet of the same type and attach it below. We cut out two holes with a jigsaw: one for the incoming air flow and the other for inflating the pillow.

Step 3: Cover with fiberglass

The lower part of the body must be waterproof, for this we cover it with fiberglass and epoxy. In order for everything to dry properly, without unevenness and roughness, you need to get rid of any air bubbles that may arise. You can use an industrial vacuum cleaner for this. We cover the fiberglass with a layer of film, then cover it with a blanket. The covering is necessary to prevent the blanket from sticking to the fiber. Then we cover the blanket with another layer of film and glue it to the floor with adhesive tape. We make a small cut, insert the trunk of the vacuum cleaner into it and turn it on. We leave it in this position for a couple of hours, when the procedure is completed, the plastic can be scraped off from the fiberglass without any effort, it will not stick to it.

Step 4: Bottom Case is Ready

The lower part of the body is ready, and now it looks something like the photo.

Step 5: Making the Pipe

The pipe is made of styrofoam, 2.5 cm thick. It is difficult to describe the whole process, but in the plan it is described in detail, we did not have any problems at this stage. Let me just note that the plywood disk is temporary and will be removed in subsequent steps.

Step 6: Motor Holder

The design is not tricky; it is made of plywood and blocks. Placed exactly in the center of the boat hull. Attaches with glue and screws.

Step 7: Propeller

The propeller can be purchased in two forms: ready-made and “semi-finished”. Ready-made ones are usually much more expensive, and buying a semi-finished product can save a lot of money. That's what we did.

The closer the propeller blades are to the edges of the air vent, the more efficiently the latter works. Once you have decided on the gap, you can sand the blades. Once the grinding is completed, it is necessary to balance the blades so that there are no vibrations in the future. If one of the blades weighs more than the other, then the weight needs to be equalized, but not by cutting the ends, or by grinding. Once the balance is found, you can apply a couple of layers of paint to maintain it. For safety, it is advisable to paint the tips of the blades white.

Step 8: Air Chamber

The air chamber separates the flow of incoming and outgoing air. Made from 3 mm plywood.

Step 9: Installing the Air Chamber

The air chamber is attached with glue, but you can also use fiberglass; I always prefer to use fiber.

Step 10: Guides

The guides are made of 1 mm plywood. To give them strength, cover them with one layer of fiberglass. It’s not very clear in the photo, but you can still see that both guides are connected together at the bottom with an aluminum strip, this is done so that they work synchronously.

Step 11: Shape the Boat and Add Side Panels

The outline of the shape/contour is made on the bottom, after which a wooden plank is attached with screws according to the outline. 3mm plywood bends well and fits right into the shape we need. Next we fasten and glue the 2 cm beam along top edge plywood sides. Add cross beam, and install the handle, which will be the steering wheel. We attach cables to it extending from the guide blades installed earlier. Now you can paint the boat, preferably applying several layers. We chose white; even with prolonged direct sunlight, the body practically does not heat up.

I must say that she swims briskly, and this makes me happy, but it surprised me steering. At medium speeds turns are possible, but at high speed the boat first skids to the side, and then by inertia it moves backwards for some time. Although, after getting used to it a little, I realized that tilting my body in the direction of the turn and slightly slowing down the gas can significantly reduce this effect. Exact speed It’s hard to say, because there is no speedometer on the boat, but it feels quite good, and there is still a decent wake and waves left behind the boat.

On the day of the test, about 10 people tried the boat, the heaviest weighed about 140 kg, and it withstood it, although of course it was not possible to achieve the speed that was available to us. With a weight of up to 100 kg, the boat moves briskly.

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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 various designs and schemes.

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 machines of this type mostly were 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. Bow- rounded, and the rear one 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 adhesion, filtration level, shrinkage, and release harmful substances when dry, but have 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 elements with work surface the matrix was carefully removed all roughness and burrs, and it was covered three times with wax diluted in turpentine and polished. After this, it was applied to the surface with a spray (or roller) thin layer(up to 0.5 mm) gelcoat (colored varnish) of the selected yellow color.

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 of coated polyester resin 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 inside the shell, in the aft part of the cockpit, a base is made of wooden slab 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. Gross weight fiberglass body together with diffuser and rudders - 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 of self-production, it will be possible 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 inner shell housings. 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 light 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. Two bottom corners The segments are suspended freely using nylon clamps on a cable that wraps around the lower part of the outer shell of the housing.

Such composite design 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.