Introduction: From ALDI to P38 Tricopter
ALDI is a small foam glider plane mostly made in mainland and is very cheap, I brought 3 less than 2 dollars in your money. I studied if I can combined two sets may very look alike the P38 lightning (as I thought). This instructable described how I combined two foam gliders to build a tricopter look alike P38 lightning.
But why tricopter? I've done several quadcopters, I found difficulty to idenfify the head and tail in quadcopter espeicially when it flown far away (not using FPV), so I wanted to maintain the traditional looking in aeroplane with head and tail, not an UFO, the second reason is to save one motor, to save power and water (theoretically truth), and the third is that I don't have a large open space to fly with, just as small as a basket ball field, and cannot flown fast, actually I like slow flyer even I can walk to follow with.
Step 1: Buliding the Frame
Actually the ALDI foam glider doesn't constitute the framework of this copter, the only frame is made by several pieces of plywood, the motors and ESC are moved from the quadcopter. Firstly I cut the head from the leading edge of the main wing, shortened the main wing to leave room for the fight controller in the middle, joint two stabs together, and mount only one head in the front.
The foam can be easily stick to wood by using heat glue gun, but it rather difficult to remove or change after glued , so think twice before try. I added two small rubber tyres to make it look alike and pretended it can runway takeoff (actually it can).
Step 2: The Tail Rotor
The L/R front rotor is straight forward, but the tail rotor is a little bit complex because the rotor needs to move left and right by a servo. I used a motor bracket which has two slots, one is 5mm width and other is 10mm, I put a 5mm rod in the slot and mount the rod in wooden frame tail, the servo disk also has a 5mm crank shaft mounted and inserted into the slot, and mount the servo underside to complete the tail rotor movement.
Step 3: Flight Controller
I used KK 2.1.X, there is nothing to change when using the default tricopter setup, at first I was worried the tail rotor will be corrected to move left right, because I used crank shaft which indirectly coupled the servo movement,
The KK told to use right turn prop in tail rotor, but I have no problem to use left turn prop, of course need to change motor turn direction.
The major concern in this copter is no protective measure on the front rotors, of course most drones hadn't, but to play safe, my next instructable will protect all rotors.