Model Wind Turbine

WT1
Background

 WT2  WT3
My inspiration for building a model wind turbine was after visiting the Kid Wind Project display during STEM Day at the Minnesota State Fair. Much like most of what I learned about mousetrap cars was from the Doc Fizzix website, I have learned much from Kid Wind Project website .  Large Wind Turbine Lewiston Minnesota After talking to the representative from KidWind Project at the state fair, I checked out their website and ordered a few items. Included in the order was the adjustable hub, small dc motor, and KidWind MINI2.0 model turbine.
WTLeft4 WTRight4
The first model wind turbine I constructed used the adjustable hub from Kidwind . More blades can be used and the pitch can easily be adjusted by tightening or loosening the hub clamping the dowels. Closer view of the Kidwind hub and motor. The knob in front tightens or loosens the hub halves that clamp the dowels. It is easy to change the pitch or number of blades.
 WTLeft5 WTRight5
Kidwind turbine with small diameter blades produces more voltage than the larger cardboard turbines I built. The blades are closer to ideal shape with higher pitch at the root and curving to flat at the blade tips. The circuit device is powered easily by the turbine with moderate wind. Normally directly behind the blades of a wind turbine is the alternator unit which produces alternating current (AC) electricity. Cost per kilowatt-hour for wind is comparable to other energy sources and is not projected to go up over time.

Small D.C. Motors as Generators

WTLeft6 WTRight6
In the simple model wind turbine a small DC motor acts as a generator to produce direct current (DC).
Small dc motors can often be found in toys or can be purchased where electronic components are sold. Purchasing small electric motors in quantities over 10 may reduce the price per motor.
WTLeft7 WTRight7
This motor came with pinion gear attached, it was possible to glue the hub over the gear without using sleeves.
This small motor included a bracket and short leads. The bracket made it easy to mount the motor to flat block with screws.
WTLeft8 WTRight8
Adding leads with alligator clips at the end makes it easy to connect to the meter probes. Cutting the leads in half and soldering to the motor, only half as many leads are needed.

Building the Model Wind Turbine

WTLeft9 WTRight9
I used just two types of wood; pine board labeled as 1” x 4” which are actually 3/4” x 3 ½”, try to find boards that are flat and minimum defects. I used 5/16” dowel for the tower. The dowels in the blades are 3/16”, I had those leftover from building kites.
Wood parts to build the model wind turbine. Additional holes will need to be drilled. The 3/16” dowels that are part of blades seen on top of the picture.

WTRight10

 
I created the hub for the model wind turbine using a hole saw but there are other methods of creating a hub. Using the hole saw drilled a hole in the middle for the shaft helped in creating a cradle for the motor to be fastened to.  It is for the creation of the motor cradle that I suggest cutting the hub before building the tower.
Mark out squares around the holes, this will be cut in half and used for the cradle if using a round motor.
WTLeft11 WTRight11
The easiest way to mark the three positions for the blade holes is by using a 3-blade model airplane prop as a guide. A protractor can be used to mark out 120 degree segments also.
Carefully drill the hub, the bit should just pass through the hole that passes through the
hub in horizontal direction.
WTLeft12 WTRight12
Draw a straight line through each hole and then
mark a spot ¼” away on back side, draw a diagonal line from front mark of line to back side mark.
Before creating the blades, check the fit of the dowels into the holes.
WTLeft13 WTLeft14
Make sure the dowels come straight out of the
holes also so that there is 120 angle between each dowel.
Use a vise to clamp wood parts while drilling.
WTLeft14 WTRight11
Glue the dowel into the base and makes sure it is vertical when looked at from all directions. Use a vise to clamp wood parts while drilling.
WTLeft15 WTRight15
Glue the mount or cradle for the motor to the top of the dowel support.
Bottom half of round motor is glued into cradle. The motor will be glued after the next step.
WTLeft16 WTRight16
The hole that runs through the hub will be
larger than the diameter of the electric motor
shaft that it has to mount to the hub. My solution has been to use sleeves
that fit over motor shaft to increase the
size until it fits snug inside the hole in the hub.
I used a combination of plastic and brass tubing to fit tight in the hole in the hub.
WTLeft17 WTRight17
Cutting short length of plastic tubing to create sleeve to go over motor shaft. Plastic sleeve fits over motor shaft very tight, no adhesive needed.

WTMiddle18Brass tubing sleeve fits over plastic sleeve and inside hole in wood hub.

Building the Blades

WTLeft19 WTRight19
Create a pattern to trace the other blades with. Trace around the blade pattern.
WTLeft20 WTRight20
Cut around the pattern that you traced, line down the center is the fold. Use a straight edge like a ruler and work a fold line in the cardboard.
WTLeft21 WTRight21
Bend curve shape into one half the cardboard after the fold, the other side should remain flat. Draw a straight line on one half of the cardboard to locate the dowel that connects the blade to the hub.
WTLeft22 WTRight22
Glue the dowel to the cardboard blade on the location line. Place the dowel on line and then apply glue around the edges.
WTLeft23 WTRight23
Seal the edges of cardboard. I later found that pressing a stiff ruler down along the area that was glued was a help to get a good glue joint. Three blades ready to be glued to the hub. The blade in the center has flat side showing.
WTLeft24 WTRight24
I did not get a good curve bend on this blade, looks more like a triangle. When you glue each blade in line it up with the line that is angled.
WTLeft25 WTRight25
Run drill through the shaft hole in the hub to clear out any glue. The sleeves are pushed together and glued if the
fit is not really snug. Make sure when blade assembly is pushed on that the flat side of blades are facing the
wind and the back of the blades do not rub against the
motor or stand.

Testing the Model Wind Turbine

WTLeft26 WTRight26
For testing your model wind turbine inside a fan works well, especially a fan with multiple speeds.
I started with the blades at full length and took a reading.
Although more POWER can normally produced with longer
efficient blades, more voltage can often be created with shorter blades. I find it interesting to start with longer blades , cut the length, and take new voltage reading.
WTLeft27 WTRight27
I trimmed each blade to 7” and tried another test of the voltage. I tested again and the voltage went up slightly, the batteries were set on the base to hold it down better.

WTMiddle28

I trimmed the blades again down to 6” long this time and the reading went up further. Kid Wind website explained that this is common as the blades have too much drag and smaller blades spin faster.

 

Pictures from Fuel My Brain Model Wind Turbine Workshop
 WTLeft29 WTRight29
Younger students will probably need some help with this project, older students should be able to build with minimum help.
Some small motors come with mounting bracket so the motor can be mounted easily to a flat piece of wood. For this class, thin foam that bends was used for the blades.
WTLeft30 WTRight30
The blades are spinning rather fast in front of the fan. For this hub, plastic tubing was used and a wood plug was used at one end
drilled to fit the motor shaft with a tight fit.

 


High Tech Kids Wind Turbine Competition – http://www.hightechkids.org/programs/mn-renewable-energy-challenge-4-12-grade

MN Renewable Energy Challenge (4-12 grade)

 High Tech Kids, in partnership with Kid Wind of St. Paul is again offering the MN Renewable Energy Challenge!!

High Tech Kids: The Minnesota nonprofit that coordinates team registration, resources, volunteer recruitment and administers the challenge. Established since 1999 we have served more than 22,000 students.”

Video explantion of the insides of a large wind turbine http://youtu.be/UakeTEJlXGw

Pictures from MN Renewable Energy Challenge May 5, 2012 ( I was a judge)

WTChallenge

Below: First group that I worked with to build this model wind turbine design, the students did well with this project. Project went well for the next group too.

WTCFK

13 thoughts on “Model Wind Turbine

  1. I had someone help with the banner on top and the basic setup and I have done the rest. Some of it needs to be adjusted for the newest browsers.

  2. Неy jսst wanted to give you a ԛuick heads up. The words in үour article seem
    tօ be running off the screen in Opeгa. I’m nοt
    sure if this is a format issue or something to do with web bгowser ϲompatibility but I figured Ι’d
    post to let yoս know. The style and design look great thoսgh!
    Hope yoou get thе problem reѕolved ѕoon. Kudos

  3. I keep trying to adjust this website to work with multiple browsers but it seems to be a losing battle. The width is very narrow. Opera is not one that I have available.

    Bill Kuhl

Leave a Reply

Your email address will not be published.