| T O P I C R E V I E W |
| tecon |
Posted - 25/03/2008 : 01:45:51
It was actually my 12 yo that named this 'Lil Dopey, it's not much to look at as it wasn't designed, merely scraps thrown together to attempt a wind generator. The motor is a Ametek 30v, the rotors are actually 2 of 3 "test blades" I purchased from WindStuffNow a couple years ago.
As terrible as it looks, and although 2 rotors will take more wind to get turning (14mph or so start up), it only has two speeds, stop and charging, there really is no in between.
Nice wind today here in the center of America 
Best,
Tim |
| 9 L A T E S T R E P L I E S (Newest First) |
| ghurd |
Posted - 28/03/2008 : 16:54:28
My white blades, a complete mini-gen with green blades, and maybe some magnets, came in the small flat rate box.
2 blades can go faster than 3, etc, but for power extraction the blade design needs to include the blade count.
I expect these are designed for 3 to 5 blades. They aren't quite to NASA specs!
Your "2 Speed" discription makes me thing you'd do better with 3 or 4. Bummer he's sold out.
Mass is not important. I flew smaller blades on a nearly cogless monster-size motor just fine.
The rotating parts weighed 8 or 10 pounds? It didn't react to guts very quickly, but there isn't much power in gusts anyway.
The problem is cogging and bearing drag.
G- |
| MattM |
Posted - 28/03/2008 : 01:10:28
Tim probably got those 35-40mph gusts we were seeing south of the big city.
I can't wait to see what the spring storms have in store for us this year! Should be exciting.
Go Huskers! |
| tecon |
Posted - 27/03/2008 : 18:14:09
ghurd,
Ed actually sent mine in just an envelope! and I've already broken #3 of the set, thus why only two flying.
2 rotors of course can achieve a greater rpm than 3, and 3 greater than 4 and so on, but I am not sure what the increase (percentage wise) needed in wind speed is though.
One would assume a reduction in mass (very generally speaking) 33.3%? (one rotor less) would require only 33.3% more wind speed, but I think the required wind speed to turn 2 versus 3 versus 4, etc. is much higher than 33.3%?
Tim
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| ghurd |
Posted - 27/03/2008 : 17:04:01
I couldn't believe the box Ed fit them into!
"Flying" mine on a 3-blade 3-ph 1/3HP induction conversion.
Meaning every so often I take it to a causeway, do some measuring, testing and tinkering.
It starts easy, and makes more power than I expected.
No way I had them going 850 RPM, but never had them up in that much wind either.
G- |
| tecon |
Posted - 27/03/2008 : 16:08:10
Ghurd,
They certainly do flex some, if you own some - then you know they are really thin and very cheaply made.
There is actually 2 hubs on this one, a smaller front hub in which the 2 blades are attached, and a larger back hub to support the blades.
It is really interesting messing with this setup, with only 2 rotors, as I stated, it will take a fair amount of wind to start them, from there it is truely a eye popping frenzy as the rpm's climb exceedingly fast. I did a spot check Monday and was seeing 28v open, which in turn is aprox. 850 rpm on the Ametek 30v's? I don't know the actual wind speed at the time, it was all over the board that day.
These little blades also retain very little if any energy, thus, when the wind gust subsides, they stop nearly on a dime.
Fun to play with for sure,
Tim |
| ghurd |
Posted - 27/03/2008 : 14:45:33
How much do they flex back in a good wind? I'm a bit afraid to leave mine flying.
Ben, it's about 32" diameter.
G- |
| gotwind |
Posted - 25/03/2008 : 21:23:45
Great start Tecon,
I notice a larger turbine in the background in the first picture, you probably know the added benefit of increasing the number of blades.
You can also go up to 4 ft diameter with the Ametek 30 in good wind.
Difficult to appreciate what diameter yours are from the picture.
Keep us posted, it's looking good so far.
Ben.
The Futures Green - Getwind of it. |
| tecon |
Posted - 25/03/2008 : 15:06:11
Sounds great Matt!, sent you a PM.
Tim |
| MattM |
Posted - 25/03/2008 : 02:57:44
It looks good, Tim.
pm me if you still want to get together some time. I can hook you up with some free blades, just have to let me know the lengths for which you're aiming. Would be sweet to see 5-10 blades on that little hub. :)
Go Huskers! |
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