Wind Turbine Blade Making Part 1 of 7

Don't do this design. Do the part 6 design.
Part 5 shows it turning. However, the eight foot length needs
a wider seven inch width near the centre, instead of my four inches. Also, it has trouble starting to turn because of insufficient steep angle of attack near the centre.

This is helpful: http://www.windmission.dk/workshop/BasicBladeDesign/bladedesign.html

I am working on improving it by possibly adding two more
wide blade stubs to give starting torque. (Part 6 and beyond is coming soon). I've never seen that done before.

This website also helped me decipher what is wrong:
http://www3.telus.net/faheydumas/Wind_Turbine/1_Blades/Aero.html

I am carving an eight foot wind turbine blade from a cedar 2x4 by using a small circular saw and four templates of airfoil profiles. I chose profiles recommended by NREL at this web link: http://wind.nrel.gov/designcodes/papers/NREL%20Airfoil%20Families%20for%20HAW...

After I finished, I found this, and other, great links by searching "NREL S822":
http://wind.nrel.gov/airfoils/Shapes/S823_Shape.html

Here is the free airfoil program which prints to real sizes, not exactly NREL:
http://www.rc-soar.com/hardsoft/profilerev.htm
I used 3.67" chord parameter to make it fit a 2x4 plus these:

radius from centre
1ft, thickness 21.0%, camber, 1.16, washout 10 degrees
2ft, thickness 19.7%, camber, 1.00, washout 6.25 degrees
3ft, thickness 17.3%, camber, 1.89, washout -2.5 degrees
4ft, thickness 16.0%, camber, 1.89 , washout -1.0 degree
(I used negative degrees for the last two and turned the paper over
to reverse the slope because the camber was closer that way).

After printing them, I hand drew changes to approximate S822 and S823.

Here is where I grabbed the angle suggestions from root to tip: http://www.warlock.com.au/tools/bladecalc.php
and here:
http://www.windmission.dk/workshop/BasicBladeDesign/bladedesign.html
http://www.windstuffnow.com/main/blade_design_help.htm

It took me one hour per foot using this method, plus two hours belt sanding. I should have used a router.

The blade weighs only 3.7 pounds.

This is a good lecture about why we use airfoil shapes:
http://www.youtube.com/watch?v=GExTwRNkQBg&

Here are my profiles, which you can print and tape to wood to cut them out:

http://img140.imageshack.us/img140/7276/profile1ft001.png
http://img51.imageshack.us/img51/5453/profile2ft001.png
http://img819.imageshack.us/img819/7262/profile3ft001.png
http://img534.imageshack.us/img534/2121/profile4ft001.png

Check out muddymuddymuddmann for a 2x4 blade which works because the total length is shorter.

This might be useful:
http://www.mh-aerotools.de/airfoils/javafoil.htm

Category:

Science & Technology

Tags:

• wind
• turbine
• windmill
• blade
• electricity
• generator
• mill

[definitionofis]

@TeacherPhilEnglish I learned a lot since writing comments here three months ago. I don't have as much wind as I thought. I added two blades to make it four and it turns very easily, with no load now.

I have no hope of generating much electricity without a tower.

Here is my latest video where I see it turning for the first time, WITH the generator attached:

youtube com watch?v=zkVVGsB0bzg

[definitionofis]

A blade should start turning at 12 km/h (7 mph) although there is no power at that speed. I expect only 60 watts for my blade at 16 km/h (10 mph) and 200 watts at (24 km/h) 15 mph, and 480 watts at 32 km/h (20 mph). Every double in speed increases potential power, eight times.

Blade design is complex. Some blades work better in high winds. I'm aiming for low winds with a big blade. That's why I did not carve it by eye.

[TeacherPhilEnglish]

@definitionofis They have windmills here near the bay and they don't really turn even with about 20kmh wind. I think they need help to start moving with heavy wind. Your light cedar might do the trick.

[definitionofis]

@TeacherPhilEnglish I have 15 mph average. It is better than some locations because it is near a lake. It is in the suburbs though. So I can't put up a tower.

There is a funnel effect, which I identified over the years, between some large houses. So I am going to fix mount it in one direction. I have a broken high efficiency furnace motor, which I am going to attach to it. It is very good at generating electricity. I removed the broken controller.

[TeacherPhilEnglish]

@definitionofis you can get it to work. I would just draw one sketch on each end and just plane it down to size freehand. Do you have lots of wind?

[definitionofis]

@TeacherPhilEnglish If this does not work, I'll do more sanding until it works (LOL) or I'll buy this one: magnet4sale com/8.5-Commercial-Grade-High-­Efficient-and-Reinforced-Wind-­Generator-Blades html

(Mine is 1/3 the weight).

[TeacherPhilEnglish]

lot of work wow