Note: This project is due for an update. Although the design instructions below will work, sometimes the shaft gets stuck when you pull the string. I am re-designing the project so the shaft is held in the middle by bearings rather than rattling around loose. Check back, or e-mail me to find out what the status of the project is.
The instructions show how to make a helicopter, as well as the pull-string launcher to get it up to spinning speed. The copter is all wing with no dead weight, so it goes astonishingly high. It is made of a tongue depressor--twisted to give the right angle of attack--with cardboard airfoils glued onto the ends. Non-hardening clay in the tips keep the copter going with momentum.The launcher is a piece of PVC pipe, wood dowel, string and disk.
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Depending on how you adjust your helicopter, you can get it to go as high as tall trees and hang in the air a long time. You can even get it to act like a boomerang so it comes back to you.
They say that knowledge is power. With this project you can learn some aerodynamic theory, immediately apply it and witness spectacular flights as a result. Although middle school age kids can make the helicopters, it could also be a challenging project for college level aerospace engineers.
For the instructions for making the launcher, click here.
For instructions for making the actual helicopters, click here.
For some cool links about aerodynamics and flight, click here
I have not made this yet, but here is an extremely interesting web page about an indoor helicopter you can make. http://www.davidkitecam.com/helicopter.html I don't know much about David Williamson, but if you like this site you will like the rest of his site also.