Paper Plane Launcher

Fun little paper plane launcher I built with my kids this weekend.

What you will need:
* Makeblock set
* 25mm DC engines (lowest gear ratio you have), 4mm axis. I am using Polulu, 12V HP 4.4:1 (https://www.pololu.com/product/3201)
* Battery (depends on engine, I use an 11.7V LiPo battery)
* Assorted screws
* Two of each of the printable parts
* Two O-rings (R-32, I/D 50.39 mm, O/D 57.46 mm, Section 3.53 mm)

I printed mine with both extruders at the same time to save time, and didn't have patience to switch out the color - that's why half the parts are black and half the parts are white.

Build notes:
* Print two of each part.
* Build the Makeblock structure as shown in the images.
* Mount the DC engines loosely in the motor brackets and the brackets on the structure.
* Put the O-rings on the wheels, and the wheels on the motors.
* Adjust the distance between the motors until the O-rings, at most (when turning them), very slightly touch.
* Remove one wheel and verify