The Jet fuel in 3000m height of hose would make a pressure (at SpG of 0.8) of 240Bar or 24mPascal which is like 240kg/cm^2
The hose need only be 1cm^2 , making the weight of the fluid in the hose 3000m x 0.0001m x 0.8(SpG) = 240kg (a smaller diameter hose could be used, but the pressure would be the same)
Surprisingly the helicopter would not have to lift this since the pump (at the bottom) lifts the fuel (but the helicopter has to lift the hose - which might weigh about the same as the hose).
So not THAT hard to do.
Or you could just use an efficient helicopter and carry the fuel, depending on the payload required.
(BTW Amazing pair of articles on the same page;, US test pilots fly and like Concord, and new noise rules introduced. Trade war? who started it? I know the Germans by invading Poland ! )
Last edited by AnFI; 23rd Nov 2015 at 23:33.
Reason: seen other articles on same page