CarterCopter Technology Demonstrator
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.
The CarterCopter Technology Demonstrator was our first prototype. The historic µ-1 flight was the culmination of more than 12 years of research and development, during which time the aircraft underwent many developmental changes. We learned many valuable lessons about what is needed for an aircraft capable of high μ flight. According to Jay Carter, "This [reaching μ-1] has been our goal since we first began flight-testing in 1998. To prove our technology we needed to do something that no one else had ever done. We have had several setbacks, but no one on the team ever lost faith.
Some of the noteable accomplishments from the flight testing program include:
- First and only aircraft to achieve μ-1
- L/D of 7 @ 170 mph - twice as efficient as best pure (non compound) helicopters
- 150+ flying hours
- 1000+ takeoffs and landings
- Demonstration of zero roll takeoffs & landings
- 10,000 ft altitude
- 173 mph