In "Certain" aircraft, ie some helicopters and a pre WW11 trainer [N.A. Havard] the blade tips go "supersonic" [The Havard has a very distinctive sound], and certain choppers also are encountering this problem. As far as I know, the Lynx has shaped rotor tips with weights to allieviate this effect.
The definition of "Trans-sonic" is the ability to fly supersonic [ie break the "sound barrier" in a dive], NOT in level flight
I hope that this helps
We aim to please, it keeps the cleaners happy
