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There's basically two versions of in-flight refueling, probe
and drogue and flying boom. The probe and drogue trails a
fuel hose from a tanker aircraft with a small "drogue" on
the end. This provides some drag for stability. Where the
drogue ends up is determined by aerodynamics, and the
pilot
of the receiving aircraft is responsible for flying their
aircraft in such a way as to plug their probe into the
drogue to take on fuel. The flying boom method has a
movable arm on the tanker, that is inserted into the
receiving aircraft by a professional boom operator. This
method was developed for Strategic Air Command, and
makes sense in that context, larger fuel flow, much less
maneuverable aircraft and the advantage of a specialist in
the back of the tanker. The probe and drogue method
however, has a number of advantages. It's the dominant
technology, you can deploy it from diverse aircraft - using
a pylon mounted pod, you can refuel multiple aircraft and
it's cheaper.
How about a bit of both? Add an electrical power supply
and control lines running down the hose, then add a nifty
quadcopter on the end. This will have to be a high
performance unit with powerful electric ducted fans
enabling it to fully maneuver itself and the weight of the
hose around a relatively large volume behind the aircraft,
including above the usual plane of operation, thus avoiding
vortices and jet/prop wash. A selection of reference
signals from the tips of the wings and vertical stabilizer
should allow very precise station keeping and maneuvers.
Additionally, the operator inside the tanker can have
camera feeds from the Drogue-copter as well as the usual
windows etc. Now the operator can invite an aircraft into a
specific zone, then do the detailed maneuvers necessary to
connect up the fuel before leaving the drone to station
keep while the go connect another plane behind and above
the other wing. The quadcopter should be equipped to
service both probe AND boom type aircraft, and include a
screen. Because fighting a war is no reason to miss the
boat race.
Active Stabilization... but not as much fun
http://foxtrotalpha...zed-drog-1673992575
[bs0u0155, Dec 17 2015]
Helicopter in-flight refueling - not easy.
https://www.youtube...watch?v=VAdpKpppZiA
[bs0u0155, Dec 17 2015]
[link]
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// In fact, why not make the drogue
smarter? Given some sort of communication
between tanker and helicopter, the flyable drogue
should be able to compensate for small movements
of both aircraft - in effect flying itself to the
nozzle of the helicopter. The drogue should be
much more maneuverable, over small distances,
than either of the aircraft.
// |
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Yep. If we thought of it at the same time, bet it's already
been tried... |
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You know, I had considered this but I was thinking
that you're docking a pretty heavy device, another
aircraft that you've introduced into the mix and if
you screw up, you're crashing that 3rd aircraft into
the helicopter. |
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And again, kite or small 3rd aircraft carrying a hose,
you fly into the powerful downwash of a helicopter
you've got control issues. Solution would be a long
boom extending out in front of the helicopter like
they do now, but that would work with the trailing
hanging hose as well. |
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Can I admit some ignorance? They've been filling
helicopters from flying tankers for decades. What's
the specific issue about this new aircraft that's
causing problems? I got to this far in the story: |
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//helicopter refueling simply was not possible with
the A400M in its current configuration, but because
several countries were interested in ...REGISTER FOR
FREE ACCESS (VALID EMAIL REQUIRED)// |
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//What's the specific issue about this new aircraft that's
causing problems?// |
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I'm not exactly sure, but the A400M is a lot bigger and
heavier than a C130 with a lot more power. I expect there's
a bundle of small kinks to work out. |
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//another aircraft that you've introduced into the
mix and if you screw up, you're crashing that 3rd
aircraft into the helicopter.// |
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Needn't be a big problem. However the drogue
flies, it will be limited in envelope by the pipe.
And if the helicopter has a forward-protruding
probe, then the worst outcome is that the drogue
and/or probe get damaged, neither of which need
be fatal. |
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Plus, remember that in current systems the drogue
is effectively flying, but in a relatively
uncontrolled way. I'd have thought that a
computer-controlled flying drogue could be much
more stable against turbulence than an
uncontrolled one. It's one of those things where
the millisecond response time of a computer is
better than the tenth-of-a-second response time of
a human. |
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//then the worst outcome is that the drogue and/or
probe get damaged// |
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As long as when planning that crash, you avoid stuff
such as the helicopter's rotors, cabin windshield etc.
If you're only planning a loss of control within a
certain area that's one thing, if there's any way that
vehicle might leave that area by ten feet or so then
you have potential problems. |
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Putting computers in charge of the docking is fine,
but simpler and lighter is better. Case in point, the
heli refueling video. I believe the weight of the fuel
line alone pushed the helicopter down causing the
pilot to
have to pull up, overcorrect causing the probe to hit
the rotors. |
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What about trailing a couple of fuel line attached
drones behind each vehicle while they fly side by side
and they fly together and automatically link up? Then
if they crash, no big deal. Nothing's going on in front
of the aircraft. |
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Eh. Too heavy and complicated. |
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What's with the obsession with quadracopters?
The hose is being dragged behind an aircraft doing (mumble) km/h. Just give it wings with control surfaces, like a tethered glider. |
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They already to that don't they? I thought there was a
guy in the tail of the tanker flying these things into
place with wings on the boom, then they extend the
tube. Maybe they use motors and the little wings are
just
to help push the boom down. |
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