A revelation

[Ron Garret]

When I was in high school (and dinosaurs walked the earth) a science
museum in my home town held a paper airplane contest. One of the events
was a duration aloft contest, which was conducted by launching the
planes off of a second-floor balcony that overlooked the museum's atrium.

One day while pondering the contest I happened to drop a check. Instead
of just falling to the floor, it started spinning along its long axis
and flew quite a distance, and, more to the point, stayed aloft quite a
while. I decided to use this serendipitous discovery as the basis of my
entry in the paper airplane contest. I cut out a simple check-sized
rectangle of notebook paper, put a little S-shaped camber into it so
that it would tend to start and keep spinning, and just dropped it off
the balcony.

I won, and not just by a little bit. My entry completely obliterated
the more traditionally designed competition. (If memory serves, mine
stayed aloft about thirty seconds, versus about ten for the second place
entry.)

Of course, everyone thought I was cheating, so the next year they
changed the rules to say that entries "must conform to recognized
aerodynamic principles." That, of course, led to a big argument over
what that meant exactly. That year my strip of notebook paper took
second place. The "winning" entry (I put it in quotes because it was
actually disqualified on the basis of the new rule) was a little
cross-shaped scrap of rice paper about the size of a quarter. It pretty
much just floated away on a thermal and never landed at all. :-)

So they changed the rules again, and this time they got very clever: all
entries in the time-aloft contest had to carry a penny as a payload. So
I built a large (two-foot wingspan) version of my spinning check out of
computer punch cards (I told you this was back in the Jurassic) taped
together. I wrote "Piloted by Abe Lincoln" next to the penny, and won
another commanding victory. But there was still a lot of grumbling and
complaining that my entry was somehow "cheating", and I was not entirely
convinced that I wasn't. (That was my senior year, and I have no idea
what they did after that. Probably just breathed a big sigh of relief
that I was gone.)

Now, years later, I ran across this:

http://www.av8n.com/how/htm/airfoils.html#sec-spinners

Finally I understand why the thing flew! It really was flying! Thanks,
John Denker!

BTW, Denker's book is for my money the finest introductory text about
flying ever written, bar none. It is extraordinary that he has made it
freely available on the Internet. It should be required reading for all
pilots IMHO.

rg

[Larry Dighera]

On Tue, 28 Dec 2004 08:53:20 -0800, Ron Garret >
wrote in >::

>it started spinning along its long axis
>and flew quite a distance, and, more to the point, stayed aloft quite a
>while.

Many thanks for a provocative subject and a well told story.

I can recall (from my youth, probably Precambrian by comparison)
vendors selling "kites" on the southern California coast that operated
on this principle. As I recall, they were about 24" long with vanes
about 3" wide and had endplate disks that extended beyond the vanes.
There was a tube through the long axis, and a string bridle connected
to the ends of a rod that ran through the tube. I seem to recall them
as being reflective. The vendor would set up shop with a dozen or so
flying.