Something that cropped up in a very old NS RP I was once in and given that at least a couple of people have large airship fleets, I'm at a loss at how airships fair against radar?

Something that big would surely be picked up right?

But is there a speed thing to it given that most aircraft will be travelling much faster?

Given how hilariously large, slow, and metal that airships are, they'd probably just blind the radar operators with their echo.

"Captain! We must be under meteor attack!"
"No, 'tis an airship! Fire the missiles!"

Nah, missles are too expensive for airships,
more like AAA heaven, hell any thing upward of 20mm will practically take down an "proper" (realistic) airship.

Radar operators would mistake the airships as for riddiculously huge bomber formations
edit:oddly slow moving bomber formation

actually a proper and modern air ship could absorb quite a few 20mm round no fucking problem at all. Its not like popping a balloon.

As to radar, I think perhaps there was a time when the quality of radar and the materials of airship construction made airship difficult to detect.

To my knowledge that time is long dead, if it ever existed in practice and not just theory.

What Falls said; airships fare quite well against enemy fire. A couple of holes in the structure only make the gas leak out of the balloon, but won't cause that spectacular explosion we all remember from the Hindenburg. In fact I even heard claims that airships are resistant to direct mortar fire.

Back on topic: according to Skycat LTD, their own Skypatrol airship has a "composite construction" which "give an I/R and a radar signature as small as that of a light aircraft." So as Falls also said, the materials of an airship make them difficult to detect, and this appearently still applies today.
http://www.worldskycat.com/markets/skypatrol.html

(PS: From my tone it would also be clear to say, I really think airships have potential as a good alternative to freight planes and AWACS.)

My point with the radar wasnt so much they didnt appear massive--it was that they do not disappear.

also RCS is a bit disingenuous in that it depends on your POV to thing you are trying to detect.

As to its utility -- Airships are no longer capable combatants(if they really ever couldve been considered as such), thats really it.

I cant see a reason you couldnt use airship to loiter as AWACs and EW aircraft--especially over a fleet.

But Im no expert.

As to the shooting them down-- airships use bags, that thing you see from the outside is not what is holding the gas in, its holding the bags. Airships are compartmentalized you are not going to shoot one down easily with guns by hitting its bulk.

Dystopianus does it, to be exact. :rolleyes: I have about 80 of them.

That is sort of the more technically correct explaination of what I meant. Thanks Falls.

Whilst an airship would likely make a suitable AWAC or EW platform (though you could simply use a blimp with AWAC/EW gear slung under it), a freight aircraft? No point, it'd be hilariously slow.

Samo: Airships are faster then boats, so it's not that slow. Airships could also supply otherwise inaccessible locations or engage in anti submarine warfare.

If it's inaccessible to either jet aircraft or helicopter, I don't see how an airship would fare better. I would also imagine that a helicopter-based detection array teamed with a bomber-launched anti-sub weapon would be more effective than an airship as well.

It's probably just me with my 'airships died with the Hindenburg' mentality, and believing they aren't worth combat or supply roles in modern warfare, but I'd personally stick to my conventional and relatively contemporary methods.

For ASW at least an airship has the advantage of being able to loiter far longer than any other aircraft without refuelling, though I figure they must have gotten round the bad weather problem by now.

Did read somewhere that reckoned if the US Navy still had zeps in 1941 then they could've been used in the AEW role for Pearl Harbour.

Not really. Low carrying capacity and low altitude - and carrying capacity that drops off rapidly with altitude - makes conventional airships pretty bad in this role.





And of course yes airships are visible on radar. Whoever thought they weren't?

In regard to RCS:
There are no perfectly radar-transparent materials. Some are nearly transparent. But when talking something as big as an airship, and using modern polymer materials, you run into surface static and currents, making the surface react to radio waves.
To this adds the structure, for a modern airship it's metal, CFRP or both, and structural CFRP is reflective, though considerably less so than metal.

A blimp however could have a very low radar return. But not stealth-low.

Seriously speaking, currently considered airship applications look more towards blimps or semi-rigids. A zeppelin isn't that hard to take down, even if very well built, it's still just buying time, and not much of it.

I used to hear(read) all manner of people post about the "stealth properties" of airships. It was really fucking annoying.



Also, for the record when I say "airship" I (perhaps erroneously) include blimps and semi-rigids in that---a fully rigid airship is to my knowledge not really that modern with regards to utility.

I dont think the Skycat was supposed to be rigid.

A metal frame airship wouldn't be difficult to detect, most of the airship is transparent which just means the radar waves get in and bounce off all the shiny metal bits inside.

Its the same story as with wooden planes.

A major factor inhibiting renewed blimp use is the rising costs of helium. It used to be much cheaper, but it's a very limited resource of which only so much exists and only so much can be extracted per year. The demand from superconductor systems (like MRI machines), as well as high-end welding and chemistry, is driving the price up.
Currently the world lives on the supply US stockpiled between WWI and Cold War in anticipation of a need for airships.

BTW, keep in mind when calculating airships, they aren't filled with very pure helium, so lift is somewhat less than basic math suggests.
Hydrogen is currently explored as a substitute for helium, and it's worth considering for cargo applications. Hydrogen is about 40 times cheaper and gives slightly better lift more thanks to its purity than to weight.

A 1,000-ton cargo capacity blimp is going to cost about 1,000*($6.5-$7.5)*(2.5-3)~=$19 million in helium, which wouldn't be all that much, if not for helium's habit of leaking out everywhere and not for the need to vent it in other situations, which means you're going to need more than one fill. Multiply helium capacity by 15-20 for 25-30 year operation.

The issue is not as much building one airship, as that developing them makes for a non-future-proof investment, since increasing production scale will make them cost more, not less, and they similarly get more expensive to operate.

In Farsi, all aircraft are havâ paema ("air ships").

So yes, airplanes are visible on RADAR.

What about these hybrid airships with like lift body designs and the like --or these designs that arent shooting for lighter than air, just lighter.

I do not know much about airships beyond they dont pop like balloons just because you strafe them, and they dont disappear on radar just because they dont return like a flying stadium.

Don't know much about radar, but, I'm pretty sure that RADAR probably would impinge against the gondola.
Although maybe painting the airship with radar absorbent paint or using radar absorbant materials will work to reduce the radar signature.

But if real life militaries aren't using airships as superstealth spyplanes, then clearly there's a reason for it.

IDK. I'm not entirely sold on the idea, to be honest. The big point of airships is you don't need thrust to produce lift. In a hybrid, you do, and it's not like you are saving much size-wise - it's going to be a mere 10-15% smaller in each dimension than a full-on airship. So you go from 200mx40m to 170mx36m, it's not a big change.

On the other hand, it seems like the concept might work, if you produce lift cheaply enough, and if you don't plan on ever hovering. An advantage of hybrid airships is that you could potentially design them without a ballast system, as they always tend to sink. But that would only apply with a payload fraction of less than 20%, otherwise you still need ballast.

So, if I were building a passenger airliner, probably hybrid. A flying cruise ship... you might want that ability to hover over a city, and extra safety at sea. A cargo ship... on one hand, a hybrid can lift more in the same envelope, on the other, you lose a lot of fuel efficiency and you still need all the ballast systems. A sky crane, hybrid all the way, but it's usually outright a helicopter.

A lot of it comes down to the lift-drag efficiency of thick airfoils, so it might be more of a No Endorse question, seeing how I'm still using FoilSim for this kind of estimates, which isn't enough when talking about such thin margins between success and failure as in the case of hybrid airships.
One thing I can tell for sure is that where a pure airship doesn't work, neither will a hybrid.

Thick airfoils are "complicated," we don't really have closed form solutions for that sort of thing. (thin airfoil theory only covers up to about 10% thickness)



After a certain point, the flow just says "fuck it" to the adverse pressure gradient and separates, so you need to be clever with your aero. Air really likes doing that, and you're so big you get a whole lot of skin friction to rob energy from the flow. Hybrid doesn't seem worth it to me, not when you could just go slightly lighter and have a real airship, or just go for a helicopter or airplane at much less hassle.



I like the idea of AEW/AWACs airships, but the engineering-fu required for those things is insane. However, if you're clever, you can turn the structure of your airship into a giant radar antenna for stupidly long radar ranges. DARPA has investigated this.

EDIT:

Lift-Drag isn't horrible in 2D if you can avoid separation, but you get smacked really hard from 3D effects. You want to be really efficient and high lift. As an airship isn't going to be breaking speed records this means you need a high aspect ratio (long wingspan, short chord). Narrow lifting bodies are :/, and looong flying wings (Helios) don't make sense for airships.

I know they have, but have to call dubious on whether it would really work.

The issue is that for an AESA radar to work, you need specific element separation distances. An X-band radar with its T/R modules 15-20 feet apart isn't going to work. And covering the whole skin with modules will weigh so much that it will never come close to taking off. Not to mention it would cost something like the whole defense budget of a medium-sized country, for something that isn't really very useful.

The best you could manage is hanging 6-20 separate arrays around it in a polyhedron arrangement, but you don't need an airship for that.

Everything regarding the 'stealth' properties of wood and fabric being already covered, I shall spew a tangent:

Fun part is that they've already discovered a decent substitute that runs on a bi-mix involving 2%CO2 and 98%Argon for welding stainless. That, and Argon is super-awesome.

When that fails, add 1% Nitrogen.

Usually, it's a choice between an Ar/CO2 mix of 85/15, 90/10, and 98/2; with stuff containing a 40% He content for Nickel and SUPER-THICK aluminum (and even then you can get away with welding it in the fridge with straight argon).

And when all else fails, TiG weld it with straight argon, fit the mills with friction stir welders, or break out the fraking CO2-lasers.

---

Okay, geez, fine, I'll get back on topic...

COSTS $$$$$$$$

And historically, blimps don't run away from storms very well.

Argon is the norm for TIG welding, outside US particularly, has been for about as long as TIG welding has been used.

But some applications require helium mixtures, and while such are actually very rare, in US, due to the government liquidating national helium reserves, crude helium is available at a fixed price well below market value, so operators that have access to government supplies use it to a greater extent than elsewhere.

FSW doesn't work very well on steel, the main industrial metal, and can only produce the simplest joints. Laser welding is also somewhat specialized and not applicable everywhere. So there's still going to be a lot of demand for TIG welding.

But welding will remain elastic, it can do without helium, it's superconductor and cryogenic applications that can't.

You could cheat a bit and paint the RAM on the internal radar reflecting structures.

It still won't equal a LO craft but it will be an improvement.

The ideal balloon-WACS is arguably the aerostat design used for the JLENS radar. Compared with a blimp you can eliminate the engines/gondola/crew and save weight for the RADAR (and money on the helium).

Kyiv, the problem with RAM is that it absorbs RADAR energy, which creates waste heat.

Gas-bags do not like high pressures, and tend to leak a certain amount as an inevitable resault of trying yo contain something such as H or He.

One could maybe coat the inside of the outer shell, and pump normal air around the insides to keep the gas from expanding and leaking, but then we'd run into the problem of where to place the radar-arrays.

It would still make the skin rather expensive to maintain.

Works just fine if you use a tungsten probe with a bit of Hafnium-carbon to strengthen the Re, and FSW joints (Lap, butt, edge, and T) are still a hella lot more 'complex' than what a box of rivets of the same size can do w/o brackets (lap joint only).

But yeah, Moly-steel probes are p. suck.

And if it's steel, use arc-welding (Ar/CO2), goddamnit!

Unless they are extremely close the amount of power deposited by radars into their targets is very, very low.

Just thinking on the AEW front, barrage balloon with radar unit suspended from it?

http://www.globalsecurity.org/space/systems/jlens.htm