Ornithopter design
An ornithopter is an airplane that uses it's wings for both lift an propulsion. Some ornithopters have two sets of wings; one for lift and one for thrust and some lift. There are many types of ornithopter; from small rubber powered ones to some that are man-powered. For a grade 12 project which was around 15% of the total course mark, I decided to build an inexpensive one from scratch. I decided to make a free flying model with a compressed air engine because of the higher possible range compared to using rubber bands.
I bought an Air Hogs Ornithopter to use its air-powered single piston engine. I also kept the tank which was very aerodynamic compared to a pop bottle. I could have changed it to a pop bottle because the tank is actually connected to the motor by using a black cap with the same dimensions as a pop bottle cap for a longer range. But when I thought about it, using a 2 liter pop bottle was going to make the frame holding the bottle and the wings even heavier and harder to build (shown in the fuselage-wing joint picture) and also less aerodynamic. So instead of trying to get more range out the ornithopter I used the tank that came with the original ornithopter.
The materials I used to make it were balsa wood, epoxy, some paper clips, two one cent coins (I explain why in the paper "Grade 12 ILU" below), some transparent film similar to Mylar, and the tank and engine form the Air Hogs kit. Some pictures of the construction details are shown below:
Related papers:
Grade 12 ILU (Independent Learning Unit) proposal
NOTE: The following paper describes a basic model of how an ornithopter with a flat wing flies. Wing deformation, camber or realistic fluid flow are not included in the model. Check other sources to corroborate the information in this paper.