Saturday, November 6, 2010

We Fly at iFly

   Joshua, our oldest grandson was born on Halloween. This year, for his tenth birthday, he wanted to go skydiving in a vertical wind tunnel.  There happens to be, within an hour from his home, a vertical wind tunnel. 
   Joshua’s mom and dad met at a drop zone where they both skydived. Dad was a skydiving instructor and mom ran the manifest where she kept the airplanes loaded with skydivers, and, when the paying customers were taken care of, went skydiving.
   Joshua’s dad arranged for all of us, grandadscience, grandmother math, and he and his family, to visit the iFly vertical wind tunnel near their home.
   The scientific principle used in the vertical wind tunnel is simple. Instead of a person falling through the air at 120 miles per hour, a big fan blows high-speed air upwards at and around a person.
   A ping-pong ball and your hair dryer will quickly demonstrate to you the feasibility of this method. Hold the hair dryer upright in one hand, turn it on to the highest setting, and drop the ping-pong ball it on the air stream. The ball, contained in the air stream, will float above the open end of the dryer. Watch this short, 20-second video to see how this works (with no one around to help me, I had to put the hair dryer in a stand so that I could take the video).
   The hair dryer video demonstrates two scientific principles; first, Bernoulli’s principle tells us that the pressure in an air stream is lower than the pressure outside of the stream. That’s what keeps the ping-pong ball centered. Second, the weight of the ball equals the force due to upward air flow. That keeps the ball suspended in the airflow.
   Watch this video to see Joshua take the place of the ping-pong ball in the iFly vertical wind tunnel. Towards the end of the video, his instructor takes him up to the top of the chamber.
   Well done Joshua! Now here’s Jordann, his sister, flying in the tunnel. 

  It was a great family outing and we are all excited to go again. In case you are curious, children as young as five, if genuinely eager to do so, are allowed to fly in the wind tunnel.
   As shown in the video, a qualified instructor is with you at all times. You may have noticed the instructor giving hand signals to the fliers. Two outspread fingers means drop your legs. Two curled fingers, lift your legs. Spread legs drive the flyer forwards and curled legs causes the flyer to back up. The basic tunnel flying skill is learning the correct leg and arm positions so as to stay centered in the airflow. Thumbs up means the body position of the flyer is correct.
   Joshua and Jordann, Here’s a Thumbs Up from mom and dad, grandadscience, and grandmother math!

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