It probably isn't very obvious how I can see. I cut about 10 holes in the curtain, around eye level. When the tornado is still, I can see with tunnel vision through one or more of these holes.
When the tornado is spinning, I get a 10 frames per second rotoscope view of the world.
I had a problem. The tornado would turn slowly, but the cloth funnel wouldn't build inertia and wouldn't speed up.
I had too much resistance, and my drive shaft was dodgy and slipping.
I attempted to make the crank drive easier. I removed some of the cowling I had been using to constrain the crank drivetrain. I also added screws, making it impossible for the springs to slide over the dowel instead of turning it, even at very high torque.
To lower friction, I cut a few inches from the bottom of the tornado cone.
The black cloth had been very close to my legs, and inevitably curled into it, slowing the rotation of the cone. By removing a few inches, I hoped to give myself a little more space, lessening the frequency of tornado-leg collisions.
I also bent and added a PVC ring at the bottom of the cone, so that even if my legs did touch, the contact wouldn't slow the tornado as much.
It looked great! This ring was about 18" around, and kept the bottom of the funnel nice and round. I used zip ties, and later hot glue, to keep it in place at the bottom margin of the cone.
On my next test spin, this ring seemed to help. I had eliminated some of the drag, but my dowel & spring crank wasn't able to handle this lower amount of torque either. The top spring would twist out of its position, unable to coax the giant conic curtain into orbit.
My next move was to upgrade the crank to a solid-steel solution.
I went to Harbor Freight tools, an oasis for tools I only planned to need one time. There they sold "universal sockets", a bending connection which are the real-world mechanic's solution to the "turn at an angle" proposition.
They also sold extraordinarily long socket extensions. With six pieces, I could snap together a completely new crank, free of springs and engineering question marks. The downside? This upgrade was $60 more than my wood-and-spring option.
There were only 6 days until the costume contest, and my entry was more like a barber pole than a tornado.
I bought the socket extensions. Let's build a heavy-duty tornado crank!
It was quick work to pull out the dowel crank and piece together a stainless-steel version.
The socket drivers are designed to be connected and disconnected. The only connection which had to be fudged was the connection from a 3/8ths inch drive to a 3/4" pvc pipe. I glued a 5/8" dowel inside a 3/4" piece of PVC pipe, then drilled and sunk a lag screw into it.
This slug fit snugly into the larger PVC pipe which drives the propeller at the top of the tornado. I screwed it into place. To push the bolt, I used a single 3/8" socket. The peices were snug. I gave them a wrap of duct tape just in case.
I can hear engineers cringing from clear over the internet. This is like driving a ceramic mug with an impact hammer.
The socket and driver solution didn't leave any spring action in the connection. This tornado had direct steering.
Did it work?
It worked! It looked really amazing in action. Whizzing around like no costume I've ever seen before. If this were an off-Broadway production of Wicked, I'd be the star of the show!
But I was going against some tough competition for a $5,000 prize.
Could this spinning cloud claim the prize against Robots in Disguise? Saturday night I'll find out. I'm going to the Exotic Halloween Ball.page 1 | page 2 | page 3 | page 4 | page 5 | page 6 | page 7