Homemade propeller for a homemade aircraft. Calculation and manufacture of a propeller

Find a design pattern. Try to find a suitable design template for the propeller. It is important to know the engine power, propeller diameter and RPM in order to select wooden propeller drawings and templates for such specifications. Find a template online or borrow a special book from the library. Some of the books have pattern drawings, which will do just fine.

Determine the number of blades. Most often, the propeller has two, three or four blades. Larger aircraft may use propellers with even more blades. The more powerful the drive motor, the more blades are needed to evenly distribute power. Although you can make a three- or four-blade propeller if you really want to, it's still better to start with a simple two-blade propeller if this is your first experience. The more blades, the higher the cost, weight of the finished product and time costs.

Determine the length of the blades. As with quantity, increasing the blade length allows for a more powerful motor. Also note that the maximum blade length is always limited by the distance to the ground. Measure the distance from the nose of the aircraft to the surface to get an idea of the limitations.

Aerodynamic profile. The propeller blade thickens near the motor shaft hub at a high angle of inclination, while the tip of the blade is always thin with a small angle of inclination. Determine the blade width and angle of attack. The propeller blades are attached to the hub at an angle similar to the threads on screws and wood screws.

Proper bending of the propeller blades. Blade propeller resembles a curved wing. Due to the bend, the propeller pushes air or water more efficiently. The tips of the blades always move much faster than the hub on the shaft. The blades must be bent so that the propeller maintains the same angle of attack along the entire length of the blade. Use a special calculator to calculate the required slope.

Choose blade material. The stronger a wooden propeller is made, the better it will cope with aircraft vibrations. Use a strong but lightweight wood like maple or birch. When choosing wood, pay attention to the texture of the fibers. Straight and evenly distributed fibers will balance the propeller.

Use 6-8 boards 2 to 2.5 centimeters thick and about 2 meters long. Spare boards also come in handy. The more layers, the stronger the propeller will be, even if each layer is very thin. To save time, you can contact material suppliers who produce plywood.

A couple of weeks ago, I installed one of my wind turbines to help solar panels. I put the blades on it which I found, two blades from the 160th pipe and two from galvanized sheet. The screw seemed to work, but I wanted to make a normal screw, so that it would be fast and with a good starting moment. Below in the picture is a windmill with prefabricated blades, the quality is of course disgusting, but I think it’s clear what is shown.

Pipes 110.160 mm with a speed of 5-6 did not want to show a good starting moment in the program, and it is problematic to find pipes with a larger diameter. Good result in the program for calculating the blades from PVC pipes gave pipes 250.315 mm, and the starting moment is high, and speed with KIEV.

Then I decided to try to make blades from tin, more precisely from scraps of professional flooring, which remained after sheathing the house with professional flooring. Previously, in the program, I adjusted the screw from the 315th pipe for my generator. The three-bladed propeller turned out to be 1.5m in diameter, speed with high KIEV 5-7, the starting torque at 5m / s is 0.25Nm. Below are screenshots from the program for calculating the blades.

Here, the data for cutting the propeller are all dimensions in millimeters, according to which I made the blades further.

From scraps of professional flooring, I chose three suitable small pieces and cut them with a 75cm grinder. Then, with the help of a hammer, he began to straighten the profile into a kind of smooth sheet. I immediately folded the back edge with a grip of 1 cm.

Next, on the workpiece, I outlined the dimensions from the program and drew a front line along which I would cut the blade. I added 1 cm to the dimensions, as I will bend the front part for rigidity. Below in the photo you can see the line along which I will bend the tin with pliers. The thickness of the tin is 0.6mm, but I cut it out with ordinary scissors, and not with a grinder, it's smoother and easier.

The process of bending the edges of the blade. The hem is made with pliers and then tapped with a hammer

The manufacturing process of the rest of the blades is the same, it took about twenty minutes of work for one blade and as a result we got such still flat blades.

This is what the blades look like from the back.

Next, by longitudinal tapping with a hammer, I gave the blades the shape of grooves approximately like the 315th pipe. In order to roughly guess, I drew a circle with a diameter of 320 mm on the floor and guided myself along it. I subjected the root part of the blades to 3 cm, and folding the blades together drilled holes along the zero line. Drilled holes with a diameter of 6mm.

View from the back.

So after spending about an hour and a half, I made the blades for the wind generator. The blades turned out to be flimsy, of course, but as practice has shown, such blades can withstand winds up to 15 m / s. Next, I cut a hub out of plywood and already assembled the finished screw.

Below is a photo of this screw already on the wind generator.

After being installed on the wind turbine, the new propeller immediately showed its good side. On the street there was a wind of about 3-6 m / s and the screw was spinning well with a noticeably higher speed. Instantly responded to changes in wind speed and spun without stopping. Before him, at first, a prefabricated four-bladed propeller melted, but somehow he did not gain high speed. Then I removed two pieces of tin blades and two blades from the 150th pipe remained there. I connected the windings of the generator with a triangle and in this form the windmill worked with a two-blade propeller, but the propeller periodically stopped and then it was difficult to start. The charging current was unstable, but on gusts with today's wind it reached 4A.

With the new three-bladed propeller, charging is almost constant, 0.5-1A is constantly visible on the ammeter with an increase to 2A. Let's see how it will be for more strong wind but it's already good. Due to the speed, charging does not stop and the screw starts easily, which is what I wanted to do. And I think the strength of the screw is sufficient, but time will tell. I have not seen screws for wind turbines made of tin on the Internet and, of course, they cannot be compared in strength even with PVC pipes, but this is also a way out when it is problematic to get sewer pipes of large diameters.

Tin wind turbine screw
Photo report of the manufacture of a propeller for a wind turbine. A windmill from an auto-generator, a three-blade propeller 1.5m made of tin

The main part of the wind generator is a screw, which converts wind energy into mechanical work. So the better the screw, the more and more stable the wind generator will be able to generate electricity.

Materials used to create the screw:
1) corrugated board thickness 0.6mm
2) grinder
3) hammer
4) pliers
5) metal scissors

Let us consider in more detail the main points of work on the creation of a screw.

To begin with, he proceeded to the basic calculations. First, pipes with a diameter of 110 and 160 mm were tested, since they were available from the author, but with good high-speed qualities, it was not possible to achieve a sufficient starting moment from them. Then he decided to check which diameter would be the most acceptable from the side of the program. Calculations showed that PVC pipes with a diameter of 250 and 315 mm have the best coefficient. They have excellent indicators of both speed and starting torque.

But since there were no pipes of this diameter and it was quite difficult to find them, he decided to make the blades from tin, which remained from the sheathing of the house with corrugated board. Preliminary calculations were made with a screw from the 315th pipe in the program. The screw consisted of three blades and was obtained with a diameter of about 1.5 meters. According to calculations, the speed of such a propeller was obtained with a high KIEV 5-7, and the starting moment with a wind of 5 ms was equal to 0.25 Nm.

Below are excerpts from the program for calculating the efficiency of the blades:

Below are all the basic calculations and data on dimensions in millimeters, on the basis of which I began to manufacture the blades of the future propeller.

From the scraps of the flooring, the most suitable pieces were selected in the amount of three pieces and processed with a grinder up to 75 cm. With the help of a hammer, the profile was given the appearance of a smooth sheet, and the rear edge was immediately bent with a grip of 10 mm.

Further, on the received sheets, the author made a marking of the front line of work, along which the blades were subsequently cut out. One centimeter was added to the main dimensions, as the author decided to bend the edges in order to stiffen the structure. The photographs below show the line along which the metal will be bent. The thickness of the tin turned out to be about 0.6 mm, which made it possible to cope with metal scissors, and not a grinder, due to which the blades turned out to be more even.

For rigidity, the edges of the blades were bent. This was done with the help of pliers, followed by tapping with a hammer.

With the help of longitudinal tapping with a hammer, the blades were given the shape of troughs similar to the 315th pipe. For visual understanding, he drew a circle with a diameter of 320 mm and was guided by it when manipulating the shape of the blades. Holes with a diameter of 6 mm were also drilled for the subsequent assembly of the screw.

After installing this screw, it immediately showed itself with better side. With a wind speed of 3-5 ms, it gained momentum perfectly and instantly responded to changes in the wind. Prior to this, the screws installed on the generator either stopped periodically, or did not have enough turns to deliver a stable current.

Now the charging has become almost constant, the current strength is from 0.5-1 A and constantly increases to 2 A. Due to the high speed, charging does not stop, even with a slight wind. Thus, the author found an excellent way to build a reliable and stable propeller for a windmill from improvised means, which he sought. This guide may help you if you are also having trouble finding large PVC pipes in your area.
Source

Efficient propeller for wind generator
The main part of the wind generator is a screw, which converts wind energy into mechanical work. So the better the screw, the more and more stable the wind generator will be able to generate

Assembly instructions

There are several types of wind turbines: horizontal and vertical, turbine. They have fundamental differences, pluses and minuses. The principle of operation of all wind generators is the same - wind energy is converted into electrical energy and accumulated in batteries, and from them it goes to human needs. The most common type is horizontal.

Familiar and recognizable. The advantage of a horizontal wind generator is a higher efficiency compared to others, since the windmill blades are always under the influence of air flow. The disadvantages include the requirement for wind above 5 meters per second. This type of windmill is the easiest to make, so home craftsmen often take it as a basis.

If you decide to try your hand at assembling a wind turbine with your own hands, here are a few recommendations. You need to start with the generator, this is the heart of the system, the design of the screw assembly depends on its parameter. For this, automobile, imported ones are suitable, there is information about the use of stepper motors, from printers or other office equipment. You can also use a bicycle wheel motor to make your own windmill to generate electricity.

Having decided on the unit for converting the wind flow into electric current, it is necessary to assemble the gear unit for increasing the speed from the screw to the generator shaft. One revolution of the propeller transfers 4-5 revolutions to the shaft of the generator unit.

When the gearbox-generator assembly is assembled, they begin to find out its resistance to torque (grams per millimeter). To do this, you need to make a shoulder with a counterweight on the shaft of the future installation, and with the help of a load, find out at what weight the shoulder will go down. Less than 200 grams per meter is considered acceptable. Knowing the size of the shoulder, this is our blade length.

Many people think that the more blades the better. This is not entirely true, since we make the wind generator ourselves, and the details of the future power plant of the budget range. We need high speed, and a lot of screws create more resistance wind, as a result of which at some point the oncoming flow slows down the screw and the efficiency of the installation drops. This can be avoided by a two-bladed propeller. Such a propeller in a normal wind can spin up to and more than 1000 revolutions. You can make the blades of a homemade wind generator from improvised means - from plywood and galvanizing to plastic from water pipes (as in the photo below) and other things. The main thing condition easy and durable.

A light screw will increase the efficiency of the windmill and sensitivity to air flow. Don't forget to balance the air wheel and remove bumps, otherwise you will hear howling and howling while the generator is running.

The next important element is the tail. It will keep the wheel in the wind flow, and turn the structure in case of a change in its direction.

To make a current collector or not, it's up to you, you may get by with a connector on the cable and periodically, manually unwind the twisted wire. During the test run of the wind generator, do not forget about safety precautions, the blades spun in the wind can chop cabbage like a samurai.

A tuned, balanced windmill is installed on a mast, at least 7 meters high from the ground, fixed with spacer cables. Further, an equally important node, a storage battery, it can be an old car that has lost its capacity or battery. It is impossible to connect the output of a homemade wind generator directly to the battery, this must be done through a charging relay, you can assemble it yourself or purchase it ready-made.

The principle of operation of the relay is to control the charge, and in the event of a charge, it switches the generator and battery to load ballast, the system strives to always be charged, preventing overcharging, and does not leave the generator without load. A windmill without load can spin up quite strongly to high speeds, damage the insulation in the windings by the generated potential. In addition, high speeds can cause mechanical destruction of the elements of the wind generator. Next is a voltage converter from 12 to 220 volts 50 Hz for connecting household appliances.

Here we have provided all the most simple ideas for assembling a homemade windmill. As you can see, even a child can easily make some models of devices. There are many other homemade options, but in order to get high voltage at the output, you need to use complex mechanisms, such as magnet generators. Otherwise, if you want to make a wind generator so that it works and is used for its intended purpose, follow the instructions provided by us!

7 ideas for building a homemade windmill
Ideas on how to make a wind generator with your own hands at home. Photos, diagrams and drawings of homemade windmills. Video tutorials on assembling a wind generator.

Home wind farms are an independent alternative way to generate electricity.

The installation of such equipment can significantly reduce the cost of electricity, provided that there are winds of at least 4 m/s in the area.

And the higher the wind speed, the more energy is generated by the device.

This article will consider a step-by-step plan for making wind turbine blades with your own hands.

wind farms

There are many design options for wind turbines, for the classification of which there are basic features:

position of the rotational axis: vertical and horizontal,
number of blades: more often from 1 to 6, but there are options with a large number,
type of rotational blade: in the form of a wing or a sail,
blade material: wood, aluminum, PVC,
helical wheel design: fixed or variable pitch.

The productivity of a wind generator largely depends on the blades: on how correctly their dimensions and number are calculated, and whether the material for manufacturing is well chosen.

Making blades with your own hands is not difficult, but before you start work, you need to study some facts:

The longer the blades, the easier they are to move the wind, even the weakest. However, a longer length will slow down the speed of rotation of the wind wheel.
The sensitivity of the wind wheel is also affected by the number of blades: the more of them, the easier it will be to start the rotation. At the same time, power and speed indicators will decrease, which means that such a device is unsuitable for generating electricity, but it is perfect for lifting work.
The noise level emanating from the device depends on the diameter and speed of rotation of the wind wheel. This must be taken into account when installing a wind turbine near residential buildings.
More energy from the wind can be obtained by installing a windmill as high as possible above ground level (optimally from 6 to 15 m). Therefore, often the installation takes place on the roof of a building or on a high mast.

Finished wind turbine blades

Instructions for making a smokehouse from a barrel are contained in our next article.

Creating blades in stages

When designing blades yourself, consider the following:

First you need to decide on the shape of the blade. For a home horizontal wind generator, the shape of the wing is considered more successful. Due to its structure, it has less aerodynamic drag. This effect is created due to the difference in the areas of the outer and inner surfaces of the element, and therefore there is a difference in air pressure on the sides. The sail shape has more drag and is therefore less efficient.

This is what wind resistance looks like with different blade models

Next, you need to decide on the number of blades. For areas where there are constant winds, high-speed wind turbines can be used. 2-3 blades are enough for such devices for maximum engine spin-up. When using such a device in a calm area, it will be ineffective, and will simply stand idle in calm weather. Another disadvantage of three-bladed wind turbines is high level noise that sounds like a helicopter. This installation is not recommended near densely populated houses.

For our latitudes, with weak and medium winds, five- and six-blade windmills are better suited, which will allow them to capture a weak wind flow and maintain stable engine operation.

Calculation of the power of the wind device. It is impossible to calculate the exact figure, since the power will directly depend on the weather and wind movement. But there is a direct relationship between the diameter of the wind wheel with the number of blades and the power of the equipment.

The data are given for an average wind speed of 4 m/s (click on the picture to enlarge)

Having dealt with the data in the table and understanding the relationship, you can use the creation of the correct helical wheel to influence the power of the future design

The choice of material for creating the blades. The choice of materials for creating blades is quite wide: PVC, fiberglass, aluminum, etc. However, each of them has its pros and cons. Let us dwell on the choice of material in more detail.

Fiberglass wind turbine blades

PVC pipe blades

When selecting right size and pipe thickness, the resulting wheel will have high strength and efficiency. It should be borne in mind that with strong gusts of wind, plastic of insufficient thickness may not withstand the load, and shatter into small pieces.

In order to secure the design, it is better to reduce the length of the blades and increase their number to 6. To obtain such a number of parts, one pipe is just enough.

To create a blade, you need to take a pipe with a minimum wall thickness of 4 mm and a diameter of 160 mm, and mark future elements using a ready-made template and marker.

In order to avoid mistakes in independent calculations, it is better to use a ready-made template that can be easily found on the Internet. Because you can’t do without special knowledge in this matter.

After cutting the pipe, the resulting elements must be sanded and rounded at the edges. To connect the blades, a homemade steel assembly is made, with sufficient thickness and strength.

aluminum blades

Such a blade is stronger and heavier, which means that the entire structure holding the propeller must be more massive and stable. The subsequent balancing of the wheel should also be treated with increased attention.

Drawing of a standard aluminum element for a six-blade wheel

According to the presented template, 6 identical elements are cut out of an aluminum sheet, to inside which need to be welded threaded bushings for further fastening.

Studs must be welded to the connecting node, which will be connected to the bushings prepared on the blades.

In order to improve the aerodynamic properties of such a blade, it must be given correct form. To do this, it must be rolled into a shallow groove so that an angle of 10 degrees is formed between the scroll axis and the longitudinal axis of the workpiece.

fiberglass blades

The advantage of this material is the optimal ratio of weight and strength, in total with aerodynamic properties. But working with fiberglass requires special skill and great professionalism, so it is difficult to create such a product at home.

fiberglass blades

It can be concluded that the most suitable material for self-assembly of the wind wheel - PVC pipe. It combines strength, lightness and good aerodynamic characteristics. Moreover, this is a very affordable material, and even a beginner will cope with the work.

How to make blades for a wind generator with your own hands
Home wind farms are an independent alternative way to generate electricity. The installation of such equipment can significantly reduce the cost of electricity. This article will consider a step-by-step plan for making wind turbine blades with your own hands.

Owners of country houses have a desire to make their buildings unique, with a twist and a memorable facade design. There are many ways to achieve the goal, they differ both in the complexity of engineering solutions and in cost.

Airplane - weather vane

In this article we will focus on one of the cheapest, but very effective methods improvements appearance buildings - installation of a weather vane with a propeller.

Weathercocks can look like models of airplanes, animals, have an original shape, etc. These are design characteristics, they do not affect the functional parameters of products. The main differences between them are in the materials of manufacture.

What can be used for these purposes?

Production material	Description of technical and operational characteristics
	Not a very common manufacturing option, it is now quite rare. Reason - actual performance characteristics do not meet modern requirements. Impregnation of the material with compositions only slightly increases the time of use of the products. In addition, the weather vane has some elements that are in constant motion. The tree does not have high wear resistance; special technical measures must be taken to increase the service life. This can only be done by a professional master.
	A fairly common manufacturing option, a significant operational drawback - the surface must be reliably protected from rust. Another problem is that for the manufacture of a metal structure, you need to have special equipment and tools. Excellent indicators have weathercocks from the alloyed stainless steel.
	Beautiful, strong and durable material. You can buy sheet copper in ordinary stores building materials. Copper plates are thin, they can be cut with ordinary scissors, which greatly facilitates the manufacturing process. The copper weather vane ages over time and acquires a very prestigious look.
	Original modern material, is quite popular. Plastic is very technological, it is easy to saw and cut, when heated it takes on various shapes and after cooling it retains them. The disadvantage is that low strength indicators reduce the life of such products.
	The most unfortunate choice, in terms of all operational and physical characteristics, is inferior to the above materials. Such a weather vane is not recommended to be installed on the roof ridge, dismantling is too complicated, and this will have to be done in a few months.

The main criterion for choosing a material should be the ultimate goal of manufacturing a weather vane and the place of its installation. If it is placed on the roof, then you should choose durable, beautiful and weather-resistant materials. All moving elements must be made with a large margin of safety; no one wants to climb the roof to repair the device every month.

Prices for various types of weather vanes

Making a copper weather vane

The size of the weather vane is 18×29 cm, the material of manufacture is copper and brass. There is no point in making a large weather vane, heavy structures only complicate the production process and reduce reliability. As for the design look, there are also strict restrictions on the dimensions of the elements installed on the roof ridge. And the last. We must not forget that the weather vane will still have to be fixed, and these are extra holes in the roof that do not benefit her.

For the manufacture of a weather vane, you can use improvised materials left over from other works and old items. In our case, a piece of fluoroplastic, a copper rod Ø 6 mm, an unnecessary old brass candlestick and an oil pump plunger are used. Fluoroplastic is used as a bearing - it is not afraid of moisture, has high wear resistance and quite sufficient physical strength.

Step 1. Find on the Internet and print a picture or ornament for a weather vane.

Practical advice. No need to choose complex or small drawings, they are invisible from a great distance. In addition, such contours are very difficult to cut, you should not create additional problems for yourself. Moreover, no positive effect the result will not work.

Step 2 Glue the patterned paper onto the copper plate. To do this, you can use special tapes. They are glued to the paper, and then the protective coatings are removed from them on the reverse side. After removal, the adhesive remains on the paper, it can be fixed on any object.

Step 3 Cut out the outline of the weather vane with special or ordinary scissors. A thin copper plate is cut easily.

Step 4 Fasten the weather vane blank between two pieces of even boards, firmly squeeze them with clamps. Bend one end at a right angle with a mallet. The length of the hem is approximately 2-3mm. It is needed so that during the further cutting of the contour, the current copper plate is not deformed. In the future, the tube is soldered to the hem.

Step 5 Start cutting out small details of the pattern. This should be done with needle files, having previously drilled holes of the appropriate diameter.

Do not rush, work very carefully. It is not a problem if the pattern is slightly disturbed and changed, this is an exclusive and individual solution. The main thing is that the plane of the plate does not have critical deformations.

Step 6 Remove the paper from the surface of the plate and carefully clean it with a fine sandpaper.

Step 7 Increase the hardness of platinum, it is very thin and cannot withstand strong gusts of wind. To do this, it is better to use brass wire with a diameter of 2–4 mm. The line should approximately correspond to two lengths of the weather vane. Bend the wire in an arc in the center, it is better to use a circle of the appropriate diameter as a template.

Put the workpiece on the plate, correct the shape of the wire if necessary. Press the parts with any heavy object, treat the soldering place with a special flux and connect the two elements. You can solder with both an ordinary electric and a modern gas soldering iron. The second tool is much easier and faster to work with.

On this, the weather vane sail itself is ready, it is necessary to start manufacturing other parts. Let's say right away that these processes are much more complicated than the first.

Manufacturing of guide structures

You will need to make your own decisions about what products you have, what you can use and how. We have already mentioned that in our case, some parts of the weather vane are made from old candlesticks.

Step 1. Unscrew the upper part of the candlestick from the stand, hold it in a vise and solder a piece to it copper tube.

Its length should be 1-2 cm more than the width of the sail, in our case 20 cm. The soldering process is standard, always follow the safety rules. The fact is that a fairly aggressive flux is used to solder copper, it must dissolve the upper film of metal oxide. Otherwise, the solder will not bond with the copper.

Step 2 Put a decorative tip on the end. It is advisable to carve it separately from a suitable alloy. If this is not possible, then use the parts at hand from other products.

Step 3 On one side of the copper tube, solder the weather vane sail, and on the other side, specially bent copper wires. The sail is fixed to the previously bent side, and the pieces of wire are located exactly along the line of symmetry on the opposite side. In the final form, all elements are located strictly in the same plane, they should look symmetrical and beautiful. If you wish, create various patterns, bend the wire in spirals, create additional decorative elements.

Step 4 Flare one end of the copper tube. This is done with a hammer and a steel cone. Install the tube in a vertical position on the cone and flare with a hammer from the opposite side. Try to make everything look beautiful, do not increase the diameter too much. Otherwise, the copper may crack, you will have to cut off the damaged end and start work again.

Step 5 Carefully cut off the end of the tube opposite from the flare. It is better to use a special cutter, it leaves a perfectly even and perpendicular to the axis cut. But not everyone has such a tool, only professionals need it. You can remove the end of the tube with an ordinary hacksaw for metal, and then fix the ends with files. The fact is that it is very difficult to achieve an ideal cut only with a canvas, in most cases you will have to work with files.

Step 6 Insert the coupling into the flared tube, drive it tightly inward. Next, you should solder another piece, its length is already much longer. This tube serves as a housing for the inner axle and PTFE bushing. Work very carefully, the axes of all tubes must be located strictly on the same line. During soldering, constantly check the position of the elements, correct them if necessary.

Step 7 Insert a specially prepared piece of PTFE into the lower end. It should fit snugly into the tube, not wobble or fall out. The PTFE must have a hole into which the oil pump plunger is inserted.

Connection of PTFE and tube, as well as a plunger (pictured right)

Make the hole 0.1 mm smaller than the plunger diameter, it is necessary to achieve a connection with a slight interference. The plunger is made of very strong alloyed stainless steel, which ensures long and reliable operation of this element. We remind you once again that all individual parts must lie on one straight line, the performance of the weather vane depends on this.

Step 8 Assemble the weather vane, insert all parts into place and check its rotation. It should be free and as light as possible.

If desired, copper can be artificially aged, for this sulfuric liver is used. The patination process is accompanied by the release of harmful chemical compounds, you need to work in a respirator and rubber gloves.

"Sulfur liver" is a brown mass obtained by sintering 1 g of sulfur with 2 g of potash or caustic soda. Sinter the mixture in an iron spoon over low heat.

Put a propeller on the weather vane, we will describe how it is done a little lower.

Now you can install the finished weather vane on the roof ridge. Decide on a place, drill holes of a suitable diameter. If you have a metal bar on your skate, then the work is much simpler. For ceramic coatings you will have to come up with other options that are safe for the roof and reliable fasteners. The drilled hole is sealed with a strip of tape impregnated with bitumen, and only then a weather vane is tightly inserted into it.

Important. The design of the weather vane cannot be securely held only by a hole in a metal sheet with a thickness of approximately 0.45 mm. If the roof is not insulated, then from the side of the attic it is necessary to install additional elements for fixation. If the attic is of the attic type, then it is impossible to get to the base of the weather vane from the back of the roof; special platforms must be made to securely fix the product on the metal roof.

Prices for various types of soldering irons

soldering iron

Making a weather vane from sheet steel

The process of manufacturing a weather vane from sheet steel does not have any special differences from the above, the difference is only in the technologies used.

Sheet steel is much stronger than copper, which causes problems when cutting a pattern on a wind vane sail.

It is best to use a manual plasma cutter, it is easy to work with such a device, it gives smooth edges. But the drawing needs to be transferred from paper to a metal plate, this can be done with a felt-tip pen.

Accordingly, all assembly work is done by welding, then the seams are cleaned, the metal weather vane is covered with protective anti-corrosion coatings.

As mentioned above, it is better to use stainless steel sheets for such products. After cutting out the pattern, metal streaks appear on the reverse side of the sheet, they must be removed. Use an ordinary grinder with a thick abrasive disc. Not thin for cutting metal, but thick. The thin one can crack, causing very serious injury.

Metal, plastic or wooden propellers are put on the front of the weather vanes.

How to make a propeller

The wooden propeller screw is made from hornbeam, birch or pear. You can also use coniferous wood, but they are quite soft and wear out quickly. The propeller is made in several stages.

Step 1. Draw a top view on the workpiece, for this, use a pre-made template. In the center, drill a hole for the shaft, the diameters should allow free rotation.

Step 2 Electric jigsaw cut the workpiece, mark on it the angles of the twist of the blades. They affect the thrust force, as the values increase, the propeller will rotate from the slightest air movements.

Step 3 Draw a side view, remove the excess thickness of the tree with a knife or planer. Treat the transition point of the blades to the center of the core.

The profile must be plano-convex

Step 4 After cutting, smooth the surfaces with sandpaper. Balance on a horizontal wire.

Now it remains to cover the surfaces of the propeller with a durable varnish for outdoor use and install it on the weather vane.

Prices for popular models of jigsaws

Electric jigsaw

Video - How to make a weather vane

The decoration of the roof can be not only a figured weather vane, but also a simple cap crowning the chimney. Such products are necessary so that dirt, debris, moisture does not get inside the chimney channel, and birds do not build nests on the pipe. About,

Magazine "Modelist-Constructor"

Article from the magazine Modelist-Constructor No. 1 for 1974.
Scan: Petrovich.

Aerosleighs, airboats, all kinds of hovercraft, acranoplanes, microplanes and microautogyros, various fan installations and other machines cannot operate without a propeller (propeller).

Therefore, every enthusiast of technical creativity, who has decided to build one of these machines, must learn how to make good propellers. And since in amateur conditions they are easiest to make from wood, we will only talk about wooden propellers.

However, it should be noted that for wood (if it turns out to be successful), completely similar screws can be made from fiberglass (by molding into a matrix) or metal (casting).

Due to their availability, two-bladed propellers made from a single piece of wood are most widely used (Fig. 1).

Three- and four-bladed propellers are more difficult to manufacture.

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Rice. one . Two-bladed wooden propellers from a whole piece of wood: 1 - blade, 2 - hub, 3 - front flange, 4 - hub stud nuts, 5 - castellated shaft toe nut, 6 - shaft, 7 - rear flange, 8 - studs.

MATERIAL SELECTION

What is the best wood to make a screw? This question is often asked by readers. We answer: the choice of wood primarily depends on the purpose and size of the screw.

Propellers designed for engines of higher power (about 15-30 hp) can also be made from solid hardwood bars, but the requirements for wood quality in this case increase. When choosing a blank, one should pay attention to the location of annual rings in the thickness of the bar (it is clearly visible along the end, Fig. 2-A), giving preference to bars with a horizontal or inclined arrangement of layers, sawn from that part of the trunk that is closer to the bark. Naturally, the workpiece should not have knots, crooked layers and other defects.

If it was not possible to find a monolithic bar of suitable quality, you will have to glue the workpiece from several thinner boards, each 12-15 mm thick. This method of manufacturing propellers was widespread at the dawn of the development of aviation, and it can be called "classical". For reasons of strength, it is recommended to use planks of wood different breeds(for example, birch and mahogany, birch and red beech, birch and ash), having mutually intersecting layers (Fig. 2-B). Screws made from glued blanks have a very beautiful appearance after final processing.

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Rice. 2. Propeller blanks: A - from a whole piece of wood: 1 - sapwood part of the trunk, 2 - location of the blank; B - a blank glued from several boards into a rectangular package: 1 - mahogany or red beech; 2 - birch or maple.

Some experienced specialists glue blanks from multilayer air plywood of the BS-1 brand, 10-12 mm thick, assembling a package of the required dimensions from it. However, we cannot recommend this method to a wide circle of amateurs: veneer layers located across the screw can form irregularities that are difficult to eliminate and degrade the quality of the product during processing. The ends of the propeller blades made of plywood are very fragile. In addition, a high-speed propeller at the root of the blades has a very large centrifugal force, reaching in some cases up to a ton or more, and in plywood, the transverse layers do not work to break. Therefore, plywood can only be used after calculating the area of the root section of the blade (1 cm2 of plywood can withstand a break of about 100 kg, and 1 cm2 of pine - 320 kg.) The screws have to be thickened, and this worsens the aerodynamic quality.

In some cases, the attack edge of the propeller is covered with a strip of thin brass, the so-called fitting. It is attached to the edge with small screws, the heads of which, after stripping, are soldered with tin to prevent self-loosening.

MANUFACTURING SEQUENCE

According to the propeller drawing, first of all, it is necessary to make metal or plywood templates - one top view template (Fig. 3-A), one side view template and twelve blade profile templates that will be needed to check the screw on the slipway.

The screw blank (bar) must be carefully planed off, observing the size on all four sides. Then the center lines are applied, the contours of the side view template (Fig. 3-B) and excess wood is removed, first with a small ax, then with a planer and rasp. The next operation is processing along the contour of the top view. After applying the blade template to the workpiece (Fig. 3-B) and temporarily strengthening it with a nail in the center of the sleeve, circle the template with a pencil. Then the template is rotated strictly by 180 ° and the second blade is circled. Excess wood is removed on a band saw; This work must be done very accurately, so you should not rush.

The product acquired the shape of a screw (Fig. 3-D). Now the most important part of the work begins - giving the blades the desired aerodynamic profile. It should be remembered that one side of the blade is flat, the other is convex.

The main tool for giving the blades the desired profile is a sharply honed, well-set ax. This does not mean at all that the work performed is "clumsy": miracles can be done with an ax. It is enough to recall the famous Kizhi!

The wood is removed sequentially and slowly, first making small short nates to avoid splitting along the layer (Fig. 3-D). It is also useful to have a small two-handed shavings. The figure shows how you can speed up and facilitate the work of trimming the profile part of the blade by making several cuts with a fine-toothed hacksaw. When performing this operation, one must be very careful not to cut deeper than required.

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Rice. Fig. 3. The screw manufacturing sequence: A - templates (top view and side view); B - marking the bar-blank according to the side view template; B - marking the workpiece according to the top view template; G - workpiece after processing according to templates; D - processing of the blades along the profile (lower, flat part); E - processing of the upper, convex part of the blade.

After rough processing of the blades, the propeller is brought to condition with planers and rasps with a check in the slipway (Fig. 4-A).

To make a slipway (Fig. 4), you need to find a board equal in length to the screw and thick enough so that you can make cross cuts 20 mm deep in it to install templates. The central rod of the slipway is made of hard wood, its diameter must match the diameter of the hole in the screw hub. The rod is glued strictly perpendicular to the surface of the slipway. Putting a screw on it, determine the amount of wood that needs to be removed to match the blade to the profile templates. When doing this work for the first time, you need to be very patient and careful. The skill is not acquired immediately.

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Rice. Fig. 4. The slipway and templates of the blade profiles: A - installation of templates in the slipway; B - checking the processed blade with templates and counter-templates.

After the lower (flat) surface of the blade is finished according to the templates, finishing of the upper (convex) surface begins. Verification is carried out using counter-patterns, as shown in Figure 4-B. The quality of the screw depends on the thoroughness of this operation. If it suddenly turns out that one blade turned out to be a little thinner than the other - and this often happens with inexperienced craftsmen - you will have to correspondingly reduce the thickness of the opposite blade, otherwise both the weight and aerodynamic balance of the propeller will be violated. Minor flaws can be corrected by sticking pieces of fiberglass (“patches”) or grease with small sawdust mixed with epoxy resin (this mastic is colloquially called bread).

When cleaning the surface of a wooden screw, the direction of the wood fibers should be taken into account; planing, scraping and sanding can only be carried out “on a layer” in order to avoid scuffing and the formation of rough areas. In some cases, in addition to the cycle, glass fragments can be a good help in finishing the screw.

Experienced carpenters, after sanding, rub the surface with a smooth, well-polished metal object, pressing hard on it. By this they compact the surface layer and “smooth out” the smallest scratches remaining on it.

BALANCING

The manufactured screw must be carefully balanced, that is, brought to such a state that the weight of its blades is exactly the same. Otherwise, when the screw rotates, shaking occurs, which can lead to the destruction of vital components of the entire machine.

Figure 5 shows the simplest device for balancing screws. It allows you to balance with an accuracy of 1 g - this is practically enough in amateur conditions.

Practice has shown that even with very careful manufacture of the propeller, the weight of the blades is not the same. This happens for various reasons: sometimes due to the different specific gravity of the butt and upper parts of the bar from which the screw is made, or the different density of the layers, local knotting, etc.

How to be in this case? It is impossible to adjust the blades by weight, cutting some amount of wood from a heavier one. It is necessary to make the lighter blade heavier by riveting pieces of lead into it (Fig. 6). Balancing can be considered complete when the propeller remains stationary in any position of the blades relative to the balancing device.

No less dangerous is the beating of the screw. The scheme for checking the propeller for runout is shown in Figure 7. When rotating on the axis, each blade should pass at the same distance from the control plane or angle.

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Rice. 5. The simplest device for checking the balance of the screw - using two carefully aligned boards and an axial bushing.

Rice. 6. Balancing the screw by riveting pieces of lead into a lighter blade: A - determining the imbalance with the help of coins; B - embedding a piece of lead of equal weight on an equal shoulder (slightly countersink the hole on both sides); B - view of the lead rod after riveting.

Rice. 7. Scheme for checking the screw for runout.

FINISHING AND PAINTING OF THE SCREW

A finished and carefully balanced screw must be painted or varnished to protect it from atmospheric influences, as well as to protect it from fuels and lubricants.

For applying paint or varnish, it is best to use a spray gun powered by a compressor at a minimum pressure of 3-4 atm. This will make it possible to obtain an even and dense coating, unattainable with brush painting.

The best paints are epoxy. Glyphthalic, nitro- and nitro-glyphthalic or the more recent alkyd coatings can also be used. They are applied to a previously primed, carefully puttied and sanded surface. The interlayer drying corresponding to this or that paint is obligatory.

The best lacquer coating is the so-called "chemo-hardening" parquet lacquer. It adheres well to both clean wood and painted surfaces, giving it an elegant look and high mechanical strength.

Magazine "Modelist-Constructor"

Article from the magazine Modelist-Constructor No. 1 for 1974.
Scan: Petrovich.

Aerosleighs, airboats, all kinds of hovercraft, acranoplanes, microplanes and microautogyros, various fan installations and other machines cannot operate without a propeller (propeller).

However, it should be noted that for wood (if it turns out to be successful), completely similar screws can be made from fiberglass (by molding into a matrix) or metal (casting).

Due to their availability, two-bladed propellers made from a single piece of wood are most widely used (Fig. 1).

Three- and four-bladed propellers are more difficult to manufacture.

..
Rice. one . Two-bladed wooden propellers from a whole piece of wood: 1 - blade, 2 - hub, 3 - front flange, 4 - hub stud nuts, 5 - castellated shaft toe nut, 6 - shaft, 7 - rear flange, 8 - studs.

MATERIAL SELECTION

What is the best wood to make a screw? This question is often asked by readers. We answer: the choice of wood primarily depends on the purpose and size of the screw.

If it was not possible to find a monolithic bar of suitable quality, you will have to glue the workpiece from several thinner boards, each 12-15 mm thick. This method of manufacturing propellers was widespread at the dawn of the development of aviation, and it can be called "classical". For reasons of strength, it is recommended to use boards made of wood of different species (for example, birch and mahogany, birch and red beech, birch and ash), having mutually intersecting layers (Fig. 2-B). Screws made from glued blanks have a very beautiful appearance after final processing.

MANUFACTURING SEQUENCE

After rough processing of the blades, the propeller is brought to condition with planers and rasps with a check in the slipway (Fig. 4-A).

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Rice. Fig. 4. The slipway and templates of the blade profiles: A - installation of templates in the slipway; B - checking the processed blade with templates and counter-templates.

BALANCING

Figure 5 shows the simplest device for balancing screws. It allows you to balance with an accuracy of 1 g - this is practically enough in amateur conditions.

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Rice. 5. The simplest device for checking the balance of the screw - using two carefully aligned boards and an axial bushing.

Rice. 7. Scheme for checking the screw for runout.

FINISHING AND PAINTING OF THE SCREW

A finished and carefully balanced screw must be painted or varnished to protect it from atmospheric influences, as well as to protect it from fuels and lubricants.

The best lacquer coating is the so-called "chemo-hardening" parquet lacquer. It adheres well to both clean wood and painted surfaces, giving it an elegant look and high mechanical strength.