Ghosts of Fool's Past

Well, we fell on our collective faces in our attempts at an April Fool's story. We just couldn't top our fake wind tunnel from 2007 (and we probably never will), so we're resurrecting it instead. We never intended this story to really fool anyone, we thought the photoshopping was just too fake. But fool it did. For additional comedic effect check out this forum thread, where some of the great brainiacs of cycling discuss the efficacy of our imaginary tunnel.

Ok, before the inevitable 'you're out of your mind' comments, let me explain myself first. I got a lot of feedback on my series of articles on my homemade wind drag test rig (Pt. 1, Pt. 2, Pt. 3), and some of it was printable! One reader, a fellow biketechreview geek from the midwest, wrote to tell me that he had an old windmill just laying around in pieces. He offered to send the blades to me for free, on the stipulaton that I build a full sized wind tunnel with it. I had no intention of taking my tests further, but this was just way too intriguing to pass up. I figured I'd sit on the blades while I researched the subject. I could spend a few months scouring ebay for spare parts as well. Schmalz offered to look into cheap warehouse space in Jersey, another reader suggested this design, and before you knew it, the NYVC wind tunnel project was born. The rotors arrived in far more pristine condition than I imagined possible. The hub had a solid axle and smooth running bearings. All I had to do to mount it was drill a 1/2" hole! The whole thing started to scare me. This was going to be a lot easier than I thought, and once I become obsessed with something I have to do it right away. I figured with three days in Schmalz's woodshop and two days for assembly, I could get the basic structure built.

As luck would have it, this was the week of my wife and kid's annual visit to grandma in Boston. We had no leads for a space in Jersey, but there was no way I could wait any longer. I spent three days last week cutting 2x4's and 3/8 plywood sheets in Schmalz's basement, and got the stuff home the afternoon Laurie and Sofie left for Boston. A couple of sleepless nights later the NYVCWT was done. (Behold, the power of insomnia!) It'll be dismantled Sunday night, and as long as my wife doesn't visit this site, she'll never be the wiser. So, you see, I didn't really WANT to build a crap wind tunnel in my apartment. It was thrust upon me. Really. Besides, there isn't a cat 5 in the city who hasn't been lactate tested, so why not build a wind tunnel? I predict the NYVCWT will be booked solid this time next year.

So how does it work? The tunnel itself is a pretty cool design. It pulls the air rather than pushing it. I'm hoping this means the airflow will be less of a vortex. Also, it has a large bell shaped inlet. The idea is that it draws a larger volume of air and gradually accelerates it by squeezing it into a smaller channel. Supposedly this smoothes out the airflow as well. A couple of cross braces at the outlet provide the fan mount. The build was pretty straightforward: a series of rings are hammered together out of 2x4's which are then joined by longitudinal ribs. Once the skeleton is done, it was simply a matter of lining it with 3/8" ply. I dropped some frosted plexiglass on top to provide light. Thanks to a meticulous drawing, the pieces came together without a hitch.

For now, the NYVCWT will strictly be for riders who can ride the aerobars on rollers, and can start and stop without handholds. It's tight in there. I'll eventually drill out the feet of my TruTrainer rollers and mount skateboard wheels on them. Rider and rollers will roll inside the tunnel, and I'll use the same pulley/weight system from my helmet drag rig to determine drag force. This has two advantages: I won't have to figure out how to work with strain gauges, and I won't have to get someone to write a program to plot the forces and average them. It may seem like a crude system, but it was good enough for the Wright brothers.

The fan will be belt driven by a motor. Schmalz wound a rope around the axle and pulled like mad, and the iBike registered a 16 mph gust! We'd have a picture of this, but I was riding inside the tunnel while he was doing this. He was able to generate such a strong gust because, I suspect, he wanted to blast me off the rollers. I must confess it was a bit scary in there. I'm not 100% confident riding aerobars on rollers, and I kept picturing a crash where I'd fall through the plywood. As you can see in the photo, we did the test facing the fan to maximize the Schmalz powered gust.

Time for Hate With an internal diameter of about 6 1/2 feet, there simply isn't enough volume for a proper wind tunnel. The presence of the rider has the same effect as pinching a garden hose: the air channel is reduced in size, and the air will be forced to accelerate. This will probably invalidate much of our results, but I'm hoping that the results will be consistently skewed one way or another. Maybe I'll book myself a visit to the SD LSWT. That way, I'll be able to compare my results from both tunnels, and hopefully establish a conversion figure for the NYVCWT. Other drawback of the NYVCWT? Big rotating sucking knives situated a mere 3 feet from your butt.

So where does that leave us? Well, we're still looking for space. Anyone have a big empty room we can borrow? Since I wrote the previous paragraphs, we've come into a marine engine. Schmalz assured me that he's a good mechanic and knew his way around an engine, so I let him fire it up inside. A cloud of smoke and two traumatized animals later I learned my lesson. Do not trust the Schmalz. So we're also looking for someone who knows motors. Stay tuned for NYVCWT Hate Part Deux.

Please disperse. Nothing to hump in here.