I’ve made a few over the years from plywood and shaped with a sander. They are flippin awesome, always come back to my feet and on occasions have managed 2 full revolutions.
Launching them out over a lake is particularly enjoyable, especially if you are with a doubter who doesn’t believe it will work.
Mine have generally been quite big, maybe 18-22 inches or so at least. You absolutely need to be completely away from anybody because if you hit them you will kill them. Always launch into a wind but off to the right of the wind direction (assuming it’s right handed and vice versa). The boomerang needs to be angled correctly – say 45 degrees to give lift and curve. Too flat it will climb and stall, too upright it will curve into the ground before it completes the loop. As you get better you can use the wind to do different things, but to start stick to light winds. Still conditions can be tricky so not always best to learn in as you will lack the breeze helping to push it back to you
Starting out, don’t practice over rocky or even hard or firm ground. If you stall you will crash hard and the boomerang will break in two.
Think about how the aerofoil will work as it rotates and shape accordingly