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The impossibly bad 2005 film Stealth featured a dirigible-based, mid-air refueling tanker station for the stealth fighters to use.

At first, this seemed like it might have been the singular good idea in the film as a dirigible would have a very long loiter time making it ideal for fighter refueling.

But I don't think it's possible, right? What is the maximum known air speed of a dirigible vs. the lowest possible air speed for a tactical fighter?

(Note: I do think it'd be possible for helicopters and osprey to use a dirigible tanker, right, as their stall speeds can be essentially zero?)

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    $\begingroup$ A stationary (or very slow), big, fat target full of fuel. What could possibly go wrong? $\endgroup$ – Simon Jun 27 '15 at 9:11
  • $\begingroup$ If you're ferrying aircraft, you can put the big fat tanker right in the middle of atlantic where presumably there aren't that many bad guys. $\endgroup$ – RoboKaren Jun 27 '15 at 10:07
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    $\begingroup$ So now we are ferrying helicopters and Ospreys across the Atlantic? I don't think you've thought this through ;) $\endgroup$ – Simon Jun 27 '15 at 10:34
  • $\begingroup$ My question is mainly about fighters. How else do you get the across oceans quickly? In air refueling is often your best choice. $\endgroup$ – RoboKaren Jun 28 '15 at 0:13
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    $\begingroup$ Love the "tire shape thing". I refer to it as "the doughnut shaped Hindenberg", and had considered it as a portable satellite launch pad. $\endgroup$ – Robert DiGiovanni Sep 23 at 18:15
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What is the maximum known air speed of a dirigible vs. the lowest possible air speed for a [stealth] fighter?

Airship fastest speeds

According to Guinness the world record speed for an airship was 70 mph by Steve Fosset in 2004.

Guinness also say

The large rigid airships built by the USA and Germany in the 1920s and 30s could reach higher speeds (up to 140 km/h or 87 mph according to some sources), but these were never officially measured to FAI standards.

Stealth aircraft slowest speeds

The F-117 has a landing speed of 180 mph.

The F-35B is stealthy and can hover.

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  • $\begingroup$ At 140kph it's actually quite promising. With thrust vectoring and current state-of-the-art FBW, it's not impossible to hover at 140kph (even without thrust vectoring, 160kph hovering has been demonstrated in various air shows). $\endgroup$ – user3528438 Sep 23 at 16:56
  • $\begingroup$ @user3528438 isn't the definition of hovering that you have little or no forward speed? What do you mean that 160kph hovering has been demonstrated? And I think in this case, since dirigibles can remain airborne at zero airspeed (citation needed), then if the fighter can hover (my definition of hover) then, at least as far as speed goes, the two aircraft are compatible. $\endgroup$ – notloc Sep 23 at 22:02
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Another factor to be considered... getting the tanker to where it is needed.

Aerial refueling is exclusively a military thing - far too expensive for commercial use. Tankers are needed where the conflict is.

One can imagine a regional conflict brewing up in a remote location, and the air forces unable to provide support until the dirigible plodded along to the location at 70 or so mph... a few days later.

Tankers that can keep up with the fighters and ground attack aircraft not only are fast enough to refuel with the fighters at a relatively safe speed, they can also get to where they are needed at the same time the attack aircraft can.

Also, being slow and very large, a dirigible would make a very easy target.

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Feasible: yes Practical: no

Fighters without hover capability could not directly refuel from it due to the airspeed, but it could serve as a "carrier depot", semi-permanently camped out mid-Atlantic high above the clouds -- Large tankers could supply it, while small tankers would dock with it (empty), load up with fuel ready to take to an operations theater faster than a land-based tanker could manage. Alternatively land based tankers could refuel and top up to larger than take-off capacities to carry to an operations theater.

However, it would be too easy a target to be useful in any world-powers operation, so at best would serve only as a stop-gap rapid-deployment readiness capability with too large an operations cost to justify.

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You mean a dirigible as in lighter-than-air aircraft?

So it has a long loiter time - it has to get the load up there
A lighter-than-air aircraft is not designed for a payload

Nitrogen is about 5.4 liters per pound
Hydrogen is about 0.4 liters per pound
A 10,000 lb payload is a balloon about 40 meters across

The problem is once you get it up there and dump 10,000 lbs of fuel you have to get is back to the ground. Release a bunch of hydrogen to get it back to the ground is not exactly an ideal situation. Hydrogen is combustible and not cheap.

10,000 lbs is about one fighter. 100,000 lbs is about 10 planes and now 80 meters in diameter. 100 planes (1,000,000 lbs) for like a mid Atlantic fuel station would be 170 meters in diameter. It just does not seem realistic to me. If it is big enough to get the load up there it is less than stealth.

The cost of the hydrogen to float jet fuel cost more than the jet fuel itself. Hydrogen is fuel and is going to have at a minimum fuel cost. So robokaren it is produced by (simple) electrolysis of water. The water is cheap. The energy to separate the hydrogen is the cost of energy and energy is not cheap.

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  • $\begingroup$ This is factually incorrect. dirigibles have plenty of payload. $\endgroup$ – Federico Jun 27 '15 at 21:10
  • $\begingroup$ @Federico Then please explain how a "lighter-than-air" aircraft has plenty of payload? Air is pretty lite. $\endgroup$ – paparazzo Jun 27 '15 at 21:26
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    $\begingroup$ The Hindenburg had a payload twice as much: en.wikipedia.org/wiki/Hindenburg-class_airship#Specifications Useful lift: 10,000 kg (22,046 lb) $\endgroup$ – Federico Jun 27 '15 at 22:03
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    $\begingroup$ If you're using hydrogen, you "burn" it using fuel cells getting both electricity and water, which you use for ballast. Your other factual inaccuracy is that hydrogen's really cheap -- you can electrolyze it from water again. It's helium that's expensive and rare. $\endgroup$ – RoboKaren Jun 28 '15 at 2:47
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    $\begingroup$ The LEMV hybrid airship (HAV-304 / Airlander 10) obtains 40% of its lift from aerodynamic forces and its engines can provide 25% lift. So a vehicle of this sort has options other than jettisoning hydrogen in order to balance lift when payload weight is removed. Other airships use ballonets to adjust lift. $\endgroup$ – RedGrittyBrick Jun 28 '15 at 11:37

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