The worlds arguably first true rigid rotor and the real life example of what happens to uncorrected flap back and in-flow roll is the Aust Aboriginal returning boomerang.
As the boomerang is thrown, the increasing airspeed coupled with the rotational velocity causes the advancing blade to flap back and make the boomerang to both climb - (resulting in a decreasing airspeed).
Simultaneously, the disymetry of lift on the advancing side of the disc causes the boomerang to turn toward the retreating blade side (inflow roll).
As the IAS decreases to zero at the boomerang's apex, it momentarily hovers until gravity takes over and potential energy of height is converted once again into airspeed as it dives toward the ground. Once again as IAS increases, the flap back/blowback pulls the boomerang out of its dive and miraculously levels it out with a slight climbing attitude as energy progressively is lost from the system.....now heading back toward where the thrower was standing originally.....
Some might say "white man magic" .....or is it simply a fantastic practical demonstration of aerodynamics at work and its effects on a true rigid rotor???....and perhaps the best practical demonstration flap back and in-flow roll (disymetry of lift)
