# The Shape of Planes to Come

There’s a turf war in my brain about what shape the next duration world record plane will be. Part of my brain believes that Takuo Toda has it right, but I can’t help thinking Ken Blackburn’s rectangular design may prevail.

The rectangle should have better lift to drag. That elliptical lift pattern should be the correct solution for time aloft. The delta shape seems to hold the plane together better, with less throwing force lost to moving wings. Ken’s plane deforms a lot on the way up, while Toda’s hardly budges.

Notice the trade-offs? Almost all engineering problems are like this. Give a little to get a little, and try to figure out what the trade-offs really mean. With paper airplanes, you can figure there’s some element of idiosyncratic Reynold’s Number effects. We just don’t know what we don’t know about paper wings of this size.

I like to play in an open space like this, where there’s room to discover basic ideas with something as inexpensive as a paper airplane. We’re out on the fringes where no computer can reliably calculate the solutions. We have to go throw the planes.

It could turn out that Toda’s biggest contribution, aside from a superlative aircraft design, is the notion of optimizing paper size and weight. He’s traded A4 in for A5 and stepped down a paper thickness. That’s interesting. What’s the extra paper size get you, aside from extra weight? Lighter paper stock with bigger wings looks like a brilliant idea from where I sit. I doubt we’ll go back to a full A4 sheet again, and that’s interesting.

Will the next step be a rectangular plane from A5? Here’s where it gets tricky. To balance the CG and CL properly, a rectangular plane requires almost half the paper at the leading edge. So, is a rectangular shaped page the proper starting point? If that doesn't get you fired up to do some folding and flying, nothing will. Fold something new and give it a throw!