Well, looks like this airship’s gonna be tougher to bring down that I first thought. Using helium as the lifting gas means it won’t be bought down by incendiary ammo (helium’s not flammable), and the kevlar sheathing means small-arms fire won’t penetrate it anyway. The multiple gas cells means you’d have to pour literally thousands of rounds of armor piercing ammo into the airship from all sides to puncture them all, and even then it’ll probably take hours for all the gas to leak out-plenty of time for the not so good doctor to put down somewhere and escape.
Not sure even missiles will bring it down-the envelope skin may not be hard enough to set off a impact fuse (and even if it were, it would just poke a hole in one gas cell), and a proximity detonation with shrapnel would be about as useful as small-arms fire. Interesting, this airship’s passive defenses already make it tough to bring down, add some active anti-air and ground defenses, (like weapons-grade lasers), and it may well be damn near untouchable (notice I say “damn near”). Looks like the Doc knew what he was doing after all (much as I hate to say it).
Now you start to see what I had in mind. Mind you, no aircraft is invincible, and the forces generated high in the atmosphere associated with thunderstorms or tornados can still rip a ship like this to shreds. That happened several times. Still, I imagine it would wind shear detectors just like a standard jumbo jet, so it could try to avoid the storm or dangerous air.
Note: The 90 miles per hour (more like 88 mph, actually) is the ship moving in still air. Windspeed adds to it. If there were gusty 30 mph winds up there, and the ship was sailing along with the wind, it could go 110mph; going against the wind would be 60 mph max.
Not really. Kevlar is heavy so with that extra mass it’s not going to be very maneuverable. You don’t have to rupture all the gas bags, just a few in the same area (say the front) will make it unstable. Like say you take out the first 4. That would make the zep pitch forward since the back end has more lifting power and eventually make it stand on end. Of course doing something like that will damage the internal structure, maybe to the point where more gas bags get holes in them. Helium doesn’t have much lifting power. You wouldn’t need to do much damage to take out a blimp.
Well, a few notes:
1) Helium is just 8% less boyant than Hydrogen.
2) Kevlar need not be thick to be strong. As I understand it, even a thin sheet of Kevlar is still more blast resistant that steal.
3) To be honest, I don’t think you would have to destroy too many of the fifteen gas cells to crash a zeppelin. Once you kill more than 22,000 lbs lifting capacity the ship can’t climb, and the more you kill the more the ship drops.
4) The Shenendoah, an absolutely beautiful German built but American owned zeppelin, did get ripped off its mooring mast during a terrible storm, ripping off the ship’s nose. Most of the crew was on shore leave, so the ship was woefully undermanned. It got blown helplessly up into Canada until it’s minimal crew managed to regain control. There’s lots more to the story, but the ship was returned hom and repaired and put back into service.
5) My grandfather saw the Shenendoa fly over while he was farming, and he later saw the Macon or Akron (he wasn’t sure which, they looked similar) fly over too. He thought little of it, but you can only imagine how envious I was–to have seen such a thing!
By the way, in our world there was never a Graff Zeppelin III built, and Graf Zeppelin II was decommissioned not long after the Hindendburg disaster. I think there can be little argument that Graf Zeppelin I was the greatest airship in history.
1) Helium is indeed nearly as buoyant as hydrogen, which is why they were able to switch from hydrogen to helium in airships. Of course, that makes the loss of any buoyancy that much more critical.
2) Kevlar, weight for weight, has about five times the tensile strength of steel. In other words, it supports a great deal more force without warping or failing. This makes it more resistant to punctures and other kinds of piercing damage, which is why it is used in tires for racing bikes, and replaced steel plates in bulletproof vests. However, in the case of vests, it is an unfortunate fact that, after the plates are shattered by stopping a few rounds, they have to be replaced, as they are useless. The new dragonscale vests are more resistant because instead of big plates, they have many little ones, which decreases the overall weight, and makes the vest capable of taking more damage. However, when stretched thin like you’re talking about to be the film of an airship, it won’t be bullet proof, or even bullet resistant. It will be too thin. However, it is still an excellent choice for an airship skin, because it is less likely to be pierced by environmental hazards, and even slashing at it with a knife would be difficult. Given the dynamics of firing a gun from a moving platform at a moving target through wind at altitude, the airship should be safe from small-arms fire (given normal ammo), unless they were at point blank range, but rifles, machine guns, and the like would go through without problem.
And Alverant, if the structure of the airship is steel, as I would think, then you would need something more explosive to cause the structure to warp to the point where it was destroying undamaged gas chambers. Steel is a common building material because it doesn’t break easily. Think of the steel frame of a common car. You need a great deal of force to cause the trunk to deform from a head on collision. You’ll often see, in the wake of explosions and earthquakes, that the steel frame of buildings remains in many places where everything else fell around it. Assuming, of course, that the steel was good, and the engineering was up to par. But we’ll just assume so in this case because, despite the good doktor being an insufferable blowhard, he isn’t an idiot.
The structure of the ships at that time was built out of duraluminum, which was a favored aircfraft material.
I still equate the giant airship with aircraft carriers. These ships are very big and imposing, but a terrorist with a raft full of explosive can potentially blow a hole in one. Probably won’t sink, because it’s double hulled and divided into compartments, but it can be damaged.
Really, if the ship were super powerful and invulnerable, that doesn’t make it very fun for us to write about.
Actually kevlar by itself is a bit more durable but it isn’t going to be bullet proof. The way kevlar works is that threads/fibers normally have tiny fibers that split off along their lengths, sort of fuzz, even if too fine to see. That creates friction and bonds as fabric is woven. Kevlar is extremely smooth. That means when something goes to puncture it the threads that weave back and forth in that area of fabric don’t bind and tear making a hole, they stretch further. However, kevlar armor has the fabric layered between plates of solid hybrid epoxy like materials. It holds them together and keeps them from shattering in turn, and they help absorb the kinetic energy. Since the ship isn’t going to be covered with thick, hard layers of epoxy its less relevant. It’ll make it a bit more puncture resistant but that’s it.
The bigger benefit is not the tensile strength, but the low flammability of kevlar. Modern thought has the Hindenburg’s skin and flammable paint really being the reason it went up when you watch how the flame spread. Kevlar has a relatively high heat for igniting, and unless a really big fire is going can be self extinguishing. I isn’t immune to fire, but its a good start. Treat it with other chemicals, and whatever you are using to actually seal the fabric (from helium leakage), and you minimize the chance of another Hindenburg at least.
Well, while St. Elmo’s Fire is always an issue on boats and aircraft, I don’t think this ship has much chance of catching fire in conventional ways.
Kevlar is bullet resistant, as is Nomex (which has even better protection against fire) and Dyneema, but not bullet proof. It offecers good protection, but a bullet coated with, um, what was that material?, is less likely to fly apart or flatten out on impact and punch a hole through the armor.
You could cover the whole thing in one layer of 1.9 oz (or is it 1.8 oz) kevlar for something less than 13,000 lbs. (I calculated for a kind of ellipsoid shape). Presumably, that would substitute for the previous covering and therefore not cost you as much. I suspect it would actually be quite a bit lighter, so maybe you could do two layers. Maybe two layers at 45 degree angles, coated with hypalon, would stop some bullets. Particularly if softly supported so it could cave in to absorb energy more slowly. Not sure why I care.
Well, I’m glad you care enough to share your knowledge with us. To be honest, I never expected the zeppelin issue to spark a technical debate, but I’m kind of glad it did.
I’m sure the Kevlar is much lighter, because the out skin of those WWII era ships I believe was cotton and covered with dope, a substance that included aluminum.
The gas bags were made of goldbeater skin, with was composed (I kid you not) from cow intestines.
Not cow, calf. Countless baby cows perished to make the zeppelins fly. To be fair, I’m sure their other parts made delicious, delicious wiener schnitzel.
Innards don’t get near the respect they deserve as material for constructing containers. I’m not sure if till yet anyone’s made a flexible canteen that’s as effective as a stomach.
One real advantage of lighter than air craft like this is that it can potentially ascend to heights where the air is too thin to provide enough lift for traditional planes. It could even reach high enough altitudes to require enemies to use a low orbit craft to approach it, which is also high enough to avoid all non-self-propelled ground fire. ICBMs could still hit it, as could several other types of missiles, but any kind of standard anti-aircraft guns wouldn’t be able to get enough power behind the shells to do any damage to it, if the ammo could even reach it. With a pressurized cabin, this can be quite a good defense. A few anti-air defenses of its own and a good tracking system, and it can take down anything approaching it before it gets close enough to do any damage.
Ya know, no matter how hard you try to justify it, an airship built using even today’s materials still doesn’t make a practical flying base; it would simply be too heavy if it were practical by our standards (otherwise the military would have done it a long time ago). I think Scott just wanted to put an airship into his story because they’re cool (which they totally are).
Fortunately for Scott, he’s created a world which has things our world doesn’t. Who’s to say Dr. Wissenschaft couldn’t have discovered (or even created) some “neohelium” gas with far more lifting power than helium OR hydrogen?
Along with weather and altitude, temperature plays a large part in how dense a “lighter than air” gas actually is, which in turn determines how much lifting power a given amount of gas has. Airships even today are painted/doped/made of a reflective material in order to minimize the effect of the sun heating up the gas inside and causing problems with “variable buoyancy”, although this is far more of a problem for rigid airships since their gas bags cannot be allowed to expand beyond the size of the frame, yet have to be big enough to be able to lift the frame. Powdered aluminum makes an excellent reflector, which is why the Hindenburg was covered in it. Unfortunately, powdered aluminum also makes an excellent solid rocket fuel. Combined with all the other highly flammable materials, well, as Addison Bain from the above mentioned article points out, “… the moral of the story is, don’t paint your airship with rocket fuel.”
Ok, I misspoke myself slightly; while density does affect buoyancy, by itself this doesn’t create a significant problem of “variable buoyancy”. Instead the biggest problem is in allowing that factor to expand the gas bag itself, which only has a given amount of ability to expand before it is damaged – and especially in a rigid airship, which only has so much internal volume to allow for the expansion of that gas bag; hence the reflective surface on most airships, regardless of rigidity.
But if the gas bag itself were made of a material light enough to be practical, yet somehow strong enough to not have much flex or expandability, then an airship wouldn’t need to have a reflective surface, beyond the need to keep it comfortable for humans. Which still doesn’t solve the problem of not having much lift capacity for its size, but that’s a problem for a never-before-discovered super-low density “neohelium” gas to solve (or perhaps the density of neohelium is not particularly affected by temperature or altitude, making common materials practical to make the the gas bags out of).
You make valuable points, and taught me a few things about aviation in the meantime. So, while I agree with you, great, but it is standard helium that fills the ship. Helium did a fine job on American owned ships like the Shenendoah, the Los Angeles, the Macon, and Akron. All these bt the Los Angelus eventually crashed, but in each case I doubt the extra boyancy of hydrogen would have saved them.
Really, airships were such a grand idea, but plagued with impractibility from the beginning. You see that fillm of the very first ship over Lake Constance built and designed by Count Ferdinand Von Zeppelin, and it’s a wonder he got so much monetary support.
As far as Kevlar goes, it is widely considered to by good for blimp bodies, so I imagine it would be even more formidable on a metal structure.
Well, looks like this airship’s gonna be tougher to bring down that I first thought. Using helium as the lifting gas means it won’t be bought down by incendiary ammo (helium’s not flammable), and the kevlar sheathing means small-arms fire won’t penetrate it anyway. The multiple gas cells means you’d have to pour literally thousands of rounds of armor piercing ammo into the airship from all sides to puncture them all, and even then it’ll probably take hours for all the gas to leak out-plenty of time for the not so good doctor to put down somewhere and escape.
Not sure even missiles will bring it down-the envelope skin may not be hard enough to set off a impact fuse (and even if it were, it would just poke a hole in one gas cell), and a proximity detonation with shrapnel would be about as useful as small-arms fire. Interesting, this airship’s passive defenses already make it tough to bring down, add some active anti-air and ground defenses, (like weapons-grade lasers), and it may well be damn near untouchable (notice I say “damn near”). Looks like the Doc knew what he was doing after all (much as I hate to say it).
Still no defenses against a guy with a magic knife, I see.
Now you start to see what I had in mind. Mind you, no aircraft is invincible, and the forces generated high in the atmosphere associated with thunderstorms or tornados can still rip a ship like this to shreds. That happened several times. Still, I imagine it would wind shear detectors just like a standard jumbo jet, so it could try to avoid the storm or dangerous air.
Note: The 90 miles per hour (more like 88 mph, actually) is the ship moving in still air. Windspeed adds to it. If there were gusty 30 mph winds up there, and the ship was sailing along with the wind, it could go 110mph; going against the wind would be 60 mph max.
Re Magic Knife: No, no defenses for that.
Not really. Kevlar is heavy so with that extra mass it’s not going to be very maneuverable. You don’t have to rupture all the gas bags, just a few in the same area (say the front) will make it unstable. Like say you take out the first 4. That would make the zep pitch forward since the back end has more lifting power and eventually make it stand on end. Of course doing something like that will damage the internal structure, maybe to the point where more gas bags get holes in them. Helium doesn’t have much lifting power. You wouldn’t need to do much damage to take out a blimp.
Well, a few notes:
1) Helium is just 8% less boyant than Hydrogen.
2) Kevlar need not be thick to be strong. As I understand it, even a thin sheet of Kevlar is still more blast resistant that steal.
3) To be honest, I don’t think you would have to destroy too many of the fifteen gas cells to crash a zeppelin. Once you kill more than 22,000 lbs lifting capacity the ship can’t climb, and the more you kill the more the ship drops.
4) The Shenendoah, an absolutely beautiful German built but American owned zeppelin, did get ripped off its mooring mast during a terrible storm, ripping off the ship’s nose. Most of the crew was on shore leave, so the ship was woefully undermanned. It got blown helplessly up into Canada until it’s minimal crew managed to regain control. There’s lots more to the story, but the ship was returned hom and repaired and put back into service.
5) My grandfather saw the Shenendoa fly over while he was farming, and he later saw the Macon or Akron (he wasn’t sure which, they looked similar) fly over too. He thought little of it, but you can only imagine how envious I was–to have seen such a thing!
By the way, in our world there was never a Graff Zeppelin III built, and Graf Zeppelin II was decommissioned not long after the Hindendburg disaster. I think there can be little argument that Graf Zeppelin I was the greatest airship in history.
1) Helium is indeed nearly as buoyant as hydrogen, which is why they were able to switch from hydrogen to helium in airships. Of course, that makes the loss of any buoyancy that much more critical.
2) Kevlar, weight for weight, has about five times the tensile strength of steel. In other words, it supports a great deal more force without warping or failing. This makes it more resistant to punctures and other kinds of piercing damage, which is why it is used in tires for racing bikes, and replaced steel plates in bulletproof vests. However, in the case of vests, it is an unfortunate fact that, after the plates are shattered by stopping a few rounds, they have to be replaced, as they are useless. The new dragonscale vests are more resistant because instead of big plates, they have many little ones, which decreases the overall weight, and makes the vest capable of taking more damage. However, when stretched thin like you’re talking about to be the film of an airship, it won’t be bullet proof, or even bullet resistant. It will be too thin. However, it is still an excellent choice for an airship skin, because it is less likely to be pierced by environmental hazards, and even slashing at it with a knife would be difficult. Given the dynamics of firing a gun from a moving platform at a moving target through wind at altitude, the airship should be safe from small-arms fire (given normal ammo), unless they were at point blank range, but rifles, machine guns, and the like would go through without problem.
And Alverant, if the structure of the airship is steel, as I would think, then you would need something more explosive to cause the structure to warp to the point where it was destroying undamaged gas chambers. Steel is a common building material because it doesn’t break easily. Think of the steel frame of a common car. You need a great deal of force to cause the trunk to deform from a head on collision. You’ll often see, in the wake of explosions and earthquakes, that the steel frame of buildings remains in many places where everything else fell around it. Assuming, of course, that the steel was good, and the engineering was up to par. But we’ll just assume so in this case because, despite the good doktor being an insufferable blowhard, he isn’t an idiot.
Good Points All.
The structure of the ships at that time was built out of duraluminum, which was a favored aircfraft material.
I still equate the giant airship with aircraft carriers. These ships are very big and imposing, but a terrorist with a raft full of explosive can potentially blow a hole in one. Probably won’t sink, because it’s double hulled and divided into compartments, but it can be damaged.
Really, if the ship were super powerful and invulnerable, that doesn’t make it very fun for us to write about.
Wow – I nailed the kevlar and I’ll take half-credit on the engines.
I gotta stop thinking like Herr Doktor…
Scary! Don’t think like him!
Actually kevlar by itself is a bit more durable but it isn’t going to be bullet proof. The way kevlar works is that threads/fibers normally have tiny fibers that split off along their lengths, sort of fuzz, even if too fine to see. That creates friction and bonds as fabric is woven. Kevlar is extremely smooth. That means when something goes to puncture it the threads that weave back and forth in that area of fabric don’t bind and tear making a hole, they stretch further. However, kevlar armor has the fabric layered between plates of solid hybrid epoxy like materials. It holds them together and keeps them from shattering in turn, and they help absorb the kinetic energy. Since the ship isn’t going to be covered with thick, hard layers of epoxy its less relevant. It’ll make it a bit more puncture resistant but that’s it.
The bigger benefit is not the tensile strength, but the low flammability of kevlar. Modern thought has the Hindenburg’s skin and flammable paint really being the reason it went up when you watch how the flame spread. Kevlar has a relatively high heat for igniting, and unless a really big fire is going can be self extinguishing. I isn’t immune to fire, but its a good start. Treat it with other chemicals, and whatever you are using to actually seal the fabric (from helium leakage), and you minimize the chance of another Hindenburg at least.
Well, while St. Elmo’s Fire is always an issue on boats and aircraft, I don’t think this ship has much chance of catching fire in conventional ways.
Kevlar is bullet resistant, as is Nomex (which has even better protection against fire) and Dyneema, but not bullet proof. It offecers good protection, but a bullet coated with, um, what was that material?, is less likely to fly apart or flatten out on impact and punch a hole through the armor.
You could cover the whole thing in one layer of 1.9 oz (or is it 1.8 oz) kevlar for something less than 13,000 lbs. (I calculated for a kind of ellipsoid shape). Presumably, that would substitute for the previous covering and therefore not cost you as much. I suspect it would actually be quite a bit lighter, so maybe you could do two layers. Maybe two layers at 45 degree angles, coated with hypalon, would stop some bullets. Particularly if softly supported so it could cave in to absorb energy more slowly. Not sure why I care.
Well, I’m glad you care enough to share your knowledge with us. To be honest, I never expected the zeppelin issue to spark a technical debate, but I’m kind of glad it did.
I’m sure the Kevlar is much lighter, because the out skin of those WWII era ships I believe was cotton and covered with dope, a substance that included aluminum.
The gas bags were made of goldbeater skin, with was composed (I kid you not) from cow intestines.
Not cow, calf. Countless baby cows perished to make the zeppelins fly. To be fair, I’m sure their other parts made delicious, delicious wiener schnitzel.
Innards don’t get near the respect they deserve as material for constructing containers. I’m not sure if till yet anyone’s made a flexible canteen that’s as effective as a stomach.
One real advantage of lighter than air craft like this is that it can potentially ascend to heights where the air is too thin to provide enough lift for traditional planes. It could even reach high enough altitudes to require enemies to use a low orbit craft to approach it, which is also high enough to avoid all non-self-propelled ground fire. ICBMs could still hit it, as could several other types of missiles, but any kind of standard anti-aircraft guns wouldn’t be able to get enough power behind the shells to do any damage to it, if the ammo could even reach it. With a pressurized cabin, this can be quite a good defense. A few anti-air defenses of its own and a good tracking system, and it can take down anything approaching it before it gets close enough to do any damage.
That was the German airship tactic in WWI, flying way higher than the airplains could. It worked relatively well.
Of the men who served on ships like this during the war, 50% died in action. Half!
Ya know, no matter how hard you try to justify it, an airship built using even today’s materials still doesn’t make a practical flying base; it would simply be too heavy if it were practical by our standards (otherwise the military would have done it a long time ago). I think Scott just wanted to put an airship into his story because they’re cool (which they totally are).
Fortunately for Scott, he’s created a world which has things our world doesn’t. Who’s to say Dr. Wissenschaft couldn’t have discovered (or even created) some “neohelium” gas with far more lifting power than helium OR hydrogen?
As for airships of old (most notably the Hindenburg), check out this article:
http://www.esdjournal.com/articles/blame.htm
Along with weather and altitude, temperature plays a large part in how dense a “lighter than air” gas actually is, which in turn determines how much lifting power a given amount of gas has. Airships even today are painted/doped/made of a reflective material in order to minimize the effect of the sun heating up the gas inside and causing problems with “variable buoyancy”, although this is far more of a problem for rigid airships since their gas bags cannot be allowed to expand beyond the size of the frame, yet have to be big enough to be able to lift the frame. Powdered aluminum makes an excellent reflector, which is why the Hindenburg was covered in it. Unfortunately, powdered aluminum also makes an excellent solid rocket fuel. Combined with all the other highly flammable materials, well, as Addison Bain from the above mentioned article points out, “… the moral of the story is, don’t paint your airship with rocket fuel.”
Ok, I misspoke myself slightly; while density does affect buoyancy, by itself this doesn’t create a significant problem of “variable buoyancy”. Instead the biggest problem is in allowing that factor to expand the gas bag itself, which only has a given amount of ability to expand before it is damaged – and especially in a rigid airship, which only has so much internal volume to allow for the expansion of that gas bag; hence the reflective surface on most airships, regardless of rigidity.
But if the gas bag itself were made of a material light enough to be practical, yet somehow strong enough to not have much flex or expandability, then an airship wouldn’t need to have a reflective surface, beyond the need to keep it comfortable for humans. Which still doesn’t solve the problem of not having much lift capacity for its size, but that’s a problem for a never-before-discovered super-low density “neohelium” gas to solve (or perhaps the density of neohelium is not particularly affected by temperature or altitude, making common materials practical to make the the gas bags out of).
You make valuable points, and taught me a few things about aviation in the meantime. So, while I agree with you, great, but it is standard helium that fills the ship. Helium did a fine job on American owned ships like the Shenendoah, the Los Angeles, the Macon, and Akron. All these bt the Los Angelus eventually crashed, but in each case I doubt the extra boyancy of hydrogen would have saved them.
Really, airships were such a grand idea, but plagued with impractibility from the beginning. You see that fillm of the very first ship over Lake Constance built and designed by Count Ferdinand Von Zeppelin, and it’s a wonder he got so much monetary support.
As far as Kevlar goes, it is widely considered to by good for blimp bodies, so I imagine it would be even more formidable on a metal structure.