Hi guys, I was reading an unclassified MoD document pertaining to glowing helicopter blades in dusty environments, particularly during take off/landing. Have any of you personally observed the phenomenon? Do you guys have any pictures of it? I'm particularly interested to know if it also affects the tail rotor and other rotors, like turboprops. Do you have any anecdotes of at what RPM you observed HRBS to occur, and on which helicopters (actually I just need the rotor diameters to calculate the tip velocities it starts at)? Some dumb questions but when the phenomenon occurs, does the air smell any different? Do you find you discharge static electricity on objects more readily when in the rotor downwash? I'm designing a laboratory test rig to replicate HRBS in a convenient setting and wanted to know if I need to be aiming all the way for sonic blade tip velocities, or can start seeing the phenomenon at say 100m/s. Yeah I've tried asking the contact in the document but haven't gotten a response yet.