So I wondered if a boomerang type off-balanced weight might be adapted somehow to a gravity fed wheel?
"Some German scientists, seeking to discover the secret of the boomerang's curious flight, caused a party of Australian natives to give an exhibition of boomerang throwing at Munster.
The instruments used were of two sizes, the larger being a slender crescent about two feet long, two and a quarter inches wide, and a quarter of an inch thick, made of an extraordinary heavy Australian iron work.
This boomerang was jerked up into the air about 100 yards, when it flew straight away, then turned to the left and returned in a curved line back to the thrower, whirling around constantly and whizzing unpleasantly.
One badly directed projectile fell through a spectator's hat with a cut as clean as that of a razor.
A manufacturer, who has made some 11,000 toy boomerangs, believes that the mystery of shape lies in the sharper curvature in the middle, with unequal length of the two arms, which must be made of equal weight by unequal thickness.
The peculiarity of motion is due to the difference in the length of the arms, which diverges the curve of rotation from the circular."
"The short end of the boomerang stands up about 1 inch when the long end is lying flat on the table.
The length of the arms is in a ratio of 4:5. However, the long arm has to be exactly as heavy as the short one, so it must be somewhat thinner. The bend near the middle forms an angle of about 140 degrees.
It is especially important that the fibers of the wood have the same angle as the bend. If you saw or carve the boomerang out of a piece of wood in which the grain is perfectly straight, it will break when it hits.
Probably the most essential part of construction is giving the boomerang an angle to the wind. When the long arm is lying flat on the table, the short end should stand about 1 inch away from the table top."