The use of alternative energy sources is one of the main trends of our time. Clean and affordable wind energy can be converted to electricity even in your home if you build a windmill and connect it to a generator.
You can build blades for a wind generator with your own hands from ordinary materials, without using special equipment. We will tell you which shape of the blades is more effective, and help you choose the right drawing for a wind farm.
How does a simple wind generator work?
A wind generator is a device that allows you to convert wind energy into electricity.
The principle of its operation lies in the fact that the wind rotates the blades, sets in motion a shaft along which the rotation enters the generator through a gearbox that increases speed.
The operation of a wind power plant is estimated by KIEV - the coefficient of use of wind energy. When the wind wheel rotates quickly, it interacts with a large amount of wind, which means it takes more energy from it
Two main types of wind generators are divided:
- veterinary;
- horizontal.
Vertically oriented models are built so that the propeller axis is perpendicular to the ground. Thus, any movement of air masses, regardless of direction, sets the structure in motion.
Such versatility is a plus of this type of windmills, but they lose to horizontal models in terms of productivity and work efficiency
The horizontal wind generator resembles a weather vane. For the blades to rotate, the structure must be turned in the right direction, depending on the direction of air movement.
Special instruments are installed to control and capture changes in wind direction. Efficiency with this arrangement of the screw is much higher than with a vertical orientation. In domestic use, it is more rational to use wind generators of this type.
Which blade shape is optimal?
One of the main elements of a wind generator is a set of blades.
There are a number of factors associated with these details that affect the efficiency of the windmill:
- weight;
- the size;
- the form;
- material;
- quantity.
If you decide to design blades for a homemade windmill, you must definitely consider all these parameters. Some believe that the more wings there are on the generator propeller, the more wind energy can be obtained. In other words, the more the better.
However, this is not the case. Each individual part moves overcoming air resistance. Thus, a large number of blades on the screw requires a greater wind force to complete one revolution.
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Turbine-shaped blades of a windmill
Vertical arrangement of the blades
Custom Windmill
Ordinary vanes
In addition, too many wide wings can cause the formation of the so-called “air cap” in front of the propeller, when the air flow does not pass through the wind turbine, but bends around it.
Form is of great importance. The propeller speed depends on it. Poor flow results in vortices that inhibit the wind wheel.
The most effective is a single-blade wind generator. But to build and balance it with your own hands is very difficult. The design is unreliable, albeit with a high efficiency. According to the experience of many users and manufacturers of windmills, the most optimal model is a three-blade.
The weight of the blade depends on its size and the material from which it will be made. The size must be selected carefully, guided by the formulas for the calculations. Edging is best done so that there is a rounding on one side and the opposite side is sharp
Properly selected blade shape for a wind generator is the foundation of its good work.
For home manufacturing, the following options are suitable:
- sailing type;
- wing type.
The blades of the sailing type are simple wide stripes, like in a windmill. This model is the most obvious and easy to manufacture. However, its efficiency is so small that this form is practically not used in modern wind generators. The efficiency in this case is about 10-12%.
A much more effective form is the wing profile blades. The principles of aerodynamics are involved here, which fly huge planes into the air. A screw of this shape is easier to set in motion and rotates faster. Air flow significantly reduces the resistance that a wind turbine encounters in its path.
The correct profile should resemble the wing of an airplane. On one side, the blade has a thickening, and on the other, a gentle slope. Air masses flow around a part of this shape very smoothly
The efficiency of this model reaches a value of 30-35%. The good news is that you can build a wing blade with your own hands using a minimum of tools. All basic calculations and drawings can be easily adapted to your windmill and use free and clean wind energy without restrictions.
What do the blades make at home?
The materials that are suitable for the construction of a wind generator are, first of all, plastic, light metals, wood and a modern solution - fiberglass. The main question is how much labor and time are you willing to spend on making a windmill.
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Hard technology blades
Metal spiral turbine
Blades of a windmill from a polymer pipe
Assembling a windmill with plywood blades
PVC sewer pipes
The most popular and widespread material for the manufacture of plastic blades for a wind generator is an ordinary PVC sewer pipe. For most home generators with screw diameters up to 2 m, 160 mm pipes will suffice.
The advantages of this method include:
- low price;
- availability in any region;
- simplicity of work;
- a large number of diagrams and drawings on the Internet, a wide experience of use.
Pipes are different. This is known not only to those who make home-made wind farms, but to everyone who has encountered the installation of a sewer or water supply system. They differ in thickness, composition, manufacturer. The pipe is inexpensive, so you do not need to try to further reduce the cost of your windmill, saving on PVC pipes.
Poor material in plastic pipes can cause the blades to crack during the first test and all work will be wasted
First you need to decide on the pattern. There are many options, each form has its advantages and disadvantages. Perhaps it makes sense to experiment first before cutting out the final version.
Since the price of the pipes is low, and you can find them in any hardware store, this material is perfect for the first steps in modeling the blades. If something goes wrong, you can always buy another pipe and try again, the wallet will not suffer much from such experiments.
Experienced wind power users have noticed that it is better to use orange rather than gray pipes to make the blades for the wind generator. They hold their shape better, do not bend after wing formation and last longer
Amateur designers prefer PVC, since during the test, a broken blade can be replaced with a new one, made in 15 minutes right on the spot with a suitable pattern. Simple and fast, and most importantly - affordable.
Photo-instructions for the manufacture of blades of a windmill from polymer pipes will help to visually master the steps and sequence of the process:
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Step 1: Marking the outline of the blades of a windmill
Step 2: Open the blades with a blogger
Step 3: Marking the lug for mounting
Step 4: Cutting the protrusion and deburring
Step 5: Preparing Metal Plates
Step 6: Cutting the mounting plate into two parts
Step 7: Aligning Cut Plates
Step 8: Sanding the Cropped Side
All preparatory steps have been completed, now the blades must be attached to the part rotating after the wind:
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Having attached to the ledge on the blades a trimmed mounting plate, mark the points of the forthcoming fastening through the holes
We drill holes for installing fasteners by placing a piece of board or a block under the blade. To do this, it is better to take a drill with a diameter slightly smaller than the diameter of the screw leg
The remaining polymer shavings after drilling must be carefully removed from the holes, being careful not to tear so that the size of the mounting sockets increases
On the metal disk, mark the center where the anchor bolt will be installed, and draw an equilateral triangle, each vertex of which marks the position of the mounting plate
Glue the plates to the metal disk, placing them at the vertices of the triangle. This will facilitate our work during welding.
In the center of the disc, we position and weld a nut to insert an anchor bolt into it. The glued plates are welded with a convex seam
We fasten the blades cut from the pipes to the welded part. We install them so that the bend of all was directed to one side
We screw a nut on each screw on the back side. In order for the fasteners not to unscrew when the blades rotate, it is advisable to fix them by soldering or welding
Step 9: Marking the attachment points
Step 10: Drilling Mounting Holes
Step 11: Preparing the Holes for Assembly
Step 12: Marking the blade for installing the blades
Step 13: Bonding the plates before welding
Step 14: Preparing the Rotary Disc for Assembly
Step 15: Attaching the Plastic Blades
Step 16: Tighten the Screws
Aluminum - thin, light and expensive
Aluminum is a light and durable metal. It is traditionally used for the manufacture of blades for wind generators. Due to its light weight, if you give the plate the desired shape, the aerodynamic properties of the screw will be at a height.
The main loads that the windmill experiences during rotation are aimed at bending and breaking the blade. If during such work the plastic quickly cracks and fails, you can count on an aluminum screw for much longer.
However, if you compare aluminum and PVC pipes, metal plates will still be heavier. At high speeds, there is a high risk of damage not to the blade itself, but to the screw at the attachment point
Another disadvantage of aluminum parts is the complexity of manufacturing. If the PVC pipe has a bend that will be used to impart the aerodynamic properties of the blade, then aluminum is usually taken in the form of a sheet.
After cutting the part according to the pattern, which in itself is much more complicated than working with plastic, the resulting workpiece will still need to be rolled and give it the correct bend. At home and without a tool, this will not be so simple.
Instead of expensive aluminum, you can use scraps of roofing sheet or pieces of corrugated board remaining after installation:
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Step 1: Preparing the material for the manufacture of the blades
Step 2: Bending the edges of the blades
Step 3: Processing all the blades of a windmill
Step 4: Fit All Blades To Equal Size
Step 5: Shape the Gutters
Step 6: Marking the mounting holes
Step 7: Assembling the working part of the wind turbine
Step 8: Installing the wind generator on the mast
Fiberglass or fiberglass - for professionals
If you decide to approach the issue of creating a blade consciously and are ready to spend a lot of effort and nerves on it, fiberglass is suitable. If you have not dealt with wind generators before, starting an acquaintance with modeling a fiberglass windmill is not a good idea. Still, this process requires experience and practical skills.
The blade of several layers of fiberglass, bonded with epoxy glue, will be strong, light and reliable. With a large surface area, the part is hollow and almost weightless
For the manufacture of fiberglass is taken - a thin and durable material, which is produced in rolls. In addition to fiberglass, epoxy glue is useful for fixing layers.
Start work by creating a matrix. This is such a workpiece, which is a form for a future part.
The matrix can be made of wood: beams, boards or logs. The bulk silhouette of half of the blade is cut directly from the massif. Another option is a plastic mold
It is very difficult to make a blank on your own; you need to have a ready-made model of a blade made of wood or other material before your eyes, and only then a matrix for the part is cut out from this model. Such matrices need at least 2. But, having made a successful shape once, it can be used many times and thus built more than one windmill.
The bottom of the mold is thoroughly greased with wax. This is done so that the finished blade can be easily removed subsequently. Lay a layer of fiberglass, coat it with epoxy glue. The process is repeated several times until the workpiece reaches the desired thickness.
Then the glue should dry. Some recommend placing the mold in a vacuum bag and pumping air. So glue penetrates better into all layers of fiberglass, leaving no impregnated areas
When the epoxy glue dries, half of the part is carefully removed from the matrix. Do the same with the second half. The parts are glued together to form a hollow volumetric part. A lightweight, robust, aerodynamically shaped fiberglass blade is the pinnacle of excellence for a home enthusiast of wind farms.
Its main disadvantage is the difficulty of implementing the idea and a large amount of marriage at first, until the ideal matrix is obtained, and the creation algorithm is not refined.
Cheap and cheerful: a wooden part for a wind wheel
A wooden blade is an old-fashioned method that is easy to implement but ineffective at today's level of electricity consumption. You can make a detail from a solid board of light wood, such as pine. It is important to choose a well-dried wooden blank.
If the tree is damp, in the process of drying the screw can “lead” and it is deformed. And the weight of a wet tree is significantly higher than dry
It is necessary to choose a suitable shape, but take into account the fact that the wooden blade will not be a thin plate, like aluminum or plastic, but a three-dimensional structure. Therefore, giving the workpiece a little shape, you need to understand the principles of aerodynamics and imagine the shape of the blade in all three dimensions.
The final look of the tree will have a plane, preferably electro. For durability, the wood is treated with an antiseptic protective varnish or paint.
The main disadvantage of this design is the large weight of the screw. In order to budge this colossus, the wind must be strong enough, which is difficult in principle. However, wood is an accessible material. Boards suitable for creating a wind turbine screw can be found right in your yard without spending a dime. And this is the main advantage of wood in this case.
The efficiency of a wooden blade tends to zero. As a rule, the time and effort that goes into creating such a windmill is not worth the result, expressed in watts.However, as a training model or a test copy, a wooden part is quite the place to be. And the weather vane with wooden blades looks spectacular on the site.
The following selection of photographs will introduce the steps of making a windmill with blades cut out of plywood:
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We remove the generator from the used bicycle and drill holes in it for fastening the working part of the windmill - a plywood disk with blades
On the plywood sheet, we draw the blades of the future wind generator. In order to reduce the consumption of material, it is better to arrange them not as shown in the photo, but to direct the base in opposite directions
First, we draw all the details of the working part of the plywood windmill on paper, then transfer it to the plywood sheet.
In accordance with the marking, first we cut out the parts roughly with a jigsaw, then we finish it manually as necessary
Given the working conditions of the assembled mini-power plant, we process it before assembly. We cover with antiseptic impregnation and a flame retardant
We fasten pieces of the bar cut at one angle to the central disk, to which all details of the plywood screw of the wind generator will be attached
We fasten plywood blades and a generator from a used bike to the pegs mounted on the disk
After assembling the working part of the wind generator, we check how freely the disk with the generator rotates. If something interferes, grind, correct
Step 1: Preparing the Generator from the Bicycle
Step 2: applying the blade template
Step 3: Drawings of Windmill Parts Templates
Step 4: Sawing the components of the working part
Step 5: Antiseptic Processing of Parts
Step 6: Attaching the Beveled Pegs
Step 7: Installing the Bicycle Generator
Step 8: Checking the Free Rotation of the Screw
The working part is ready and tested for operability, which means that it remains only to paint and fasten it to the mast:
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Step 9: Securing the Propeller
Step 10: Primer Processing
Step 11: painting the details of the windmill
Step 12: Attaching the Working Part to the Mast
Drawings and examples of blades
It is very difficult to make the correct calculation of the screw of the wind generator without knowing the main parameters that are displayed in the formula, as well as having no idea how these parameters affect the operation of the wind turbine.
It is better not to waste your time if there is no desire to delve into the basics of aerodynamics. Ready-made blueprints with preset indicators will help you choose the right blade for a wind farm.
Drawing of a blade for a two-blade propeller. It is made of a sewer pipe of 110 diameter. The diameter of the wind turbine screw in these calculations is 1 m
Such a small wind generator will not be able to provide you with high power. Most likely, you can hardly squeeze more than 50 watts out of this design. However, a two-bladed propeller made of light and thin PVC pipe will give a high rotation speed and ensure the operation of the windmill even with a small wind.
Drawing of a blade for a three-blade propeller of a wind generator from a pipe of 160 mm diameter. The estimated speed in this option is 5 with a wind of 5 m / s
A three-blade propeller of this shape can be used for more powerful units, approximately 150 W at 12 V. The diameter of the entire propeller in this model reaches 1.5 m. The wind wheel will rotate quickly and easily start to move. Three-winged windmills are most common in home power plants.
Drawing of a homemade blade for a 5-blade propeller of a wind generator. It is made of PVC pipe with a diameter of 160 mm. Estimated Speed - 4
Such a five-blade propeller can produce up to 225 revolutions per minute at a design wind speed of 5 m / s. To build a blade according to the proposed drawings, you need to transfer the coordinates of each point from the columns "Front / Rear Pattern Coordinates" to the surface of the plastic sewer pipe.
According to the table below, you can calculate the diameter of the windmill with 2-16 blades. In this case, you can choose the size taking into account the desired output power.
The table shows that the more wings the wind generator has, the less their length must be to obtain a current of the same power
As practice shows, servicing a wind generator more than 2 meters in diameter is quite difficult. If, according to the table, you need a larger windmill, consider increasing the number of blades.
The rules and principles of calculating a wind generator will be introduced by an article that outlines the process of making calculations step by step.
Performing Wind Turbine Balancing
Balancing the blades of a wind generator will help make its operation as efficient as possible. To balance, you need to find a room where there is no wind or draft. Of course, for a wind wheel more than 2 m in diameter, it will be difficult to find such a room.
The blades are assembled into a finished structure and installed in working position. The axis should be located strictly horizontally, in level. The plane in which the screw will rotate must be set strictly vertically, perpendicular to the axis and ground level.
The screw, which does not move, must be rotated 360 / x degrees, where x = the number of blades. Ideally, a balanced windmill will not deviate by 1 degree, but will remain motionless. If the blade turned under its own weight, it needs to be slightly corrected, reduce weight on one side, eliminate deviation from the axis.
The process is repeated until the screw is completely motionless in any position. It is important that there is no wind during balancing. This may distort test results.
It is also important to ensure that all parts rotate strictly in the same plane. To check at a distance of 2 mm on both sides of one of the blades set the control plate. During movement, no part of the screw should touch the plate.
To operate a wind generator with manufactured blades, it will be necessary to assemble a system that accumulates the received energy, saves it and transfers it to the consumer. One of the components of the system is the controller. You will learn how to make a controller for a wind turbine by reading the article recommended by us.
To build a windmill with your own hands from improvised materials is quite possible. If you start with simpler models, then the first attempt is likely to be successful. With experience, take on more complex ideas to get the most efficient and powerful wind generator.
Video # 1. How to make a windmill from PVC pipes:
Video # 2. DIY wind generator:
Video # 3. Galvanized steel windmill:
If you want to use clean and safe wind energy for household needs and do not plan to spend a lot of money on the purchase of expensive equipment, homemade blades made of ordinary materials would be a good idea. Do not be afraid of experiments, and you will be able to further improve existing models of propellers of a windmill.
Do you want to tell how you personally made blades for a windmill, which provides cottage with electricity? Would you like to share useful information with site visitors or ask a question? Please write comments in the block below.