Frontier Systems is close to completing the assembly of the first of two long-endurance A160 Hummingbird unmanned air vehicles (UAV), which are due to begin flight testing late in the third quarter of this year.

The US Defense Advanced Research Projects Agency (DARPA) has been funding Frontier on the A160 since early 1998, but only recently revealed the technology.

Arthur Morish, DARPA's A160 advanced technology demonstration programme manager, says dynamic testing indicates that the hingeless, rigid, variable-speed three-bladed rotor system is stable and quiet. "We are seeing very few problems," he adds. Powered by a 220kW(300hp) piston engine, the A160 has a flight control system allowing flight just above the stall.

Remotely-piloted Robinson R22 helicopters have been used to test the A160's flight control system and avionics. Over 100 flights, or 200h have been flown autonomously.

The surrogate A160 participated in military exercises, equipped with a variety of sensors, including forward looking infrared and electro-optical systems. Payloads could include synthetic aperture radar/moving target indicator and foliage penetrating radars, electronic intelligence packages and communication relays.

The initial A160 will shortly begin tethered testing in anticipation of free flight trials before the end of the third quarter using a laptop computer-size control system.

A160 flight testing will determine the feasibility of fielding long-endurance VTOL UAVs but the agency will also determine how such an aircraft would operate within the Future Combat System, working in conjunction with the much smaller organic air vehicle, which would emerge from DARPA's micro air vehicle project.

DARPA plans to demonstrate operation concepts in fiscal year 2002. About $30 million is earmarked for the A160 project.

Hummingbird is 11.3m (37ft) long and weighs 1,820kg (4,000lb). It is expected to cruise at 15,000ft (4,570m) at speeds up to 140kt (259km/h) for 5,500km (3,000nm). Endurance will be over 40h when carrying a 200kg payload.

Source: Flight International