animate : Balsa Glider
MEAM101 Final Project at UPenn
Fall 2012
For our final project for MEAM101: Introduction to Mechanical Design, we were given the wind up motor from an old-fashioned toy and two weeks to make something "awesome" that moved without wheels. My friends and I decided to go for something a little more challenging than the typical legged-walker: a balsa wood glider.
I had quite a bit of experience with model planes at that point, so I was able to make sure we could move quickly in the right direction. We used NASA’s FoilSim II to simulate different NACA airfoils and to choose one (2.08% camber, 10.69% thickness, 6° AOA, 0.8’ chord length, 5’ wingspan). The simulated properties of our wings drove the rest of the design. We constructed the wings and stabilizers from frames of balsa and carbon fiber, using a heat-shrink plastic called MonoKote to form the wing surface and strengthen the wings by pre-stressing the frame.
WING SKELETON
COVERING THE WING's LEADING EDGE WITH MONOKOTE
The wings attach to the fuselage (a single-piece hollow carbon shaft) with an adjustable hinge to vary the angle of incidence. I reworked the wind-up mechanism for increased speed and to interface with a small propeller, but it was difficult to start during launch and too weak to make a significant impact on the flights.
The final product had a five-foot-wingspan and weighed in at only ~300g. Despite the disappointing performance of the wind-up mechanism, we had many successful flights and the final product turned out beautifully.