May 17, 2000
Bell Eagle Eye completes autoland tests at Yuma Proving Grounds as part of
the Navy's VTOL demonstration program
YUMA PROVING GROUNDS, Arizona, USA ( Bell Helicopter Textron Press Release ) -
Bell Helicopter Textron's Eagle Eye Tactical VTOL UAV, a tiltrotor aircraft, has successfully completed a
two phase Navy contract in the VTOL UAV Demonstration Program at Yuma Proving Grounds, AZ. During the entire program, the Bell Eagle Eye executed all applicable demonstration objectives, and expanded the flight envelope of the aircraft substantially.
According to US Navy statistics the Bell Eagle Eye completed 95% of the required data points during the testing. The two other competitors who participated in the program, Bombardier and S.A.I.C. completed 60% and less than 10% respectively.
The Bell Eagle Eye demonstrator (TR911X) flew over 70 flights during the program with one aircraft. The exit criteria called for 10 consecutive landings out 30 attempts. It exceeded that criterion by executing 10 out of 10 attempts within 2 feet of the designated landing spot, well within the 6.5 foot criteria. Despite experiencing strong winds during the test period (including one incident of strong rotational winds during a hover test in phase one), the Bell Eagle Eye experienced no mishaps.
During the second phase, the aircraft was flown automatically from an operational area, to a point in space designated as the capture station. After capturing the waypoint, the aircraft was commanded to autoland. Upon locking onto the glide-slope provided by UCARS, the aircraft then precisely flew down the glide-slope to a hover at 15 feet. It then transitioned automatically to the intended landing point where it conducted a vertical decent and perfect automatic landing. This scenario was repeated 10 times
to validate intercept and landing accuracy. The aircraft conducted each operation flawlessly. The average distance from the intended landing spot was less than one foot. The maximum distance was 2 feet.
The contract required 50 hours of land based flight tests during the first phase and flight testing with the Government's UAV Common Automatic Recovery System (UCARS) autoland system during the second phase. The program was intended to evaluate the performance and maturity of VTOL UAV aircraft and flight control systems.
Capabilities demonstrated throughout the program include:
Routine VTOL take-off and landings to a 24 foot helicopter landing spot
A launch and recovery accuracy better than 2 feet demonstrated
Automated hover and landing in winds gusting to 32 knots
Highly stable hover out of ground effect at 1100 MSL in 95 degree temperatures while carrying 210 pounds of payload and 350 pounds of fuel
Recovery at take-off gross weight
The ability to fly (cruise) at speeds up to 202 knots True Air Speed (TAS)
Cruise at 14,500 feet with a 200 pound payload (aircraft limit >20,000)
Automated multiple waypoint following with laser measured spatial in-flight accuracy averages as good as 7.1 meters using its dual redundant, fully integrated, "CA" coded GPS aided inertial navigation units. This accuracy is expected to be even better with "P" code GPS.
Demonstration of the integrated FLIR System's day / night payload that provided real time jitter free FLIR / TV images to the Ground Control Station (GCS).
Conducted 10 precise automatic landings in 10 attempts
The Eagle Eye is a tiltrotor aircraft whose proprotors permit it to take-off and land vertically. In transition to airplane mode, the counter-rotating proprotors mounted on each wing tip nacelle are rotated 90 degrees forward, thus converting the VTOL UAV into a highly efficient turboprop airplane. The Eagle Eye TR911X demonstrator is a 7/8 scale prototype aircraft built with more than 70% off-the-shelf manned-rated helicopter and common hardware parts. This strategy has led to a very reliable aircraft and a very low
maintenance requirement. Growth to the full-scale aircraft (TR911D) will be low risk, requiring a one-foot growth to each wing and about a one-foot increase in length and rotor diameter.
The air vehicle uses a highly automated, dual redundant command based flight control system, which is fully integrated with two inertial navigation systems, GPS, air data sensors, and three altimeters. A built-in test, capable of exercising all critical flight control system elements, is included. The Tactical Control System (TCS) compatible GCS includes a digitized map with multiple waypoint following as well as an easy to operate graphical man-machine interface for control and health monitoring of the
aircraft. The production vehicle (TR911D) will be capable of vertical take-off with a 200-pound payload and will carry sufficient fuel to conduct a 3-hour mission on station at 110nm, return to the originating station and have 20 minutes reserve.