I teach a class called "Make and Throw a Boomerang in One Hour." Actually you make three boomerangs in this class:
1. A light weight indoor boomerang to learn the basics.
2. A heavy cardboard one that flies outdoors in a light wind
3. A boomerang made from heavy polystyrene foam that flies in light to moderate breezes.
All three use the same template. This instructable is for the indoor model.
Step 1: Template
1. Download this template
2. Cut it out
3. Trace around it onto a piece of cardboard. Cereal boxes work well as does the poster board.
Step 2: Start Cutting
Ready to cut
Step 3: Cut, Cut, Cut
The card board can bend a bit as you cut as long as you don't overdo it and put a heavy crease in it.
Step 4: Camber the Leading Edge
Boomerangs use aerodynamic lift (among other things) to help it fly and return. This is a "right handed" boomerang, pinch and bend along the "leading wing" as shown below.
Step 5: Camber Trailing Wing
Pinch and bend the trailing wing.
Step 6: Tuning
This part can be tricky but typically both wings need to be bent up just a little bit
Step 7: Throwing
Throwing is just like a real boomerang.
1. Do not throw at anybody. Yes this is cardboard but NOT practicing dangerous behavior can be a useful process.
2. D0 not throw it like a frisbee. It tends to make a rapid ascent and and even more rapid descent in most instances with little predictability. Again not super dangerous with cardboard but . . .
1. The grip is a light clasping between the thumb and knuckle/first joint of the index finger.
2. The throw is like snapping a whip. You don't need to "twist your wrist" to make it come back.
Youtube helps as always:
These youtube videos are for outdoor but very good: