# How viable are Airborne Aircraft Carriers on my alien world?

I have made a world that is a massive flat plane, with the surface gravity and atmospheric pressure of Titan, but a composition similar to Earth. There is one race, humans. Humans have a problem similar to the one the Soviets encountered in world war 2. The long distance aircraft that have lots of fuel aren't easy to maneuver. The short distance aircraft are easy to maneuver, but lack the fuel to go the massive distances into enemy territory to defend the 'bomber' style aircraft. If my humans were to create a airborne aircraft carrier, would it be viable in long distance war? The aerodynamics of a high pressure atmosphere and low gravity world is confusing. A plane could likely get larger, and therefore hold more fuel, and a small plane would be even more maneuverable, and though likely outside the scope of my question, a number of how many planes you could fit on a plane may help with answering how viable such a carrier would be.

For clarification: Titan's average surface atmospheric pressure is 1.5 Bar (147 kPa). The intention is to use a "heavier than air" aircraft carrier rather than an airship aircraft carrier.

• The atmosphere of Titan is not "high pressure" in any way; the atmospheric pressure is only 1.5 atm. P.S. If there is a need for long range fighter aircraft, then the engineers will surely find a way to make them happen. For example, the Russian Sukhoi Su-57 has a range of 3,500 km (2,200 miles) with internal fuel only, or 4,500 km (2,800 miles) with disposable external fuel tanks. Commented Jan 19 at 20:01
• @AlexP Wikipedia says 1.5 Bar. Commented Jan 19 at 20:03
• By a happy coincidence, bar and atm are almost the same thing, so that in practice the two units are used indifferently. (1 atm is 1.013 bar.) Commented Jan 19 at 20:09
• what-if.xkcd.com/30 may be helpful. Commented Jan 19 at 20:12
• How flat is flat? Low gravity and high pressure mean you can land at really low speed, and flat plains are pretty good low speed airstrips. You don't need an aircraft carrier if the world is a runway.
– g s
Commented Jan 21 at 22:14

## 4 Answers

The classic solution for this problem (since the 1950s, though it could have been done by 1940 if it had been needed, with a probe and drogue system like everyone other than the USAF uses) is in flight refueling.

Some of your "bomber" aircraft carry internal fuel tanks dedicated to pumping fuel into escort fighters instead of bomb load -- and thus extend the escorts' range to that of the bombers. As you near the target, the tankers will hang back while the fighters and actual bombers finish the mission, and then they'll be (relatively) safe to ensure the fighters can get home again.

Unlike the Soviet solution, this doesn't require building a huge fighter that's still fast and maneuverable, keeping the escort craft comparable to the interceptors they'll be fighting off.

• This makes me wonder how large such an aircraft could get... Commented Jan 19 at 20:34

The Russian's answer to this problem in the 1960's was to make a long-range fighter aircraft: the Tupolev Tu-28. They had a 5000 Km front to defend, mostly over barely inhabited territory, so increasing the range of the aircraft greatly reduced the number of aircraft they had to make. In their case, the longer interception time was not a problem.

There have been piggy-back aircraft, and aeroplanes hung from airships. The most recent serious attempt that I know of was the Boeing 747-AAC, a Jumbo Jet containing 10 stacked small fighters that could be launched in the air.

This seems to be an idea that gets dusted off every few decades, but it has never really worked. Packing all your aircraft into one target does not seem healthy. It works for a conventional aircraft carrier ship, because these can be massive and carry substantial defences.

• Does my world's environment effect the viability at all? Commented Jan 19 at 20:50
• I can't see that it does. The distances, the gravity, and the air pressures are similar to Earth. The atmosphere is 5% methane, and most of the rest is nitrogen, so the aircraft fuel would probably be oxygen. One molecule of methane will combine with two molecules of water, so that is equivalent to flying on earth with a 10% oxygen atmosphere. For the same fuel/air mixture, you would be flying through roughly twice as much nitrogen which would increase the drag. I cannot be sure but it is hard to see anything that makes flying easier on Titan, so the aircraft range will probably be smaller. Commented Jan 20 at 15:45
• The gravity is 0.14. That is around 7 times lighter then on Earth. The Atmosphere has the same composition as Earth, but is 50% denser, like on Titan. Commented Jan 20 at 17:31
• The gravity is a lot less, increasing the range of the aircraft, and the aircraft could fly more slowly without stalling. The atmosphere is thicker so the drag would be greater, but this is offset by flying more slowly. Oxygen has more mass than the equivalent energy in conventional aircraft fuel. All these differences affect all aircraft on both sides. If putting lots of aircraft on a bigger aircraft a a bad idea on Earth, it will probably be a bad idea on Titan IMHO. Commented Jan 20 at 19:33
• This makes sense. However, this may effect the overall size of a plane and the balloon to cargo ratio of airships, which means I can store hundreds of inflatable airplanes! (This is a bad idea, but not as bad as it sounds.) Commented Jan 20 at 20:06

Airships.

In-air refueling is a good option on earth, but with a denser atmosphere and lower gravity it becomes easier to make airships that carry a lot of weight and planes.

Make no mistake, airships are slow compared to aircraft, but even the Hindenburg could reach 120km/h. We actually build 2 carrier airships in the history of humanity, and while their design wasn’t very good the possibility of them working is there, especially since with lower gravity and higher density of air it becomes easier to land and take off from short runways. Hell most WWII aircraft could likely take off by virtue of the speed of the airship alone.

This gives the option of carrying multiple aircraft into combat. Don’t expect the amount carried by aircraft carriers, but don’t expect these carriers to be as expensive either.

# Not a bad idea but certainly very difficult

You can’t have short-range aircraft going cross-disk to attack your enemies, they’d run out of fuel, but your long-range craft are hard to maneuver. Besides the immense cost of building them, floating aircraft carriers could be the solution.

That is, if you have a propulsion system that could keep them afloat for long periods of time (which not even we in the real world have).

It would be easier to have a Marvel-style helicarrier system that can float for a little bit over land but mostly moves through the water or over land, only flying when it needs to for any reason: conserving fuel for the rockets or jet engines or turbines that keep it afloat would be key to keeping it feasible.

Wait, you’re on Titan?

Oh, then you’ll definitely need rocket engines. Propellers won’t work; atmospheric pressure is too high (propeller blades would be too hard to push and/or would burn up).

RS-25 rocket motors (the same kind used on the United States’ Space Shuttle and Space Launch System) produce about 1.86 meganewtons of thrust with a specific impulse of around 366 seconds. So, carrying many hundreds of tons of fuel with you, a few RS-25 engines will keep a 1,000-ton helicarrier above the ground for a few minutes, given Titan’s lower gravity; maybe a few hours if you’re willing to handwave a more efficient rocket engine.

• Titan has 1.5 bars as average surface pressure. Commented Jan 19 at 19:53
• Rocket will work less well than they would on Earth (where they're tool fuel-hungry to be practical for anything other than orbital launchers and sounding rockets -- and orbit won't happen on a flat world). Propellers will work better at 1.5 bar (though they'll also give up more energy to blade drag and their size will be strictly limited to have subsonic tips). Commented Jan 19 at 20:19
• I mean to say that propellers still won't work well enough; lifting an entire aircraft carrier into the sky means providing probably several meganewtons of thrust on ascent and propellers are limited by their speed, which when increased can threaten damaging the blades (or worse, in a dense atmosphere like Titan, burning them). Commented Jan 19 at 20:35
• @controlgroup To clarify, I meant a aircraft that carries planes, not the boat type. Commented Jan 19 at 20:45
• @controlgroup As far as I know, propellers work well in water, which is even denser. Nasa is planning a second mission to Titan and using a helicopter is part of the plan. nasa.gov/news-release/… Commented Jan 20 at 15:35