Optimized 4 foot windmill rotor made from 4" Schedule 40 PVC pipe. For CCW rotation, root of blade 3/4" from the center of hub, TSR of 8 @ 5 degrees AOA, loaded RPM 375@6.7MPH(3M/S) 1232@22MPH(10M/S):

Cut a 23-1/4" length of 4" Schedule 40 PVC pipe lengthwise into 4 equal pieces.

Take one and lay the inside of the pipe down and oriented left (root) to right (tip).

On top-left hand corner drill a 1/4" hole 3/4" from the left (root) and top (trailing edge).

Drill another 1/4" hole 3/4" to the right of that hole.

Mark the right edge (tip) at 1-5/16" from the top (trailing edge).

3. " from the right (tip) mark it 1-7/16" from the top (trailing edge).
6. " from the right (tip) mark it 1-5/8" from the top (trailing edge).
9. " from the right (tip) mark it 1-13/16" from the top (trailing edge).
12. " from the right (tip) mark it 2-1/16" from the top (trailing edge).
15. " from the right (tip) mark it 2-7/16" from the top (trailing edge).
18. " from the right (tip) mark it 3-1/8" from the top (trailing edge).

"Connect the dots" with a smooth curve. Use a french curve if you have one.

Cut the bottom part off and discard.

Sharpen the top (trailing) edge on the inside only! Do not sharpen the 3" on the left (root).

I've made pvc blades out of the 6" pipe and it seems to me that 6" wide at the root is too much curve (excessive drag) hanging over.  I think that would be like 3" wide.  The blades I made were 3.25" at the widest point.  

The cogging of those motors can be a real pain I know. Small mills have to be able to start on a feather and this is difficult to do with 4 and 5 footer DC motor mills.  
I would try 5 thin  pvc blades (same 54" diam) myself.  It would give it  a lot more start-up power. (but it won't mean any more power though than 3 blades)

The other thing that can cause big start-up problems is balancing. I find It is impossible to balance the blades with the DC motor itself due to the cogging. I always just use a bronze bushing in wood separately, to balance the prop more accurately, or you can take the rotor out of the treadmill motor and hold on to the two ball bearings and balance it that way very well also.

I want to do the second set of blades right..I have to comment first on Roadrangers reply. When I got to the part in the instructions for making the blades, I followed this link and made them from  six inch pvc cut at 29.75 length and divided into two 150 degree pieces and one 60 degree piece..... http://www.thekevdog.com/projects/wind_generator/

My holes on the hub are 1" apart and 1 7/8 from the shaft center.

This Generator spins CLOCKWISE because I got negative voltage readings going Counterclockwise. Are the Instructions you gave me correct for the info I just revealed?? Can you also tell me how you arrived at the cut-in speed of 480rpm for my machine- I'm learning and am confused at all the reading I've done!

How many watts can I get out of this and is this motor feasible for this project?

I did not finish this by any means...Just set it on a stand to see if it spins before proceeding to the next level.

To CmeBrew---
The blades seem balanced fine..They do not stop at the same spot when spinning it manually.

I really appreciate the help-Just need a little bit more to keep going!

Question---Do you have the motor hooked up to anything? When testing, it is unhooked--- right?  Because it seems to me, with those VERY wide blades, at that very big angle, it would start up VERY easy.  It confuses me.  I suspect it will be very difficult to get the high speed you will need with those wide pvc blades hanging over that far near the root side.  
I would trim off 2" off the width and add a couple more blades myself.

Have you actually tried to test the mill in the wind outside? The REAL wind outside is probably better than box fans or blowers.

Perhaps you can make sure the motor is not semi-shorted out or something by hooking it up to a 12v battery directly and letting it spin.  It should turn with some fairly good force around 400 rpm.

You will be hard-pressed to get any charge under 10-11 mph due to the higher cut-in rpm.  300-350 rpm at cut-in would be much better.  I would get a much lighter hub and try the pvc blades at the 54" diameter you have.  If after the hub change, it starts alot better, then you might look into changing the blade design a little?  Pvc blades may not "turn-up" enough rpms to make it work for you.  A good 4.5 to 5 ft. dia. Fast wooden prop might? work out ok. Good luck!

If it were me and I had no other choice, I would do 5 pvc (or, wood blades would be somewhat faster) blades (6" pipe)  4.5' diameter (you may wish to trim them down later to get more rpm).

I would make the pvc blades 3" at the widest point, and 1.25" at the tip. (tip being 4 degree angle almost straight up and down)

And You might want to try a "Magnetic de-cogging mechanism" like I did on my treadmill motor mill here:

  http://www.fieldlines.com/story/2007/3/9/2533/99152

Your motor probably has 12 poles and thus 12 big cogs per revolution.  So you would need only 12 little magnets. (guess- 1/2" diam. by 1/8" thick ///and use big pan head wood screws or similar)
The objective with the 12 magnets spaced correctly is to make 24 smaller cogs per revolution instead of 12 big ones.

It is difficult to say, but if you understand the principle well, you might reduce the cogging anywhere from 20-50 percent.

Be very careful to get your alignment exact, or it could make the cogging even worse!
Mine worked quite well for a time, but during a 'hurricane wind' (probably 70mph gust) it screwed the hub on even tighter than I thought possible, and screwed up the alignment an eighth of an inch and worse cogging came back. (I never fixed it with a 'sheet metal washer' because I knew I was going to take it down in the spring and make a bigger mill)

I took that downwind mill down earlier this year since I didn't need it any longer since I have a 6 footer now.

(If anyone ever makes one of those downwind mills, be SURE to put a wood or plexyglass 'beard' mounted below and to the motor in order to help it turn (yaw) better in the lower winds!!)

I sorta like the heavy hub though.  It seems it helps to keep it turning in lower winds better and  keep it from stopping as much from the cogging.  Inotherwords, it seems it smooths over the cogging better in low winds and 'coasts' the prop better.

Wait for a 10-20mph wind day and see what it does.  4 footers don't do anything under 10mph.  My 6 footer only gets 'bits and pieces' of low wind on a typical 5-10mph day which amounts to almost nothing anyway. (maybe 10-50Watt hours??)