Why not consider this flying prototype funded by the US Army.....it shows much merit....and looks more sensible than with the HTR or V-22.
At 7:40 AM on June 17, 2005, while flight-testing for a U.S. Army contract out of Olney Airport in Texas, the CarterCopter reached μ-1 (Mu-1). This is the first time in history that any rotorcraft has reached μ-1. The condition was achieved during normal flight-testing while collecting data on a newly developed speed controller for the rotor. The milestone attempt was not planned but evolved as flight-testing proved the rotor to be very stable as the rpm was decreased. Test pilot, Larry Neal, was decreasing rotor rpm in small increments when he neared μ-1. With all systems stable the decision was made to proceed to μ-1. Data from the flight shows that the airspeed was 170 mph and the rotor was slowed to 107 rpm giving a μ value of 1. Previously, the lowest rotor speed achieved was 115 rpm. The μ-1 flight time was just 1.5 seconds before Neal reduced the throttle to slow the aircraft, but the aircraft was operated continuously above μ 0.9 for over 20 seconds, and the high μ flight was accomplished without incident. The pilots commented that the aircraft was so smooth that there was no vibration or noise to indicate that they were in a rotary wing aircraft, let alone one flying at 170 mph with the rotor slowed to 107 rpm.
CarterCopter Technology Demonstrator on CarterAviationTechnologies.com