Modern "Blimps"

fretburner

Banned Member
Just about every defense website has something on either the JLENS or the LEMV. I believe these are going to be used in "uncontested" airspace being protected only for small arms fire? Anyhow, my question really is...

Why are there 2 designs, i.e. "moored" versus "not-moored" (not sure if I have the correct word).

I get that one is basically a radar to track low flying cruise missiles while the other is an ISR platform. However, can't we put the payload from the JLENS into the LEMV and vice versa? This seems to me like an LCS-1 and LCS-2 thing. It can't be that you want the JLENS to be practically "static" right?

Thanks for the replies!

Edit: Mods, kindly move this to the Army forum. That one might be more appropriate for this thread.
 
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colay

New Member
Well, for starters JLENS is an Army initiative and LEMV is/was an Air Force project so they would have been designed for different roles and missions.
 

My2Cents

Active Member
Just about every defense website has something on either the JLENS or the LEMV. I believe these are going to be used in "uncontested" airspace being protected only for small arms fire? Anyhow, my question really is...

Why are there 2 designs, i.e. "moored" versus "not-moored" (not sure if I have the correct word).

I get that one is basically a radar to track low flying cruise missiles while the other is an ISR platform. However, can't we put the payload from the JLENS into the LEMV and vice versa? This seems to me like an LCS-1 and LCS-2 thing. It can't be that you want the JLENS to be practically "static" right?
The JLENS is supposed to be as static as possible, but it is a balloon. It functions basically as a 10,000ft tall radar mast. Power for the radar is provided from the ground via the tether. You can put the other sensor packages on, they have used similar systems in Afghanistan.

The LEMV is a blimp, i.e. a balloon capable of independent powered flight, and much larger than the JLENS. The primary function being touted is as a long endurance alternative to an unarmed Predator drone, moving to where it is needed, tracking convoys, etc., but I am going to bet that if it succeeds it will be as a communications relay alternative to the overloaded satellite system. Not sure if it could support the JLENS’ radar package, it only has 16kw of power available for the radar and the downlink.
 

fretburner

Banned Member
  • Thread Starter Thread Starter
  • #4
The JLENS is supposed to be as static as possible, but it is a balloon. It functions basically as a 10,000ft tall radar mast. Power for the radar is provided from the ground via the tether. You can put the other sensor packages on, they have used similar systems in Afghanistan.
That explains it -- required power for the radar. I guess it wouldn't be such a great idea to put some sort of a generator on air, on the JLENS if it's supposed to stay for 30 days.

Is the tether there just to supply power? Or are there sensors and what not attached to it as well?

Well, for starters JLENS is an Army initiative and LEMV is/was an Air Force project so they would have been designed for different roles and missions.
I believe the LEMV is also an Army initiative.
 

My2Cents

Active Member
That explains it -- required power for the radar. I guess it wouldn't be such a great idea to put some sort of a generator on air, on the JLENS if it's supposed to stay for 30 days.

Is the tether there just to supply power? Or are there sensors and what not attached to it as well?
The only purposes of the tether is to hold the balloon in place, supply power, and communications between the radar and the ground (probably fiber optic). There are no advantages, and a huge quatity of technical difficulties, in placing sensors, etc. on the tether because it tends to twist unpredictably due to dynamic loads.
 

colay

New Member
That explains it -- required power for the radar. I guess it wouldn't be such a great idea to put some sort of a generator on air, on the JLENS if it's supposed to stay for 30 days.

Is the tether there just to supply power? Or are there sensors and what not attached to it as well?



I believe the LEMV is also an Army initiative.
You're correct, I was thinking of Blue Devil 2 which, unfortunately, seems to have been aborted, at least for now. A pity, IMO.
 

Quiller

New Member
Another useful future role for a maneuverable airship equipped with sensors would be for conducting strategic early warning surveillance and detection over vast regional hotspots. The South China Sea and East China Sea come to mind. Placing a half dozen, for example, slowly patrolling above parts of Japan, and particularly along the Ryukyu island chain would provide valuable and ongouing intel on activities in the region. Adding airships to patrol above other countries in the region friendly to the west -- e.g. South Korea, Phillipines, and Taiwan, would put a big intelligence crimp in China's projection of force in the area. Keep in mind these airships would be located above the coast of a sovereign country and not inserted into an active combat zone. Even Israel could field one or two of these above their territory as early warning post aloft to warn against ballistic missile lor aircraft attacks from several surrounding countries in that region. Forwarned is always fore-armed. Granted -- there wouldn't be that much warning since the zone around Israel is so compressed, however such an airship could detect the launch of large numbers of aircraft from airbases which, in and of itself, could add meaningful seconds warning.

Yes these platforms are vulnerable, but attempts to destroy or disable one by aircraft or missiles would themselves be detected at the outset and alert the host country to an imminent military attack.

Aside from the R&D costs to actually develop the platform itself, unit operating costs should be much less than trying to maintain a 24-7 airborne warning and/or patrol system using aircraft.

The airship envisioned would probably not be a "blimp" in the true sense, but more of a dirigible, or at least semi-rigid airship.
 

My2Cents

Active Member
Lighter than air craft may not be a good idea in Japan because of the presence the jet stream and regular typhoons.

They may also be of limited use in Southeast Asia due strong winds in the monsoon season.
 

Quiller

New Member
Lighter than air craft may not be a good idea in Japan because of the presence the jet stream and regular typhoons.

They may also be of limited use in Southeast Asia due strong winds in the monsoon season.
According to the past few years of CLOUDSAT readings, most SE Asian monsoon clouds range from 7500 to 12,000 feet high depending on eachs storm... perhaps up to 15,000 feet on occasion. A semi-rigid long-endurance airship could ride up to 20,000 feet above the clouds and turbulence. The season ranges from June through September, perhaps later. But that means for 2/3's of the year such airships could provide coverage. During monsoon season they could arguably continue to do so hovering aloft above the storm cloud layer. Passing vertically through the storm every two weeks to change crew, replenish supplies, or conduct maintenance could, admittedly, be a bit dicey depending on the circumstances. An unmanned version maneuvered by ground control could keep one up for a month or more, making the risk less.

Don't know about typhoon cloud systems... since they are tropical cyclones I suppose they can get up to 75,000 feet in some cases, which would be a problem over Japan and the Phillipines. Even so, having a couple such airships rotating on station when possible above Luzon island and the Ryukyu Islands would still be useful between the typhoons.
 

fretburner

Banned Member
  • Thread Starter Thread Starter
  • #10
If the JLENS is like a weather balloon, perhaps it really could go higher -- like the heights those weather balloons would reach out to? Though the tether and mooring station would pretty much be in trouble should I typhoon hit the area. I guess it's not such a good idea.
 

Quiller

New Member
If the JLENS is like a weather balloon, perhaps it really could go higher -- like the heights those weather balloons would reach out to? Though the tether and mooring station would pretty much be in trouble should I typhoon hit the area. I guess it's not such a good idea.
There would be no tether. At those altitudes, although it would be possible to provide a pressurized crew quarters and control area, doing so would be expensive and add significant weight issues.

An airship flying at 20,000 feet could be controlled as they control UAVs on the other side of the globe -- Any such airship could and should be maneuverable so it can change altitude and direction periodically. This isn't intended to be a static balloon floating in one spot.

Furthermore, airship design has not progressed particularly in the last century either. It is possible to design a semi-rigid airship with certain aerodynamic features that would make it more maneuveragle and survivable in changing wind conditions. One example would be to have a rigid equator, or central horizontal primary bracing structure. The helium capsules would be contained within separate shrouds above and below the "main deck" so to speak. The helium volume would thus be divided into two halves, above and below the main deck.

Better aerodynamic designs are possible. Some of these have been explored with computer simulations both for military and private luxury transportation possiblities. Triangular wedge shapes might be more survivable in storms for example.

An unmanned version could remain aloft at those heights for up to 90 days before refueling and maintenance. At least in theory.
 

My2Cents

Active Member
There would be no tether. At those altitudes, although it would be possible to provide a pressurized crew quarters and control area, doing so would be expensive and add significant weight issues.

An airship flying at 20,000 feet could be controlled as they control UAVs on the other side of the globe -- Any such airship could and should be maneuverable so it can change altitude and direction periodically. This isn't intended to be a static balloon floating in one spot.

Furthermore, airship design has not progressed particularly in the last century either. It is possible to design a semi-rigid airship with certain aerodynamic features that would make it more maneuveragle and survivable in changing wind conditions. One example would be to have a rigid equator, or central horizontal primary bracing structure. The helium capsules would be contained within separate shrouds above and below the "main deck" so to speak. The helium volume would thus be divided into two halves, above and below the main deck.

Better aerodynamic designs are possible. Some of these have been explored with computer simulations both for military and private luxury transportation possiblities. Triangular wedge shapes might be more survivable in storms for example.

An unmanned version could remain aloft at those heights for up to 90 days before refueling and maintenance. At least in theory.
Sounds like this is what you have in mind Long Endurance Multi-Intelligence Vehicle (LEMV)

I am waiting for them to perfect solar cells printed on fabric. With the top side of one of those being about 2 acres (7,000m²) the potential power generation could be huge, and an all electric design would have endurance limited only by the helium leakage rate.
 

Quiller

New Member
Try this on for size. The lightest possible volume for an airship isn't helium, nor hydrogen. it would be a vacuum. Absence of gas altogether. Problem with drawing a vacuum is it collapses it's container.

Unless... the container is exceptionally strong and able to resist collapse, and exceptionally light itself.

Studies and experiments are being done now to test rigid aerogel structures to accomplish both lightness and rigidity. Of course the problem won't be gas leaking out... but gas leaking IN. The theory goes, if a sufficiently impermiable membrane can be stretched around a rigid aerogel framework, it might be possible to pull a vacuum and have an airship that would be exteremely bouyant. Loss of gas isn't a problem... gas (air) seeping into the vacuum would be the problem, solved by being able to pump the air out as you go.
 

Quiller

New Member
Very probably, yes. The real question is, are the stealth aspects sufficiently lightweight to justify the "concealment" obtained.

Probably the first attempts to make an airship stealthy would be to abandon blimps (non-rigid roly-poly balloons) and go for airships with a rigid or semi-rigid internal support structure. The framework could allow airships to have faceted sides, for and aft. Even modern Naval ships have gone to using broad, angled-expanses of superstructure to reflect radar away from its source, to get stealth. Ships go so far as to have ladders whose rungs are diamond shaped in cross-section. You don't step on the flat plane, but on the crease at the top of the step.

Changes in "tailoring" the balloon fabric to create angles would also be possible. Instead of having a sausage shaped container, cut/join the fabric so when inflated it asumes shapes with octagonal cross-sections... or whatever shape might best provide a sum of angles for deflecting radar away from its generator.

The sorts of coatings applied to stealth aircraft could, conceivably, be applied to the exteriors of airships. The big question would be how heavy would the coatings ultimately be. (Few people think about it, but the application of paint to a large passenger jet can add thousands of pounds to its weight. That's one reason why so many jets have broad areas of unpainted aluminum.)

Presumably the maintenance on such coatings might be less costly for airships, because they move much slower and so probably would suffer less general degredation to the coating in practice.

I'm sure others of you have much more novel ideas for reducing the radar cross-section of an airship. Burying engines within the overall airship might also help to reduce infrared signatures, etc.
 

My2Cents

Active Member
Is there any way to make huge airship stealthy?
Depends. I suspect that you could select materials to make the airbag radar transparent, then apply external shaping and RAM to the engines, power plant, etc., so no reflections.

Probably you would want add some form of infrared suppression to the engines and power plant, which would be helped by the relatively low power output.
 

hiflier

New Member
Hello All,

I've had a strong interest in blimp technology and design for a number of years. I apologize for bumping this thread however I thought it would be a good way to get some direction from any of you to similar, perhaps more current, threads. If not then this one will do just fine. Thanks.
 

hiflier

New Member
The very basic thought that I've had revolves around this thread's title with it's use of the word "modern". I have been of the opinion that it would imply that a modern blimp design would be far and away different somehow than it's predecessors. And for all intents and purposes why shouldn't that be the case. Yes, there is the physics involved regarding lift vs. volume vs. speed but then I think one has to define a certain utility into the mix as well when discussing the "package". Efficiency could very well be offset by criteria that would succeed in relegating efficiency as being defined by the end result.

In other words, is success of purpose the payoff as opposed to economic balance. There will be some speculation here but then I've already read a bit in the thread therefore I would like to think that any questions or speculation that I may present will meet some experience in various fields. It is my hope then that some dialogue will be brought to the table that might give some background or credibility to some of the ideas that have been hammering away for some time.

I'd like to start off with the Center Tunnel concept and discuss facets pro and con along with some development of the concept into a real-world application. I'm not sure if this Forum has a proto-type discussion board or not nor whether I'm better on some kind of aeronautical design board and if so I would gladly accept links to any.
 
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hiflier

New Member
Ok. No comments so I'll continue. The idea of vectored thrust isn't new; nor is the idea of a propulsion for say, dirigibles placed in the horizontal axis within the interior of an airship. There was a proposal made to the U.S. Navy in 1935 by the Virginia Airship Corporation and it's successor, the Interocean Dirigible Corporation in 1938. This last one of course was just AFTER the Hindenburg catastrophe so the timing may have been the downfall for the concept as a prototype.

One other company, the National Airship Association was a competitor supposedly with a Center Tunnel design as well. To my knowledge none of the three companies quite made it off the drawing board and only the Virginia Airship Corporation got a model into the wind tunnel? So far I have been unsuccessful finding any information regarding what if anything happened to the design.

What I'm attempting here is to develop a concept model incorporating several design elements into one platform which does not necessarily incorporate a classic LTA definition. In other words, it doesn't necessarily need to be 100% lifted by a passive system like helium although it would be better suited if it was. It would do OK with say 90% lift gas and 10% as a kind of VTOL system. In that way the structure can be made more aeronautically defined and still be capable of lifting an equivalent of better payload.
 

Todjaeger

Potstirrer
A few questions immediately come to mind.

The first is, are you really interested in discussion of a "blimp" or is the desire to discuss LTA vehicle?

The second is what sort of payload (type and/or volume/mass) did you have in mind?

One of the first which comes to mind for me, would enable a LTA vehicle to fufill a role much like the blimps in military service, that of maritime surveillance.

Imagine a slow moving LTA UVA aloft near a deployed naval taskforce. Operating at 60k or 80k ft with an onboard payload of air and air/sea search radars, comms, batteries, an engine, and an upper surface covered in pv cells, the LTA UAV could provide surveillance information to the task force below of approaching air and surface contacts for days or weeks at a time, relaying the contact information to a control and processing centre in an aircraft carrier or other command asset in the task force.
 
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