Joy Turns To Sorrow

Carter Aviation Technologies announced they unofficially broke the Mu-1 barrier in flight-testing Friday morning. This historic first is expected to be verified over the next few weeks. Unfortunately, the aircraft suffered a hard landing in an afternoon flight test, causing extensive damage to the airframe. The crew escaped without injuries.

The CarterCopter broke the Mu-1 Barrier at 0740 Friday, June 17th, 2005. The flight test began at the Olney Airport in Texas. This is the first time in history that any rotorcraft has exceeded Mu-1.

The barrier was breeched 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 Mu-1.

With all systems stable the decision was made to proceed above Mu-1. Initial data from the flight shows that the airspeed was 170 mph and the rotor was slowed to 107 rpm giving a value of 1.02. Previously, the lowest rotor speed achieved was 115 rpm. The higher than Mu-1 flight time was just 1.5 seconds before Neal reduced the throttle to slow the aircraft, but the flight was accomplished without incident.

Mu is the ratio of the forward speed of an aircraft to the tip speed of its rotor. Normal helicopters fly at a Mu of approximately 0.3, meaning that the rotor tip speed is roughly three times greater than the forward speed of the aircraft. At a Mu of 1 the forward speed of the aircraft and the tip speed of the retreating blade are equal. The retreating blade has an air velocity at the tip of zero with reversed airflow over the entire length of the blade. At this point, the retreating blade can provide very little lift and becomes very unstable.

The significance of high Mu flight has long been understood but the design of conventional rotorcraft made it impossible. Carter's design is definitely unconventional and includes 16 patented technologies. The company claims Carter technology should allow flight speeds up to a ratio of Mu-5 (where the aircraft is traveling at speeds up to 500 mph and the tip speed of the advancing rotor blade remains under mach 0.9).

The CarterCopter is the prototype aircraft of Carter Aviation Technologies (Carter). The prototype is the technology demonstrator of Carter's Slowed Rotor/Compound (SR/C) Aircraft Technology and has been in flight-testing since 1998. Today's historic flight culminates more than 12 years of research and development and continues to validate Carter's revolutionary technology.

Jay Carter, Jr., Carter's President and Chief Development Engineer, was nearly speechless as the data reports came in from the flight. The milestone has eluded Carter for more than three years after achieving a flight of Mu-.87 in 2002. According to Jay Carter, "This (breaking Mu-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 has ever lost faith. This is amazing!"

Carter's flight data has proven to be very accurate in the past, however, as an element of a current U.S. Army contract the Army is scheduled to verify the calibration and accuracy of Carter's data retrieval system in the next few weeks. This corroboration will provide a more official determination of this milestone flight. Until then, the Carter team will anxiously wait to secure its place as having achieved one of the most significant milestones in aviation history.

The good feelings left before sundown. On an afternoon flight test around 1600, the CarterCopter reported mechanical problems and came in for an emergency landing. The aircraft descended at an above average speed until it contacted the ground. Fortunately for the crew, the landing gear was down and absorbed enough of the impact to protect the pilot and co-pilot. Initial reports are that the CarterCopter sustained extensive damage and is not repairable. More details should be released early next week. Stay tuned.

FMI: www.CarterAviationTechnologies.com