Patent ID: 8608598

Claim:
A boomerang comprising: a center part comprising at least one opening for attaching to a launcher, a plurality of blades extending radially from the center part, the inner ends of the blades coupled to the center part, wherein the blades are evenly distributed about the center part and wherein the blades comprise a front edge and a rear edge, the front edge describing a leading portion of the blades when the boomerang is in a rotational motion and the rear edge describing a trailing portion of the blades when the boomerang is in the rotational motion; and a ring, wherein the inner perimeter of the ring is mounted on the outer ends of the blades; wherein the inner ends of the blades comprise a first groove on the rear edge of the blades and the outer ends of the blades comprise a second groove on the rear edge of the blades, the first groove spaced apart from the second groove along the rear edge of the blades, the first groove and the second groove each join the rear edge through curved zones of transition; wherein the inner ends of the blades comprise a third groove on the front edge of the blades and the outer ends of the blades comprise a fourth groove on the front edge of the blades, the third groove spaced apart from the fourth groove along the front edge of the blades, the third groove and fourth groove each join the front edge at an intersection point; wherein the ratio between a distance between the first groove and the third groove, and a width of the blade is from about 1/7 to 6/7; wherein the ratio between the total area of the blades and the area of a circle defined by the ring is from about 12.5% to about 38%; and wherein each blade of the plurality of blades has a curved profile, wherein the curved profile includes a curve radius r 0 , wherein the curve radius r 0 is a first value when the boomerang is stationary and a second value when the boomerang is rotating, the first value is greater than the second value.