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Fuel Drones

The drop tank that lived
  [vote for,

Fuel drop tanks are relatively small, expensive and risk falling on civilians. Air tankers are very expensive, often need to be supported on and take off from land, and are valuable targets in wartime.

This fairly large companion UAV would consist mostly of a large fuel tank. It would be carried like a drop tank, but its wings, engine, and integrated control surfaces would compensate for much to all of its weight. At its own bingo fuel it would drop off the aircraft it supported and return and land on its own. Optionally it could take off and attach on its own. The combination of these features is a carrier launched, inexpensive, expendable range extender for carrier-launched aircraft.

Voice, Jun 18 2022

Military Gliders https://en.wikipedi...iki/Military_glider
For transporting stuff [neutrinos_shadow, Jun 19 2022]

Self propelled batteries [pashute, Jun 21 2022]

drive-in batteries [pashute, Jun 21 2022]

Could be adapted https://www.therail...s-another-rm-scoop/
[pocmloc, Jun 21 2022]

Pretty much baked, except these don't attach at launch https://en.wikipedi...eing_MQ-25_Stingray
[Voice, Jun 28 2022]


       [+] Short landing gears limit the maximum size of this thing. It might be better to drag the drone behind the jet (like glider tow) but instead of a rope use a fuel hose. This will also double as a anti missile decoy.
ixnaum, Jun 18 2022

       Come to think of it, if the drone has its own propulsion it could be in front as well. When empty, the drone could go fuel up at a tanker and then return back into the hot zone to keep repeating this dance indefinitely. Being a drone and having a link with the human operated jet, it can mirror manuvers so that it stays hooked up in formation within 2 or 3Gs
ixnaum, Jun 18 2022

       Drop tank with a largish parachute?
RayfordSteele, Jun 18 2022

       [ixnaum]; you're in good form lately! An extra tank towed as a glider is brilliant. Extant technology, proven concept; just not sure about high-speed towing (behind a fighter, for example...).
neutrinos_shadow, Jun 19 2022

       Drones that don't fight but top up fighters at every opportunity could be a real game changer.
Voice, Jun 19 2022

       I had the same idea some years ago, only on the ground, for electric cars. I'll look for it and post a link. Done.
pashute, Jun 21 2022

       How about a fire hose that squirts gasoline into a passing race car so it doesn't have to stop?
Voice, Jun 21 2022

       [voice] no need for a hose, see link
pocmloc, Jun 21 2022

       So a little like the self-landing SpaceX boosters? Interesting. My initial impressions are that the engine/wings should be off/folded. Fighters have an excess of power and if fuel is available, we don't need multiple extra sources of thrust and the aerodynamic consequences of multiple wing structures in close proximity.   

       The most common drop tank is probably the 610 gallon one used by F15s, and modified for the F22 amongst others. It wouldn't take much to add a folding wing & tail section derived from existing cruise missile/glide bombs. The navigation is trivial commercial stuff these days. What you would want is power. In order to maintain complete mission flexibility, you can't have requirements to climb to altitude to allow a glide return, that may not be possible anyhow. So we need an engine. The obvious candidate is a cruise missile engine. ~160lb or so for the Williams F112, plenty of thrust, established, already in the inventory.   

       What's unknown to me at least, is how good they are for repeated use, they're designed as a one-shot weapon engine. They're turbines, which come with turbine costs, and you simply don't need that much power. Something like an adapted 2-stroke dirtbike engine should be enough, in the ~30bhp range, although that can't use jet fuel.   

       Landing gear should probably just be a spring-loaded skid. These things will still end up semi-disposable.   

       The biggest problem, and one I see as fairly insurmountable. Is that they look to all intents and purposes, like cruise missiles. Do you want your forward operating airbase to be comfortable with a constant stream of incoming cruise missiles? "Is that one a fuel tank? Maybe the IFF is faulty, ask Frank in.... BOOM!!"   

       //ust not sure about high-speed towing (behind a fighter, for example...).//   

       Drop tanks leave an aircraft with much, but obviously not all, the original performance. You can watch drop-tank equipped F15/16s yanking & banking around the Welsh valleys for example. A towed system wouldn't allow that. The thing would constantly be in and out of vortices and would convey odd oscillations to the parent aircraft. Only suitable for straight and level flight, possibly useful for a bomber, but why not just make the bomber bigger, refuel it or add drop tanks?
bs0u0155, Jun 28 2022

       Dammit, Frank. That one was on you.
pertinax, Jun 29 2022


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