Airfoils

There are 3 types of Drag at work during flight - Profile, Induced & Parasite. In aircraft flight it is a delicate balance of lift and drag, in boomerang flight it is a matter of creating the amount of drag desired.

As the speed of an aircraft is increased due to more powerful engines and other technological advances - that angle as well as the airfoil are changed to produce a more neutral (lower) lift coefficient. This lower coefficient makes the aircraft more stable and easier to fly. Aircraft airfoils 

Traditional		A less pronounced leading edge and a rounder underside tends to produce a more neutral lift.
For lower speed aircraft. This airfoil produces the most lift at the lowest speeds.		Subsonic ..........................Supersonic
		Stealth - very unstable

Boomerang Airfoils - the Basics

Boomerang airfoils can be any of the airfoils found on aircraft. They can also be radically different to produce various flights.

Boomerangs can be modified by drilling holes in their wings, placing tape spoilers on the top or the bottom, or tape trailers behind the wing, or rubber bands wrapped around the wing to create drag over the top and along the bottom. Some people use weather stripping to create a spoiler on the top of a wing, or just a coin to create a raised area.

Taping weights to boomerangs is a very effective way to increase the distance as well adjust certain aspects of the flight, such as the trajectory or hover time and flight path.

Because of the different shapes of boomerangs and the wide ranging density of woods (even from the same mill and the same specifications) there are no hard fast rules governing the flights of boomerangs.
 

Undercut produces more spin and makes for a more stable and more accurate flight.

Traditional boomerang airfoil

A lower flight path can be produced by building the boomerang with a very laid back leading edge (subsonic or supersonic airfoil) or by using any of a number of drag creating methods.

The top choices of throwers to control the flight; whether for wind, distance, or trajectory, are weights in various positions and/or holes, tape are other materials attached to the wing to create drag.

Tape Spoilers

creates drag to keep the flight low and reduce the speed of the spin. A spoiler near the leading edge creates more drag than near the trailing edge. For short distance boomerangs like a Competition Fast Catch the spoiler near the front keeps the flight lower than a spoiler at the back. Spoilers are also a very effective way to fight a strong wind.

Holes

create turbulence and tremendous amounts of drag. They force the flight to stay low and fight strong winds. They can be various sizes. The closer to the tip, the greater effect they have.

Concaves carved into the underside of the wing also create turbulence and help keep the flight low. The Colorado Boomerangs Condor Comp has a very special concave cut into the underside. These concaves keep the flight low throughout the flight and really help put the brakes on as it is coming in.

Because of the different shapes of boomerangs and the wide ranging density and thicknesses of woods (even from the same mill and the same specifications) there are no hard fast rules governing the flights of boomerangs. Field testing and experimentation is the only way to truly determine flights.