Paper Airplane
A "Drop" Glider

I   
n the late 70's I worked in a factory at a stand up desk in the loading dock area. A paper fell to the ground and of course didn't land anywhere near my feet. This got me to wondering how far away a paper could land, in principle, from the person who dropped it.

More precisely, what is the maximum distance that a given paper can travel using gravity alone for power, and a shape to take advantage of aerodynamic considerations. These were my findings, some of which have universal validity for any paper airplane (or perhaps even real airplanes).

The paper size I used was ~ 7" x 5" bound as 'scratch' paper. I had a virtually unlimited supply so I adopted it as my standard.

Some rules:

  • No glue. No tape
  • No staples or paper clips
  • No cutting
  • Launch horizontally with just enough impetus to clear hand
(As I found out later, it is better not to use anything else anyway because these items add weight and restrict performance rather than enhance it.)
Here is a drawing of the finished product (about 3 weeks of development and testing).

I managed a 5 : 1 glide ratio under these stringent conditions.
I stood on a scale and held up my finished creation to a height of 8 feet. Released in the specified manner with a little twitch of the wrist. And . . . . . . . . got around 40 feet of glide in still air, much to the amazement of onlookers.

Each trial was accompanied by much fussing with the folds of the glider as each landing 'micro-disrupted' it. When slightly out of tune, the wings vibrated at about 10 cps through a distance of about 1/8", pivoting at the balance points on each half of the wing giving the appearance of 'flapping'. Actually, this was even more impressive than the most energy efficient flight.

Flight speed was about medium to fast walking speed.

This is a no stall glider, i.e. no matter how it is released, it cannot stall. If you drop it nose down it immediately (within a foot or two) goes smoothly into its normal glide path. If you throw it harder, it rises, slows, and goes smoothly into its glide. I could never get it to make dips to gain speed. It always smoothly went to its normal, straight, evenly paced glide.


The aspect ratio was about 4 : 1
Chord about 1.5 to 2 inches (can't remember exact figures because so long ago)
The vertical folds at edge of wing held the under wing folds in place and prevented much tip loss.

There was an active dihedral, i.e. the dihedral adapted to compensate for the inevitable roll you might expect from a near 0 dihedral wing. The fusilage folds were worked to make them fairly loose so that in effect this wing is actually two functionally separate wings that just happen to be going in the same direction. When one is about to roll out, the other compensates.

This was an entirely useless but enjoyable intellectual adventure that nobody else seems to be interested in. Even paper airplane enthusiasts don't take this 'purest' approach. They're always looking for longest distance or longest duration, never just drop the thing.


Google
 
Web ebtx.com


Ebtx Home Page