proteus

Picture: Proteus in flight in 2002 in the Department of Energy’s Atmospheric Radiation Measurement - Unmanned Aerial Vehicle (ARM-UAV)* Program.

The Scaled Composites Model 281 Proteus is a tandem-wing high-endurance aircraft designed by Burt Rutan to investigate the use of aircraft as high altitude telecommunications relays. The Proteus is actually a multi-mission vehicle, able to carry various payloads on a ventral pylon. An extremely high-efficiency design, the Proteus can orbit a point at over 65,000 feet (19,800 m) for more than 18 hours. It is currently owned by Northrop Grumman.

Proteus has an all-composite airframe with graphite-epoxy sandwich construction. Its wingspan of 77 feet 7 inches is expandable to 92 feet with removable wingtips installed. Proteus is an "optionally piloted" aircraft ordinarily flown by two pilots in a pressurized cabin. However, it also has the capability to perform its missions semi-autonomously or flown remotely from the ground. Under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, NASA's Dryden Flight Research Center assisted Scaled Composites in developing a sophisticated station-keeping autopilot system and a satellite communications (SATCOM)-based uplink-downlink data system for Proteus' performance and payload data. The Proteus wing was adapted for use on the Model 318 White Knight carrier aircraft, which is the launch system for Rutan's Tier One spacecraft and the DARPA X-37.

General characteristics

Crew: Two (pilot & co-pilot)
Length: 56 ft 4 in (17.17 m)
Wingspan: 77 ft 7 in (23.65 m)
Height: 17 ft 7 in (5.36 m)
Wing area: 487.7 ft² (including canards) (45.31 m²)
Empty weight: 5,900 lb (2,700 kg)
Loaded weight: 12,500 lb (5,700 kg)
Powerplant: 2× Williams International FJ44-2 , 2,300 lbf (10.2 kN) each

Performance

Maximum speed: 274 knots (315 mph, 507 km/h)
Range: 415 nm (480 miles, 770 km)
Service ceiling: 60,000 ft (18,300 m)
Rate of climb: 6,000 ft/min (30 m/s)
Wing loading: 26 lb/ft² (128 kg/m²)
Thrust/weight: 1.8 N/kg

*Proteus has been used in a number of deployments as a part of a project sponsored by the DOE's Atmospheric Radiation Measurement program and the Sandia National Laboratories to study cirrus clouds in the upper atmosphere. During these flights, the aircraft was equipped with over 20 sensors mounted on five different parts of the aircraft. In November 2002, Proteus participated in another phase of the project, flying from Ponca City. In October, 2004, Proteus operated out of Fairbanks, Alaska, and in February, 2006, the aircraft was deployed to Darwin, Australia.