Last Day of May

For post #4 I figure I should write something a little more substantial.

My son watches a ton of Mythbusters, which is not a bad thing all in all.  They build things, investigate things, and there is some actual science on the show.  All good.

But most episodes have at least one point where I'm practically screaming at the TV because they have apparently not done some basic research.  This is usually aligned with the myth, but that doesn't make sense to me.  If you are going to investigate the myth, you have to research the science that is being skewered (apparently) by the myth.

My latest outrage was the episode where a bush pilot in Alaska had his plane shredded by a bear, and he proceeded to fix it with duct tape.  I'm an aeronautical engineer by training (not career, alas), so this was right up my alley.

They made a big deal about the sides of the fuselage 'rippling' in the slipstream when they were flying their patched up plane.  This is a Piper Cub type of plane: a metal tube frame (NOT monocoque or rib and stringer where the skin takes stress).  A metal tube frame doesn't need any solid surface sides!  Look at planes from the 1910s that were frequently just tube frames with no skin.  So right there they could have provided some valuable science and shown that that type of plane will fly with no skin.

Then they went further, and stripped the entire skin from the plane (where did they find a donor for that!?  Or did they just buy the plane?).  They wanted to replace the entire skin with duct tape.  OK, no we are getting to some nitty gritty, as the rudder, vertical tail, wing surfaces and ailerons would need skins.  They started by weighing the removed skin (10 pounds) and starting with the equivalent weight of duct tape (about 5 rolls).  Those five rolls didn't go far enough, so they started adding rolls to get the entire plane covered.  But they made a big deal about the weight and balance of the plane getting all out of whack.  In the end they used something like 20 rolls (40 pounds) and got all up tight about whether the plane could still fly.  Seriously?  Maybe if you got a 350 pound test pilot to try it out or something, but most planes can carry a pilot, fuel and 40 pounds of stuff. (OK, an ultralight might have a closer margin, but not a bush plane).

Not surprisingly the plane flew just fine.  Fun episode, and myth confirmed, but missing some important science in my book.