It was the AR Parrot drone that first piqued my interest in quadrotors early last year. I then started seeing autonomous quadrotors being made by universities and decided to make my own.
Soon afterward, I found videos of a multirotor variant people had dubbed the “tricopter” due to its use of only three rotors arranged in a triangular formation. Unlike a quadrotor, the net torque generated by the three rotors is not zero, so the tail rotor is mounted on a servo-actuated axle to compensate for this torque and provide yaw control.
Besides the fact that having three rotors and arms is cheaper than having four (a servo costs about $10), a tricopter just looks cooler than a quadrotor. That, and all the universities have quadrotors already. I want something different.
I found a gigantic tricopter thread on RCGroups that is a good source of other people’s tricopter builds, even though they all use simple radio equipment with no room for programming. The thread is actually useless to me past the first 100 posts or so. I just like watching their videos and wonder why they don’t fly any higher than a few hundred feet.
The material cost for the tricopter itself ends up being about $400. For this prototype, anyway. I will rebuild it with much nicer materials (aluminum? carbon fiber?) once I get past the testing/breaking stage.