Feel like Superman: Fly Underwater!

This instructable is extremely simple, but exceedingly fun.  Every time I tell people about this they look at me like I'm stupid, but after they try it one time they are hooked.  All you are doing is dragging someone underwater by a rope behind a team of runners.

I'll do my best to describe why this is so much fun in the theory section, but here is a short list of reasons why you should try this:
-the forces you feel are similar to if you were being towed behind a commercial jet...minus the effects of the freezing cold and thin air.
-even children can effortlessly cover distances underwater they would have never thought possible
-anyone can easily go faster underwater than an Olympic swimmer could go on top of the water
-check out the video!

Step 1 Theory

Most people have heard of a wind tunnel before, but few people have heard of a water tunnel.  The purpose of either a wind or a water tunnel is to test various aerodynamic and geometric parameters on a small scale model before the time and expense it put into developing a full scale prototype.  Wind tunnels are difficult to use when testing a model that is much smaller than the intended prototype or when the speed your trying to simulate is much faster than your modeling conditions can generate.  It is under these conditions that water tunnels can be used instead of wind tunnels.

By using the pictured set of equations through a process known as Similitude, you can equate all the forces a model would experience during a test to the ones experienced by the real deal.  So in this case, we can reasonably say that the forces you experience going a modest 7 mph under water are the same as if you were flying hundreds of miles per hour over the empire state building, just like Superman!
I originally intended to do the math and come up with an estimate of an exact speed, but it quickly became far to complicated to explain in reasonable detail here.  A quick comparison of Reynolds numbers (the second equation down) said that 7mph underwater would have to be equal to faster than 2000 mph in air; this isn't the whole picture though and can't be right as 2000mph is hypersonic, haha.

Comments

[NateGreatness]

LOVED IT!!! Read it and went out into my apartment pool to try it. Didnt have a bar so we just tied a loop in the rope. Looked dumb but never felt that kind of force before though. Helps if you have your hot roomate try it first though. I looked like an orca going through the pool.

[mmv5004]

Thanks NateGreatness, I'm glad you actually gave it a shot, and that it didn't disappoint!