c0ea71 No.545921
Piss-easy to shoot down, waste of resources and staff
9e1144 No.545923
Their ability to haul lots of material in the air seems to be interesting, but I just don't know where would that be useful, other than the very northern parts of North America. You could set them up to carry quite a few shipping containers and the equipment to unload them.
c843c6 No.545927
>>545923
They really can't haul stuff, the Hindenburg could barely carry 100 people and that was with massive weight cutting measures (people had to sleep in bunks, only one toilet per 10 people etc etc)
1a0026 No.545931
>>545927
We can build airships that can carry 1,000 tons now. Thats five times larger payload than any aircraft, in fact its cargo ship sized aircraft, so construction prices over 1 billion are acceptable.
e7f677 No.545937
>>545931
I keep seeing proposals and such for using airships as high altitude surveillance drones, as they can supposedly stay airborne for several months/years and carry bigger equipment than a fixed wing aircraft.
Would such a drone werk outside of goat herding countries with no air defenses beyond CIA-supplied manpads?
Its heat signature would probably be negligible but I am unsure wether passively masking its radar signature is even possibru at that size and form factor.
b55ab1 No.545938
What do you fill it with? Hydrogen is flammable, Helium is scarce.
6d82e5 No.545939
>>545921
>piss easy to shoot down
Only from the end of WWI onwards. Before that they were flying too high, too high for fighters, and their hulls were made from cow intestines(not the Hindenburg class, bust most of WWI airships), which automatically seal themselves when punctured. Only incendiary ammunition put an end to them.
For their time they were highly advanced machines with no reliable counter.
>>545923
>>545931
You could employ them as static recon posts above your FOBs. Instead of wasting fuel having a drone circle overhead all you need to do is fill a balloon with helium and moor it somewhere. Put a camera on it, have it scan the area for any thermal signatures that come too close. If it can't get a good picture of something, it could activate a small electric engine, fly closer and investigate. Recharging the batteries could be done either by cable (mooring wire) or with solar panels on top.
Sure, bad weather could make this difficult to have the zeppelin not be ripped away, but all you need to do is secure it with multiple mooring wires, so that no matter from which direction the wind comes, there is always a mooring wire somewhat parallell with it.
Behold my MSPaint skillz.
>>545937
Heat signature would actually be quite severe. IR sensors need lots of cooling (because they are built to absorb IR radiation, which is essentially heat).
They don't need to be large. Modern stealth fighters already have radar cross-section of somewhere between 0.2 to 2 m². A tiny recon balloon, which already has a cross-section of only 2m² could have a ridiculously tiny radar cross-section.
>>545938
>Helium
>scarce
"National Helium Reserve". Google it. Thanks US tax payers for providing cheap Helium!
Prices will skyrocket soon. Nobody is producing Helium right now, and the US congress passed a bill, forcing the nation to sell off it's reserves by 2016. Only reason we are still getting it for cheap is because the US defense system, as always, is behind schedule.
If you want to become rich, invest in Helium production now.
Mark my words.
1a0026 No.545943
>>545938
>tanks huh, what are you gonna fuel them with? diesel is flammable and uranium is scarce!
Thats not an argument. There are techniques for mitigating hydrogen dangers, hindenburg was a fluke that used thermite paste as paint.
>>545937
>>545939
It would be useful over dirtgrubber states immediately, but also over some regional powers once you take out their IADS.
Floating at 20-25km keeps you above almost anything.
8fa2ce No.545947
>>545943
>Thats not an argument. There are techniques for mitigating hydrogen dangers, hindenburg was a fluke that used thermite paste as paint.
It was an argument when they could be intercepted by fighters with incendiary rounds, the question was has anything been developed since 1930 to deal with that. I assume high altitude flying like some of the other anons said.
2a0f3a No.545949
>>545931
imagine how much landing space you would need for servicing these giants. not feasible unless we are in mongolia
9e1144 No.545956
>>545939
Now that you mention it, they could work very well on borders. I'm that putting a series of outposts with good surveillance and rapid response teams would be cheaper and more effective than buildings walls and fences.
6d82e5 No.545966
>>545956
You are giving me flashbacks to the train threads.
Have recon airships placed along the train line, maybe move them along the route when the weather permits it. They report on any movement close to the line from above, and as long as there are not trees growing right next to the tracks (a simple deforestation cut would be required, but that would need to be maintained as well) the airship could have a good view for a couple of kilometers down at the tracks.
A Litening pod weighs 208 kilos, getting it off the air won't require a large envelope at all. Powering them could be accomplished with the same power-lines as used for the trains. As they are high up already they can also collect data on the current meteorological situation, relay the info to a ground system, and automatically moor when the weather gets too bad.
The whole detection could be automated as well. The camera pans along the train line constantly, and if it spots a thermal signature bigger than a large bird it sends an alert. At which point a human operator takes control of the airship, takes a look at the threat, and decides if a response team should be send out to investigate further.
6d82e5 No.545981
>>545939
How on earth did I forget to upload the image?
1a0026 No.546004
>>545949
They dont need a runway, so could theoretically land on the sea.
Im more interested in commercial applications than military…
6d82e5 No.546009
>>546004
>not deploying high flying autonomous solar stealth blimps to take pictures of the Syrian civil war from above and selling the intel to the highest bidder
Weak.
2a0f3a No.546011
>>546004
then you eliminate their main adventage over ships
which is retarded
1a0026 No.546033
>>546011
Their advantage over ships is that they dont have to go through sea locks or around continents, ensuring two to three times shorter routes. Also theyre up to ten times faster (20km/h vs 200km/h). All this results in far faster shipping times for a similar fuel cost.
There are a few kinks to work out, but drone airships are the future of commercial transport.
9e1144 No.546036
>>546033
That sounds incredibly, especially if you look at the possible political consequences. You basically couldn't embargo even landlocked countries if you don't have the willingness to shoot down aircraft, even if said aircraft is just a drone airship. And that is quite a big step to take in this pussyfied world. Even better, it has no reason to fly low and stop anywhere other than the destination, so you could carry basically whatever you want. E.g. you could load up one with enough matériel to arm a whole division and send it to the middle of Africa to trade it for raw materials.
81e530 No.546038
>>546033
They're faster and travel shorter distances, but you're more limited in what you can store in them.
>>546036
>You basically couldn't embargo even landlocked countries if you don't have the willingness to shoot down aircraft, even if said aircraft is just a drone airship.
After 9/11, the US has been pretty keen on the idea that they'll shoot down anything in their airspace not designated to be there and ask questions later.
db08d8 No.546041
>>546038
In what you can store, or how much of it?
81e530 No.546043
>>546041
Both. But more how much.
9e1144 No.546044
>>546038
>After 9/11, the US has been pretty keen on the idea that they'll shoot down anything in their airspace not designated to be there and ask questions later.
And how does it impact trade in Africa and Eurasia? You can go to quite a few places without entering their airspace.
1a0026 No.546050
>>546036
For that a smaller airship could do the job.
Ten tons of missiles purchased at $2k each in Mexico and sold for $10k cocaine value each in Nicaragua, are still four million in profits. Lets say the trip cost a million in wages, fuel, and bribes, thats still 3 million buckaroos raw yours per trip. If you make two trips a month, twenty four per year, minus four for bad weather, thats 60 million yours at end of year.
Such an aircraft could be paid off in full in just a few months worth of operation.
>>546038
Yep. There are a lot of small engineering and supply line problems with it.
Only a large company like airbus, boeing, embraer or someone nuts like Irkut could built the dozen or so of these to establish a connection between China and Europe.
9e1144 No.546058
>>546050
Well, I was thinking about an alternative for merchant submarines, so the intended role would be quietly bringing home rare earth metals and similar things from faraway shitholes that have them. But yes, criminal organizations could make use them too. I imagine it would be easier to smuggle blood diamonds from Africa if you used an airship to quietly take a small bag of them to a ship waiting at the sea.
edf45f No.546070
I wonder if they could be used as an attack vector for nuclear weapons, if they can be made ultra stealthy you could sneak some pretty big weapons across the border, if they were constructed sturdily enough they could hide in clouds that are already moving along the correct flight path.
392cd5 No.546075
>>545981
Couldn't we use the high-altitude wind for power generation too if we're going to build wires that long?
0a17a2 No.546094
>>546075
yes and you can even generate electricity by using the electrostatic differential.
3195bd No.546102
>>545981
>>546075
>>546094
>high-altitude wind for power generation
A few years ago google bankrolled a startup to do basically this cause they're edgy like that
I think this is it: https://x.company/makani/
392cd5 No.546105
>>546102
>https://x.company/makani/
Not enough balloons.
Does anyone know how big it would have to be to lift a massive tether that could transmit power, and also if lightning strikes would fry the thing?
5a0c6a No.546114
>>546075
They're already prototyping them.
3195bd No.546118
>>546105
It's basically a kite so it's really the wind is really doing all the lifting. As I recall the limiting factor was the strength of the cable (to hold the kite against high altitude winds), not the electrical capacity.
db08d8 No.546119
>>546075
>>546102
>>546105
>>546114
This looks like it will have all the problems of regular windmills, but compounded by the fact that your failure-prone turbine is now 10,000 feet in the air instead of 60.
b28968 No.546122
>>545921
>make stratospheric drone mini-blimp with cheap-ass camera with a decent zoom in
>send it on reconnaissance mission over deep enemy terittory
>enemy now has to use ten times more expensive SAM or AAM + jetfuel + fighter maintenance cost just to prevent you from stealing his secrets with a party baloon
>you can even make if from mall-bag and lego-tier plastic in order to be "stealth"
>still more versatile and far less predictable than satellites
e7f677 No.546161
>>545939
>severe heat signature
On a blimp sure, but a rigid airship should have enough interior space for a decent cooling circuit.
High altitude EW+Satcom relay vessel when?
>>546036
>be civilian logistics company operatan a fleet of high altitude cargo airships in [insert shithole conflict zone here]
>do humanitarian airdrops on behalf of the UN every now and then
>landlocked not-Iraq gets sanctioned by the United States of Israel
>bribe some local airport officials into ignoring small discrepancies in cargo weight of your ships
>have airships fly on routes over or near the besieged country
>drop small cargo pod glider drones containing satellite images and anti-semitic ryukyan woodcuts into not-Iraq amid regular aid drops over some other country nearby
6d82e5 No.546196
>>546161
Thermodynamics, my mate.
When IR radiation is absorbed by the IR sensors it must somehow be vented again. No matter how you spin it.
Using a simple IR radiator that dangles below the airship by a string and radiates the heat away safely, any IR missile would lock onto the radiator instead of the airship. If it carries two or three of these, and can lower them automatically when one is destroyed, you would require the enemy to fire multiple missiles at a cheap recon airship.
Spotting it in the first place will be hard, because it is
a)tiny
b)flies really high up
c)has a tiny radar cross section
d)doesn't produce much noise
a81709 No.546207
>>546122
>Succeed for like a week if you're lucky with wasting their resources shooting it down
>Farmers just shoot the damn things with plinking rounds afterwards
b4abeb No.546266
>>546122
Couldn't they make a similarly cheap balloon but with a knife on the end to poke yours out of the sky?
6d82e5 No.546269
>>546266
Yes, but yours has a longer knife.
Balloon warfare FUCKING WHEN?
e7f677 No.546291
>>546196
What about small rigid airships(similar in size to a current year jet fighter) with an internal cooling system akin to aerodyne related?
If it's too heavy to be practical one could also try to put the radiator on top, at 20km+ altitude it shouldn't be too obvious to enemy IRST.
>>546269
>implying we'll only have recon blimps
>implying there won't be assault dirigibles with spikes and spears attached to their hulls
3286c5 No.546340
>>546291
I'm trying to think of ideas for radar absorbing materials. Back in the day the Chinese Academy of Sciences tried to stealth aircraft by making biplane fighters with fucking silk strings lol.
874d26 No.546368
>>545920
Proper airships yes, gay blimps no.
>>545921
Actually back in the day they were quite difficult to down though nowadays that might be a different case.
47de9c No.549311
How practical would an unmanned tanker airship be?
If equipped with electric motors for propulsion+solar panels it wouldn't need to consume any jet fuel to stay airborne.
1ea803 No.549318
>>545931
>1,000 tons
>cargo ship sized
c2146e No.549320
>>549311
I don't think solar panels are that practical yet. They used diesel engines back in the day and they can still use them now. Fuel costs are very minimal compared to other transportation so it's not a big concern. The things holding back dirigibles are the same things that held them back since the Hindenburg: Helium availability, speed, and ground facilities to anchor and house them. Recent research and inventions have improved some of the inconveniences, and some of them are really interesting, but the same core problems are still there.
There's a reason most of this research is done for military contracts. Right now they're only useful in niches that don't offer great profitability, like shipping to places with poor infrastructure for more common means of transportation. You'll see mockups of balloon designs delivering food to Africans, shipping supplies to Alaska, moving military vehicles, but not the sort of late 19th/early 20th century futurism where you had balloons anchored to skyscrapers.
1a0026 No.549323
>>549318
>the only cargo ships in the world are container ships
231a4d No.549337
>>549311
Thermo electric generators may help. You are pretty high up, and the electronics/engines on board produce some heat. Compared to the -50°C you get at those altitudes you may be be able to get some power pack into your system and reduce thermal signature at the same time.
Coupled with hydrogen tanks for electrolysis power generation you could get a pretty solid platform. The real problem would probably be getting a jet fighter slow enough for it to properly refuel, without running the risk of a tiny gust from the rear stalling the thing, and sonehow allowing it to flee from an enemy attack at a reasonable sub sonic speed.
1ad31a No.549489
>>549323
Literally all cargo ships that matter hold at least one and a half orders of magnitude more cargo, 1000 tons is river-tier
1a0026 No.549611
>>549489
Being brown or green water based doesn't make it not a cargo ship.
Also 1000t is 1,000,000kg, are you sure you get that? That's about 500 cars, or whatever else they're shipping, and they can make a trip from Florida to New York in a day and a half.
Small cargo ships can achieve faster speeds for the same shipping cost as cargo ships, or they can go at the same speed for far less cost. They are also more secure than trains, which can be accessed anywhere along their route.
They're the lifeblood of coastal trade.
1a0026 No.549612
I'm just curious what you would call a vehicle that transports a million kilograms of cargo.
0ab830 No.549614
>>549612
A mobility scooter.
231a4d No.549667
1ea803 No.549678
>>549611
Ok, you like small fry, I'm not going to debate your taste. This though
>Also 1000t is 1,000,000kg, are you sure you get that?
Let me remind you we use the SI only, here in Italy
1ea803 No.549679
82dd83 No.549686
694a88 No.549688
>>549614
Ah'd slap muh knee if ah could fahnd it.
1a0026 No.549690
>>549614
>come say that to my main skin fold in real life not online see what happens
539a09 No.549879
>>549614
YOU BROKE MAH SCOOTAH
443432 No.550454
Could you use airships to relocate armoured units in a timely fashion? Think of using small ones that can carry one vehicle with crew inside and ready to go. Or would it have a hard time landing?
9e53be No.550465
YouTube embed. Click thumbnail to play.
This is a good watch right here.
c2146e No.550485
>>550454
I don't think it would be practical at that size. Some of the more modern concepts made them somewhat feasible as bulk transports for vehicles, but it would be a nightmare on an individual scale. As for landing, some modern dirigibles like the Dragon Dream had workarounds that allowed for VTOL, but I doubt it would be cost-effective to build a bunch of mini versions to transport individual vehicles.
I also wouldn't see the niche filled by such an expensive invention. Fuel isn't expensive or rare enough that you'd save money with a big, risky project like this. Combat use is out of the question. If you really needed this for non-combat, tactical use, you could probably do it with helicopters instead.
1091a2 No.550737
>>549614
Sasuga, Magyarország
4b0e07 No.550739
>>545920
I was able to pull off a motorcycle thread xd
62fc2f No.562249
>>549337
>getting a jet fighter slow enough for it to refuel
Wait a minute…
sorry if doublepost
c2146e No.562393
>>562249
VTOL would probably eat gas faster than the ship could fuel it. You would need something with a stall speed so low that it could hang behind an airship in flight or a way to capture the plane in flight like an airborne aircraft carrier. The former is basically impossible barring a plane with a very low stall speed (i.e. a glider, not a fighter jet) and the latter is so complicated and impractical that traditional methods (air bases around the world, naval carriers) are more feasible despite their extravagant costs and logistics.
62fc2f No.562413
>>562393
Rather than going full VTOL the fighter plane could be a variable sweep wing model equipped with maneuvering thrusters/lift fans/thrust vectoring producing just enough thrust to keep it flying at 150 km/h.
Or, the drone airship could carry a fleet of tiny tiltrotor tanker drones.
57ae67 No.562418
>>562393
F-18 stall is 130 miles per hour, the rigid airship in OP is 180 miles per hour.
It's definitely possible.
f844b1 No.563061
>>562418
Can the blimp's outer surface be covered by solar panels that would provide sufficient power for an electric rotor?
c9741e No.563070
>>546119
> your failure-prone turbine is now 10,000 feet in the air instead of 60.
High altitude has lots of valuable wind energy that can turn into electricity. High altitude turbines can be cost-effective. Maintenance is a cost of course, but the economics are sound.
>>546291
>What about small rigid airships(similar in size to a current year jet fighter) with an internal cooling system akin to aerodyne related?
I don't understand. Please explain in simple words or with links to websites.
>>563061
>Can the blimp's outer surface be covered by solar panels that would provide sufficient power for an electric rotor?
Yes, solar panels are awesome.
Cargo airships are awesome but I don't believe that they are ideal for most military purposes. Possibly they would be good for hauling supplies from the homeland to the safe depots. But then airplanes would probably have to take it to the battlefield.
However- some people want to use those hybrid airships. The Walrus HULA hybrid has been cancelled. Some others are behind schedule. The giant airship that looks like buttocks might be a hybrid. The killer app is "variable buoyancy." If someone can get that to work, then an army could have a giant cargo ship worth of supplies that could land anywhere. No airstrip or airport would be required. That kind of capacity would be too tempting. Military budget managers would be willing to spend any amount to get such a prize.
57ae67 No.563082
>>563061
No.
lel sorry for the short answer, i could get into efficiency of solar panels
f844b1 No.563091
>>563082
It's a fuckhuge surface area bro, not sure if enough to provide for the propulsion but you don't need networth energy-efficient panels (in the sense of needing less energy to produce than the energy provided by them in their lifetime) for this purpose.
92aa94 No.563098
You aren't going to go to war against a modern power with these things, but there is certainly a market for using them in shitstain countries that lack modern anti-air systems. Could they be used as airborne artillery platforms similar to an AC-130 but able to spend a longer time over target but cheaper? Warlord A could use it to wipe out the Toyota technicals of Warlord B.
Also they would be great for small to medium sized cargo transport in hazardous terrain areas. Think mountains or dense jungles.
Africa is going to be the best place for airships to carve out a niche in my opinion.
>>546207
Airships can fly far above small arms fire.
57ae67 No.563136
>>563091
It is helpful, but can't do it alone. Will need a small turbine and onboard fuel generating electricity in emergencies.
Reasoning:
Best solar panels can do about 10 watts per square foot in direct sunlight. Lets assume it has 8 watts per square foot in regular daylight and 4 watts per square foot in 24 hours (including night). Lets assume a 300ft long and 100ft wide ship. Gives 100,000 square feet of area and 400 kilowatts total energy.
A single goodyear blimp engine is 300kW to move it, it has 2 engines for a total of 600kW, and a goodyear blimp is only 200ft long and is a military airship not a commercial blimp, so our prospective ship might need two 500kW engines for a total of 1000kW power requirement. And to mount weapons, avionics, radars and other things would probably be another few hundred kilowatts.
Conclusions:
In other words panels would provide about 30% power continuously. That's very useful, especially for keeping the lights on and some minor station keeping, but it's not enough for operations. There are hybrid airships and drones which use solar panels to extend their operations for days more than they could on fuel alone, but its still nothing close to permanent.
We would need to triple solar cell efficiency before we could power an airship continuously using them, and we're not likely to do that in this century. It likely requires nanotech layering of graphene which is at least 50 years beyond us, and harnessing electricity from quantum tunneling, which we don't fully understand even theoretically.
62fc2f No.563142
>>563098
>Using an Airship as an AC-130
I don't think you'd want your airship to fly that low when conducting operations against Sandniggers with "stolen" MANPADs, and even if Warlord A keeps it at altitudes beyond Strela/Igla range the CIA would start selling radars+radar guided missiles to Warlord B anyhow.
Warlord A would also need a big hangar and lots of sophisticated equipment+skilled workers to keep the ship operational, which would be difficult to acquire without Russian help.
e2519f No.563149
>>546207
>>546266
>Strelo/k/ stealth balloons are active over Hadjistan.
>Hadjis create balloons with pins to pop spy balloons
>/k/ommandos create a balloon with a basket to carry a man with a rifle to pop Hadji balloons
>so on and so forth until /k/ and the goatfuckers recreate the entire history of aviation Monty Python style.
f844b1 No.563174
>>563136
Would not going nuclear help?
It would make engine design simpler since they would run solely on electricity instead of hybrid with internal combustion, it would exploit solar power better since since fuel capacity limits the range while nukulear would allow it to fly under the sun all day, thus ditching the need for batteries, plus the big size would allow a compartment for the reactor in a safe distance away from the cabin.
9bec1d No.563177
>>563174
Only if by 'nuclear' you mean a radioisotope thermoelectric generator of some description.
f844b1 No.563179
>>563177
Why necessarily? There were fully nuclear-powered bomber prototypes 50 years ago.
9bec1d No.563186
>>563179
Because closed loop nuclear power plants are heavy. Shielding. Coolant. Heat exchanger. Steam turbine. Condenser. Associated control systems.
The nuclear powered bombers you speak of used the reactors as a heat source for an otherwise conventional jet turbine. All the problems of the above, but with the added benefit of spewing radioactive exhaust wherever you go.
Meanwhile, an RTG is basically a heat engine that used a sub-critical radioactive mass as the heat source. Comparatively light, minimal shielding, zero moving parts, plug it in and it runs basically forever. You're only going to get a couple hundred watts out of it, so you use them to trickle charge your batteries when solar isn't available.
62fc2f No.563209
>>563070
>please explain
I'm referring to an evaporative water cooling system, where heated coolant is cooled down by pumping it through a series of internal tubes instead of an external radiator.
On a rigid airship with a construction like pic related the cooling pipes/tubes could be put inside the rings, with an insulated hull preventing heat leakage.
The lack of an external radiator/radiator intake would decrease the radar signature of such an airship, hopefully enough to offset the size increase and cost investment compared to a DIY tethered balloon carrying an IRST camera with its radiator hanging on a thread to serve as a missile decoy.
57ae67 No.563255
>>563174
>>563177
>>563179
>>563186
A genuine nuclear reactor would be too heavy, on the order of several tonnes too heavy… a thermoelectric atomic battery at best gives 3W/kg of fuel, which is even less effective weight-wise. I suppose a neat russian invention called an optoelectric atomic battery could provide some power for cheap weight-wise because most of the reactor is just hot gas, but it would be expensive in terms of money because it uses advanced radionuclide.
….sorry, lightest, most energetic, cheapest and overall best method is still a turbine APU running diesel.
020866 No.563421
>>563255
>A genuine nuclear reactor would be too heavy…
But it would solve the problem of the airship getting shot down, because if the enemy shoots it down over its own territory he will contaminate it.
This way the airship would become the ultimate terror weapon to take nations hostage.
98e0ec No.563428
57ae67 No.563432
>>563421
The 25-50kg/kW weight isn't the only issue. It would need to be air cooled, since it can't carry the water for the job. Which is very difficult, maybe even impossible to do safely.
The Russians are at the forefront of this tech and their nuclear cruise missiles with aircooled reactors still leak a lot of radiation…. maybe not apocalypse levels, but still pretty bad. Just a few flight tests in Siberia has resulted in measurable doses of radiation being pumped into the atmosphere, picrelated.
>>563428
RTGs are more massive per energy they provide than even fission plants. The only radionuclide generator that's lighter is the aforementioned optoelectronic/photovoltaic one, an RPG or ROG for lack of a better term. But that's powered by extremely rare materials and has an even worse volume problem.
da9a05 No.563463
>>563432
What about the molten lead reactors from things like the old Alpha class subs? I know it's heavier but supposedly it doesn't need water I'm skeptical…
4c9e89 No.563471
>>562393
>>562418
I know for a fact there are fighter sized jets that can fly as low as 30mph without stalling or falling out of the air. there's an ugly looking test plane stored at a nearby air museum. wish i could remember the name of the test plane.
2236ae No.563499
>>545920
I know Israel doesn't like them.
57ae67 No.563578
>>563463
It didn't use water as a primary coolant, but it did use it as a secondary coolant. The molten lead was used to transfer heat to the water, which prevented flash boiling/explosion of water.
We're talking direct air cooled reactors, as a primary and only coolant.
It's possible, and we've even built some air cooled reactors, the issue is safety. Closed cycle air cooled reactors have a way of setting themselves on fire because they are exposed to oxygen and there is a very high heat source nearby, there are 2 of the 3 elements needed for fire. Either that or shit out radiation if they're open cycle.
If we're willing to ignore the risk of a nuclear radioactive Hindenburg, it could be a good idea.