This is the machine that will be going to the wind tunnel. It's been a real "stinker" and hasn't performed as well as the original or the 2x3. The only thing that is different is the way I made the trailing edge. I was thinking the open edge may be creating some drag and decided to clean it up. The aluminum is folded and pressed into the stringer and sealed in the front of the stringer. I'm now thinking the dirty edge of the others is working as a "flap" to some extent.
This also changed the wing angle that it seems to perform the best. I plan to run it in 5 mph increments from 10 to 30 mph and take output readings from this. As well, I want to change wing angles from 0 deg to 20 deg in increments of 5 at a wind speed of 15 mph and record output. Below shows the alternator its mounted on...
<BR<p>
This morning I took the mounting plate to the test facility to make sure that it would fit their bolt pattern and to find the size of bolts required to mount it. They had the small machine running ( open-loop ). Had the opportunity to walk around the machine and see its components in operation. They were testing the pressure in front and behind a round cylinder. I'm not sure what wind speed they were testing but it sounded like it was darn near max of the machine ( about 170 mph ).
It will be about 2 more weeks before I can get mine in to play with, they had the larger tunnel calibrated for testing different wing shapes at high speeds...
I've decided I have to own one ( at least a homebuilt unit that I can afford ). After having the opportunity to get a close up look at how they operate, as well as many hours this week reading documents on wind tunnel design, I think I can make one with a reasonable amount of accuracy ( far superior to what I now have ). I'm not concerned with winds over 30 mph, this should reduce the power requirement considerably.
I have 5 - 30 inch barn fans available ( have to take them out of the barn ) or a 64 inch ground adjustable propellor. The prop will handle 65 hp and produce a thrust of over 600 lbs but I think I can make the 30 mph wind with a 2hp 130V dc motor that I've been saving for the right project along with the speed controller. Sounds like a fun project... just need some lumber and honey comb plastic !
Just what I need... another project !
.