Third trailer is the charm

I remember at last years National KidWind Challenge watching the NREL folks unloading their wind tunnel from the semitrailer with the huge fork lift. I should have realized that there would be more to building a variable high speed wind tunnel than just getting a big fan. 

Moving the wind tunnel and getting 240 volt power to it would require considerable thought, time and effort. Here is trailer number three. A 6' by 12' aluminum beauty borrowed from one of my coffee buddies.

First item of business was to fill in the gaps on the ramp so the 3" wheels on the tunnel would not hang up.

Then to fasten a piece of thin band stock to the back side to hold the fillers in place when the ramp was folded up for travel.

Needed to figure out how to attach a winch to the front without drilling into the trailer. Lucky I had the bottom roller left over from trailer #2 to recycle.

And there we have it. Ready to crank and load?

I had learned of the problem with the straight wheels on the back end. These solved one problem when loading but created another steering when trying to move the fan around from place to place.

I would solve this problem by adding another caster wheel that could be raised or lowered. I could screw this caster wheel down for general movement on the floor when the other two were raised.

OK, time to load this puppy. Several orange plastic strips were placed to lessen the uneven steps between sections of the trailer.

This was going to be a full on loading test so the base and the test chamber had to be folded up and put on carts to be moved around.

All this was designed to be loadable by a single person. That way for sure two people could make short work of it.

Things are going pretty good so far. You can see the base against the fan and the test chamber ready to go.

OK the Variable High Speed wind tunnel is loaded!

Ready to give it the road test and see how it pulls at 55 mph. But what about a generator to run it?

Another coffee buddy to the rescue! There was room on the 12 foot trailer for his 7500 watt generator to ride.

Did anyone say 240 volts? Did not see this coming.

Not to worry. Just need a good ol' adapter. Right? Well there is a story to tell but lets just say I learned exactly what is means when it says 125/240 volt connection. I learned the hard way that what is shown here would not work.

This is the style plug I needed to power up the fan motor.

I got the plug I needed and wired it up after some considerable head scratching.

Now you would think that after all this it would work. So did I but what you are looking at was the new problem that I did not figure out until I was half way down the road to consult with Tuescher Electric what the problem might be. Luckily it dawned on me that I had not plugged in the fan motor to the control box. Idot!

Drilled a hole in the top of the test chamber to put the hot wire anemometer rather that having it on the side like before.

And here is the proof performance. At full motor speed (1750 rpm) 12 m/s. It should be noted that the motor on the fan can be "pushed" because of the short run cycle time we do for testing. This would increase the fan blade rpm up from 300 and that would increase the wind speed. Something the think about in the future.

I think we have got something here that will really "suck" in a good way and impact the future of the KidWind program.