Here's a couple things I have learned about these motor mills.
The motor should have vent holes drilled into the bottom of the case. I tried to seal up a brushed motor and some Zubbly conversions. After about a month I opened them up and they had rust on everything that would oxidize. My recommendation is to disassemble it, tape up the commutator and spray everything with clear enamel. Drill a couple 1/8" weep holes in the very bottom to let it breathe. One near the front and back.
The good part with using the PVC blades (like you have already found) is they are easy to modify and if you go overboard with the changes just trash them and start over. I've been through about 6 different configurations with my plastic sets so far and still experimenting. The fastest set I cut was only about 1" across at the tips and they were screamin' demons in high winds. The root angle will cause a lot of drag also and can self regulate the speed. If you have a router put a round over bit in it and it makes a nice leading edge. You can then trim off a little at a time until you get it where you are pleased will the performance.
Fishbonz
That is good advice about drilling the holes and painting the inside. I will do so. Thats what I had done to my small mill.
You also convinced me to trim these blades down even more. It was quite windy today, and I realized that the blades never did fly out of control. There was still too much drag on those wide blades. So I took a chance and trimmed another inch all the way down to the tip. Now they are about 3" wide at the widest part , down to alittle less that 2" wide at the tip. The length is the same. They USE to be an inch wider all the way down the blade. The blade rotor still starts up in a very low breeze-- probably about 6-7 mph. (which is good)
One thing I was worriied about though, is the blades bent inward somewhat down the length. I hope they don't bend anymore. At the tips, it is difficult to see any angle now at all. They look straight up and down. Difficult to tell. I can see now how AWESOME fast WOODEN blades would be with 4 degrees at the tips.
This was a GREAT improvement!! It goes MUCH faster now, even in Lower winds! It is doing 1 to 3 amps even more consistently now. I love it. Early today, when the blades were much wider, It did upto 6 amps briefly in a pretty big turbulent wind gust. Thats when I knew it was being held back alot. The blades didn't even make any noise. The winds are not that strong right now-- but it is doing alot of 1-3 amps even at this disgustingly turbulant ground location. I can't wait 'till I get my mounting pole/pipe soon and put it higher. I am quite certain it will fly out of control in a big wind now. So I must put the furling system on it very soon. I expect I will at least see 8 amps now! We'll see. I am very happy with it so far. It is doing what I had hoped it would do. I just have to LIMIT the amps now.
-Thanks.[ Parent ]
If you are concerned with blade tips striking the tower, shim the front of the motor up that will give some clearance.
Just an idea others have used.
Cheers.
TomW
"Education consists mainly of what we have unlearned."--Mark Twain[ Parent ]
Wondering how far they'll bend before they break. G- [ Parent ]
I believe I can make these blades even more aerodynamic. The only thing I have done so far with the edges it sand the leading edge down a bit with my finish sander. I will sand it some more. I may, as suggested, sand down the trailing edge to. So far I have done nothing to the trailing edge. [ Parent ]
