Expert: Mark Janus Date: 2/10/2004 Subject: Paper Airplane science fair project
Question Hi Mark,
I realize this isn't an extremely technical question, but I need some assistance helping my 6 year old son develope his science fair project.
Matthew spends his days building paper airplanes and wants to do a project to find the best paper airplane. He understands that "Best" isn't a very good word and has decided that what he would like to find is which fold will yeild an airplane that flies the farthest.
We are using the scientific method for the project and one of my questions is how do we control the launch of the planes so that the only variable is the fold? Do you have any ideas of how a 6 year old could construct a simple launch mechanism for paper airplanes (he is quite talented at legos if that would help).
My other question is this - What is it in the structure of a paper airplane that makes it fly further? Is it the size of the wings? The ability of the plane to keep a straight flight path? The shape of the nose? I would use this information to help him come up with modifications on his folding and test the results.
I would be grateful for any help you could give us.
Sincerely, Joan Nitschke
Answer I would suggest using some form of flat surface (like a piece of cardboard) as a launching deck and a rubber band to provide the thrust. I'd use a rubber band for consistency... also you need a method to control the inclination of the launching deck (that angle should be consistent throughout your tests as should be the launch height)....
As for what makes a paper airplane fly farther, you hit upon many of the parameters... (size of the wings you mentioned would be called wing loading...wing size relative to the weight of airplane), the stability and trim of the airplane.... that is whether the plane flies straight or not, and whether it is trimmed for steady level (actually gliding) flight... as you will notice some paper airplanes climb, then stall, begin to fall, then climb again, stall, repeatedly.. those planes are not trimmed correctly... in other words the air that lifts the plane also can cause the nose of the plane to pitch up or pitch down...(on a real airplane the horizontal tail controls this pitching) but on a paper airplane the "tail" is fixed in one position....(thus there should be an ideal position for length of flight)
For example, you can take a single paper airplane by altering the trailing edge of the wings you can cause the plane to climb or nose dive ....
Where the center of gravity is also comes into play with regard to the "trim" of the airplane...
Also, if the wings are not folded (made) exactly the same then the plane will tend to fly to one side or the other (more lift is created on one side than the other)
I don't know if I helped much, but a seemingly simple thing like a paper airplane actually has quite a complex set of parameters which govern its behavior...
