Automated drogue unit could also be adapted to rendezvous with manned aircraft

Maryland, USA-based UAV Refuell­ing has unveiled designs for a weapons bay-mounted drogue refuelling unit intended to allow an unmanned combat air vehicle (UCAV) to provide tanker services to other UCAVs in deep penetration, multi-vehicle operations.

The system could also be adapted to refuel manned combat aircraft, and a proposed pod-based variant would enable manned strike aircraft to refuel UCAVs, said managing director Eric Enig at the Unmanned Systems International conference in London.

“The advantage of a UCAV being able to refuel a UCAV or manned aircraft is that you have an organic solution between unmanned and manned [and] you expand the concepts of operation for the warfighter,” Enig said at the conference, organised by the Association for Unmanned Vehicle Systems International in partnership with Flight International. “You also deal with the safety issue, as you don’t have to put pilots in harm’s way.”

UAV Refuelling’s automated drogue design – the subject of a patent from the US Patent Office – would use jets of compressed air as a steering system and work in conjunction with an optical guidance sensor to manoeuvre to the receiving aircraft’s refuelling probe.

The air thrusters would have an output pressure of 20.7-34.5bar (300-500lb/in2), with these fed by an onboard storage tank holding up to 0.1m3 (4ft3) of air at 207-345bar. The air pipe would be integrated within the fuel line, with the UK’s Icon Polymer assisting in the development.

Modelling carried out by UAV Refuelling indicates the thrusters could reduce drogue motions from up to ±1.5m (5ft) to ±3mm during a 2.5s period with the carriage aircraft flying at 275kt (510km/h) at an altitude of 30,000ft.

The weapons bay system will use a retractable cowl to extend the drogue beyond the airflow field to reduce interference with the UCAV during the launch and recovery process, with the air thruster activated immediately to reduce the potential for collisions with the host air vehicle.

Enig says UAV Refuelling is seeking partners to respond to an expected broad agency solicitation for UCAV refuelling to be issued by the US Defense Advanced Research Projects Agency (DARPA) this year.

The technology could be sufficiently mature in three years to allow demonstration of inflight refuelling of the Boeing and North­rop Grumman contenders for the US Joint Unmanned Combat Air Systems programme, he says.


Source: Flight International