school glider project

My child is working on a glider project for her science class. Designing airfoils that will print and connect together are beyond the ability expectations. There is a lot of further design and tuning needed.

BOM:

1. M3x10 screws 6
2. poster paper
3. 5/16 wooden dowel, (any dowel 8mm and under should work with the set screw)
4. Sling shot if you want extra speed

Printing instruction:

A good first layer is vital, the wings have very little contact with the bed. They need to be printed with the leading edge pointed up to give the best strength and dimensional accuracy for the paper slot. I added a brim to hold it down, as well as turned off the skirt to be able to use absolutely all of build plate. supports should not be needed.

The leading edge of the wings are printed, as well as the wing mounts and nose. This gives the students a lot to experiment with. 

1. Wingspan is set by the size of your printer or what you choose. Chord length, wing area, and shape are customizable with the poster paper. (discussed later)
2. Weight distribution is customizable with the large/small nose cone, and adjusting the wing location along the fuselage. 
3. Horizontal and vertical stabilizers are about ⅓ the wingspan, but you can choose a different set to print. The area and shape are also made with paper and are customizable.
4. The length of the dowel can also be changed. My kid settled on a 400mm dowel, but tried the 300 and 500 as well.

The wings are printed with a .5mm slot in them to hold the paper wing material. The 5mm tall leading edge is a triangle to make printing at taller layer heights smoother and easier. The paper wing is moved 1mm up from the bottom of the leading edge to facilitate printing, two parameters with a .4mm nozzle. The 3.5mm on top gives enough of an airfoil to create lift with a reasonable amount of drag.

The main wing mount has place to hold the airplane while launching, or to use a slingshot.

Two screw go through the wings, which are stepped to keep everything lined up, then secured with two M3x10 screws. The screw holes in mount are designed to self tap in, a bit of force will get even regular machine screws in.

The screw is a set screw to hold it in position. I set it up to use an M3x10 with some sticking out, an M3x8 would likely be better if you have some. If you over tighten it may split the wood dowel.

The main wings have a 5deg dihedral angle to help keep the plane going straight.

The tail is assembled in a similar way, but with the vertical stabilizer on top.

Everything is designed to be as light as possible, and the wings tend to snap if the plane lands on a wing. Make sure the two wings are identical to help reduce this risk.