Expert: Mark Janus - 2/22/2009

Question
Mark, my nine year old son is doing a science fair project on paper airplanes. He is using different weighted paper and wants to know which weight of paper will fly the farthest. He is predicting that the light weight paper will fly the farthest? What is your expert opinion and why would a certain weight of paper make a difference in the distance the plane flys.

Answer
Hi MaLinda,
Well, that's an interesting project to work on with your son...  actually there are two issues here...  sometimes a contest is to see which plane flies the "longest" (in time)...  i.e. longest endurance and then there is what you've described....  farthest distance...  generally I would say that the lighter plane would stand a better chance of longest duration....  and the heavier plane the farthest distance....  all things equal (such as how the planes are launched, from what height, and the size and shape, etc)  the lighter plane should win....  but in a elementary project releasing the paper from the same launch mechanism (i.e. same speed and/or the same amount of initial thrust) is usually the biggest factor.... for example simply throwing a plane generally doesn't yield either of the above....   you should use some sort of rubberband launcher (this provides the same thrust force each launch) and launch from the same height each time.  The plane(s) should be as identical as possible (that's also hard to do), you should be able to get a decent idea of the function of weight relative to the distance flown...  Under those conditions, I would say the lighter plane will win

mj