Defence

Piasecki Aircraft is nearing the end of its initial test run of the X-49A vectored thrust-ducted propeller (VDTP) compound helicopter.

The modified Sikorsky YSH-60F Seahawk, which now has the flaperon-equipped wings, a tail-mounted propeller with electrically activated elevator and rudder devices as well special rigging for pilot controls, had flown for 19h and 24 flights by late October, averaging two flights a week.

Graham Warwick, Flight's Americas editor, included this video of the Piasecki X-49A "Speedhawk", in his blog, The Woracle on 18 October.

The aircraft first flew in June and has reached speeds of 177kt (327km/h) in a "slight dive". Although it is similar in maximum airspeed to a standard Seahawk, Piasecki says that the VDTP exhibits lower vibration in cruise flight as well as a near-level attitude (8-10°nose-down) compared with the 20°nose-down attitude for a Seahawk at the same speed.

The X-49A can also maintain its cruise speed in a maximum performance turnaround, whereas a standard Seahawk can lose as much as 30kt during a teardrop-shaped course reversal, says Steven Schellberg, Piasecki's chief test pilot for the programme.

The US Army's Aviation Applied Technology Division, which took over the programme from the navy in 2004, is investing $3.3 million in the initial flight tests, which will end in December with the aircraft set to reach speeds of 175-180kt, the maximum allowed under the contract. The US Army is interested in technologies that can boost helicopter speeds to 200kt or more.

Piasecki will prepare a final report to be presented to the army in February, and hopes to gain additional funding to finish phase one testing and launch into phase two after an army review in March.

Phase two will include a BAE Systems-built fly-by-wire system and a General Electric T700 engine in place of the auxiliary power unit.