This post is the third of a series of posts describing how to build a home made wind generator.

Check the first post on How To Build The Blades

Check the second post on What Materials To Use To Build The Blades

OK, Let’s get into how to cut the blades

Using a 4” to 12” sewer PVC pipe, you will cut it quartering the pipe, and then you will cut out one blade, and use it as a template for cutting out the others. That will leave you with 4 blades (3 plus one spare).We are going to build a 3 blade assembly. You can use a jigsaw to cut the pipe. See the figure below

Cutting the line with a jigsaw

The first step in cutting out the blades is to mark the pattern on the pipe with a marker. A tape measure and a large piece of project cardboard or Bristol board works great for transferring your pattern.

Notice that the centerline is slightly offset when cutting the first blade. This is to catch the wind more effectively. This first blade will be used as a template for the two other blades. See the figure below.

Notice that this example design pattern is set for a 10 inch pipe; in this way a 4 feet long blade will be on one side 7” wide and on the other 5”. If you use smaller or larger pipe diameter, just add or subtract one half inch of width for every 2 inches of pipe diameter as in the table below.

Pipe Diameter	Blade width at hub	Blade width at tip
4″	5.5″	3.5″
6″	6″	4″
8″	6.5″	4.5″
10″	7″	5″
12″	7.5″	5.5″

You can then do a little extra smoothing and shaping using a belt sander, palm sander or just sand paper on the cut edges to try to make them smoother. Smooth the sharp corners at the tip of the blades as well. This will serve to make the air flow better, thereby creating a better airfoil.

Wooden blades

Wood is also a recommended material to make blades and cedar is a nice wood. The Eastern White Cedar and Western Red Cedar have the same characteristics of lightness, super strength, flexibility and superb outdoor weathering capabilities.

For the building of your homemade wind generator blades you will want to find planed, finished lumber as thin as you can, preferably only one inch in thickness.

If you can’t find one inch lumber, ask at the lumber yard if they will cut it down to that size for you. The lumber piece should be 6 inches wide and 4 feet long for a single blade.

Use a jigsaw with a wood blade of fine teeth. Make each blade the same by copying the pattern 3 times.

Just put a small spacer piece on the leading side of each blade to tilt the blade in the direction of the wind. A slight tilt of 10 degrees is fine. Use a small piece of wood or angled metal to achieve the results you want to make that blade spin.

In our next post we will be discussing on how to build de hub that holds the blades together.

If you need a complete blueprint on how to build a home made wind generator CLICK HERE

If not, that´s Ok, just keep on checking our series of posts to get the whole picture to start your own project.

Filed Under: Alternative Energy Sources , Wind Power Tagged with Air Flow, Belt Sander, Blade Width, Bristol Board, Building A Home, Capabilities, Cardboard, Centerline, Cutting Blade, Flexibility, Hub, Inch Pipe, Jigsaw, Lumber, Marker, Outdoor Weathering, Palm Sander, Pipe Diameter, Pvc Pipe, Sand Paper, Sharp, Style Text, Table Style, Tape Measure, Wind Generator, Wind Generator Blades

To size a wind power renewable energy system, you first have to determine your energy budget.

In order to complete an energy budget you will need to know how much power typical appliances use. What follows is a chart to help you.

AC Appliances Typical Energy Usage in Watts

Toaster Oven 1500
VCR 35
Well Pump 800
Sewing Machine 87
Satellite TV 50
Refrigerator/freezer 460
Vacuum 1125
Circular Saw 1500
Hair Dryer 1500
Jigsaw 300
Computer 100
Laptop 60
Monitor 60
27” TV 200
DVD 14
Drill 800
Microwave oven 1245
Compact fluorescent 13
Battery Charger 25
Blender/mixer 350
Belt Sander 800
DC Appliance Energy Usage
Appliance Watts
Cell Phone 4
Motor (small) 65
Sunfrost refrigerator 13
Radio 15
Stereo 30
Water Pump 50
VCR 15
14” Color TV 75
Battery Charger 7
Inverter Standby 5
Halogen Light 20

Now that you know how much energy your appliances use you can figure out your total energy usage per week, and per month.

In order to do this, simply figure out how many hours each device is used each day. Multiply this number by the number of watts that device uses and you will come up with the watt-hours of usage. Add all of the totals together to come up with your total watt-hours of usage for the week, and for the month.

Keep these numbers with your notes; you will use them to design your charging capacity, battery bank and inverter sizing.

Figuring out your own energy usage

Take the numbers you got from your own appliances or use the numbers we provided and work out your own energy budget.

Example:

Appliance	Rated Wattage (A)	Hours Used per day (B)	Watt-Hours (A) x (B) per day
Satellite TV	50	5	250
Computer	100	5	500
Laptop	60	5	300
Stereo	30	2	60
Fuorescent light	13	10	130

Add as many items as it takes to complete your inventory. It should be noted that most households use approximately 20 Kilowatt hours per day on average.

Your new wind-powered renewable energy system would have to be very large to compensate for this high level of usage. A typical home made wind generator is only going to produce about 1 Kilowatt (1000 watts) of power. This is a wind turbine with blades 4 feet long, making a blade outside diameter of 8 feet.

Through conservation and buying newer more energy efficient appliances you can achieve the goal of living off the grid. It just takes some time and effort on your part. You can live on a total family usage of about 2 or 3 Kilowatt-hour per day and live a relatively normal life, with satellite TV, satellite internet, DVD’s, lights etc. It can be done.

Some questions answered

Once I know how much power I will need to run my home, how will I figure out how much power production I need?

Answer: You figured out how much power you use in the earlier exercise. You should be aiming for around 10 kilowatt hours per day. You could actually run your entire home on just under 3 kilowatt hours per day with energy conservation measures

The power formula goes like this:

System Power = (Wind Speed ^3) (Blade Diameter ^2) x .00478

Wind Speed is measured in miles per hour.

Blade Diameter is measured in feet.

Power is measured in Watts

It is easy to figure out your blade diameter. A widely used 8 foot blade diameter has been proved with great success.

To find your wind speed you will have to find a wind speed chart, or monitor your own wind speed for a while to obtain your own readings.

Here is a source of wind speed data.

World Wind Speed Data Maps

Let’s say your average wind speed is about 12 mph, which is pretty good. Plug that into your formula too. It would look something like this:

System Power = (12^3) (8^2) x .00478 = (1728) (64 ) x .00478
= 110592 x .00478 = 528 watts

Multiply this by 24 hours and you will have 12672 watt-hours, or about 1.2 kilowatt hours per day.

Wind speed has the greatest impact on power output since it is cubed in the previous formula. You can’t change wind speed though. You either have it or you don’t.

This brings up our next question.

Should I build one large wind generator, or several small ones?

Answer: Obviously blade diameter can have a huge impact on the amount of power that your homemade wind generator produces. There are a few concerns though. Yes, you could put up a homemade wind generator with a 20 foot blade diameter, but the forces of the wind at storm levels would demand a very substantial tower. Also, if you live in a populated area your neighbor might not appreciate a huge wind generator in your backyard. Ask first.

Some areas even have bylaws about this stuff, do some research first and find out what you can and cannot do.

Usually it is much easier to find towers for several smaller wind generators and parts to build them too. If you have areas on your property that are clear in different directions, put up several homemade wind generators to capture the wind more effectively from different directions with much smaller towers.

One final thing, when you have several homemade wind generators you can shut one down for cleaning or maintenance (or if a storm does this for you) and your other ones are still providing power.

A lot less work in the long run, and less headaches with a smaller system.

Get the full scoop on How to Build Your Own Home Made Wind Generator

Filed Under: Alternative Energy Sources , Wind Power Tagged with Ac Appliances, Battery Bank, Belt Sander, Budget Example, Capacity Battery, Energy Budget, Energy Usage, Halogen Light, Kilowatt Hours, Microwave Oven, Own Energy, Radio 15, Refrigerator Freezer, Renewable Energy System, Satellite Tv, Sewing Machine, Sunfrost, Table Style, Toaster Oven, Watt Hours, Wind Generator, Wind Power System