Manuel Schütz just released a new article on balanced boomerangs, how to design them and the importance of a well balanced boomerangs, including the elbow.
Abstract:
Dabbes Klaus H. Dabelstein introduced these kinds of boomerangs in 1987. He considered the classical shape with an annulus sector as elbow. The blade lengths are chosen such that the center of mass of the entire boomerang coincides with the annulus sector center. I widen the balanced boomerang shapes by two more possibilities: The omega and the non symmetrical multi bladed boomerang. I consider more realistic semistadium shaped blades instead of rectangular ones. These balanced shapes may be useful for analytic lift- and drag calculations as these boomerang types can all be seen as a combination of a ying ring and blades. The latter helps to understand how boomerangs can be trimmed. Additionally these shapes have a special appearance during the flight.
Resources
Very useful widgets created by Manuel to design different types of boomerang geometries.