The most common drone varient is a quadcopter with 4 motors, a tricopter uses three motors and a servo at the back to control rotation. I designed and flew my own tricopter as I was interested in electrical propulsion systems.
The original iterations had little adaptability and space for other electronics, however the final derivative comprised of a sleeker design and space for FPV equipment, as well as changes to accommodate an on-board camera. The flight time from a single 1500mah battery is roughly 15-20 minutes, depending upon flying style and payload.
The whole design was laser cut from 3mm plywood, with 10mm square aluminium booms to save weight and reduce cost. The propellers were upgraded to carbon fibre, to increase durability and reduce weight further.
Commodity components were used, including the motors and Electronic Speed Controllers (ESCs). The Flight Controller and ESCs were subsequently flashed with updated firmware to increase the stability of the tricopter whilst flying, by allowing for a higher sensor refresh rate.
The turning mechanism uses a high power servo to rotate the tail motor around a rotary joint, in order to angle the back motor. This type of turning system allows for a higher turning rate than that of traditional quad-copters.
The on-board camera allows for simultaneous HD (1080p) recording and live output for transmission to a user headset for First Person Viewing (FPV). Stabilisation of the camera system is achieved through two methods; balancing all motors and propellers to reduce vibrations prorogation throughout the frame and a separated camera platform, attached using vibration absorbing tubing.
The following images show the assembled tricopter, the concept render (using Blender's cycles render engine) and a more finalised version of the frame.