DARPA uses a global hawk to aerial refuel Scaled Composites Proteus?

[bobbymike]

DARPA Testing Global Hawk Drones As Aerial Tankers

This is some cool footage of DARPA, NASA and Northrop Grumman “wake testing” an MQ-9 Global Hawk drone to test the feasibility of using unmanned jets as an aerial tankers as part of the KQ-X program.

On January 21, the team flew Scaled Composites’ Proteus test jet 40-feet behind the drone at an altitude of 45,000-feet to see how much wake the Global Hawk would leave for any aircraft trying to refuel from it and how well the two planes could maneuver while flying close together at that altitude.

This flight opens the door for an actual aerial refueling operation using two Global Hawks in the spring of 2012, according to Northrop.

“Demonstrating close formation flight of two high altitude aircraft, whether manned or unmanned, is a notable accomplishment,” said Geoffrey Sommer, KQ-X program manager at Northrop Grumman Aerospace Systems sector. “When you add autonomous flight of both aircraft into the mix, as we will do later in the KQ-X program, you gain a capability that has mission applications far beyond just aerial refueling.”

All of this is being done to see if high flying drones can be used to refuel other drones that are flying high-altitude missions that could see them staying airborne for days or longer.

Read more: http://defensetech.org/2011/03/09/darpa-testing-global-hawk-drones-as-aerial-tankers/

With video at the link.

 

[Grey Havoc]

KQ-X - Yes, That IS How They Do It (Ares blog)

As noted in the article comments, perhaps not the best method of IFR that they could have used.

 

[PlanesPictures]

"In the reverse of normal probe-and-drogue refueling, the tanker (on the left, above) is fitted with a refueling probe on the nose and the receiver (right) is equipped with a hose-drum unit under the fuselage." - similar refueling system was planned for one Russian project

 

[Hobbes]

If it's the reverse of normal probe-and-drogue refueling, the tanker would be bottom right, not top left in that picture.

 

[Jemiba]

If it's the reverse of normal probe-and-drogue refueling, the tanker would be bottom right, not top left in that picture.

Jozef quoted the caption to a photo in the link posted by Grey Havoc.
A little bit surprising to me, that tanker aircraft still aren't proposed to be unmanned. Should be one of
those tasks, which least need a crew, not to mention the danger for those manning such a high-value
target.

 

[PlanesPictures]

manned tanker is bottom right

 

[Sea Skimmer]

A big tanker is a high value target, but also one which is always going to be kept far away from the enemy, manned or unmanned precisely because of this. Taking the crew out won't make a big tanker expendable nor survivable, and elaborate defensive systems cost lots of money. Taking crew out is also expensive for little other gain. If you want an unmanned tanker that goes close to trouble, a buddy fueling system on Avenger or whatever else comes out of MQ-X would be the way to do it.

A big reason to want Global Hawk air to air refueling is that Global Hawk flies very high and having it spend lots of time cruising down and then climbing back up from 30,000ft to 65,000ft is annoying. This 45,000ft test is already much higher then a KC-135 can be expected to conduct refueling at. Its expected to operate far away from other forces, so sending out a lone big tanker, KC-707 or or whatever to refuel it would largely waste the tanker sortie as Global Hawk won't consume the entire fuel offload and the tanker isn't going to wait ten hours or more for the Global Hawk to want another drink. So all and all, very logical place to start unmanned tanker use.

 

[Hobbes]

Let's get this straight then:

In the reverse of normal probe-and-drogue refueling, the tanker (on the left) is fitted with a refueling probe on the nose and the receiver (right) is equipped with a hose-drum unit under the fuselage.

 

[Gridlock]

...and then 9 months later a little Global Hawk pops out?

 

[CJGibson]

Reverse refuelling was proposed in the early 70s for the RAF's E-2Ks and HS.748AEWs as the Victors were rather wobbly at the low speeds required to refuel the Hawkeye and reversing the roles made life easier for the faster type. Why it's required for the Global Hawk is curious.

Chris

 

[Gridlock]

I'd imagine doing it this way allows for less added weight on the recipient end, thus not impacting payload or endurance too much. Maybe a drogue is easier to integrate into any RCS than a probe, too.

 

[Hobbes]

From the article linked by Grey Havoc:

This unusual arrangement was selected for DARPA's automomous high-altitude refueling, or KQ-X, demonstration because it minimizes the number of aircraft in the fleet that would need to be equipped as tankers, Northrop says.

 

[ouroboros]

I'd imagine doing it this way allows for less added weight on the recipient end, thus not impacting payload or endurance too much. Maybe a drogue is easier to integrate into any RCS than a probe, too.

If a drone has a wet station hardpoint for fuel tanks, having a refueling hose unit that emulates a drop tank is fairly simple to implement from a hardware/plumbing perspective. Some drone concepts for internal stores weapons bay areas are provisioned for carrying a drop tank internally as a ferry option, so the remaining problem for a retrofit is how to provide sufficient power to the hose unit since a ram air power supply may not be able to get enough air movement while stuck in a weapons bay.

 

[fightingirish]

Company claims ability to embed power, data transfer capability onto refueling drogue
Icon Aerospace says their in-flight refueling drogue can be connected with power supply and telemetry cables and fibre optics for data transfer.
This allows for diagnostics, reprogramming and a host of other functions when a UAV is connected to the drogue.

Source: http://www.engineerlive.com/Design-Engineer/Aerospace/In-flight_refuelling_breakthrough/24668/