I cranked up the tunnelles wind tunnel for the first time 2 days ago.
At first I used a small fullwave bridge rectifier in the power supply for the 2 hp dc drive moters. It made it to 10 mph but went up in smoke shortly there after.
The next day I made a fullwave bridge from two 70 amp battery isolaters and one 95 amp battery isolater. It works very well even up to 170 volts DC.
With the higher amperage diodes I was able to reach 28 MPH at 20 ft. from the blades.
This unit is in a covered area floor, wall on one side and ceeling.
Even though the wind was around 10 mph outside no detectable wind entered the tunnel area.
I mounted an anamomiter (spl?) 20 inches infront of the genny to be tested.
In this physical are theres enough room to test 4ft to 5 ft blades.
Next will be to set up battery bank near by.
Test equipment will be.
3 anamomiters, infered tack, amp meters, volt meters.
Watching the wind direction part of the anamomiter, the wind from this thing seems fairly straight and stable.
It sounds like a Sesna airplane when its going top speed.
I use a 5KW variac to control speed.
I hope to test severaltypes of 4 ft blades soon.
Hey DanB can you recamend a design on a 4 ft wood carved blade with constant angle, no twist.
I know you like this type of blade and you say there would be littel addvantage to a blade with twist in the large sizes but I think this test is scalable.
If theres just a diferance for these small blades I would like to find out how much?
I know there may be some turbulance here but for now I'll be test without wave guids to straitin out the air flow. At least all blades will be seeing the same wind conditions. It fun to be in control of the wind speeds for these tests.
Heres a picture again.

JK TAS Jerry