Quick destruction of a helium filled airship?

Question

I am writing a steampunk novel and am working on a scene where an enemy quickly overwhelms and destroys a US airship. The enemy has flying gyro sleds and a large airship of their own that is armed with rockets, air cannon and possibly electricity weapons. They need to destroy the US airship's communication and then quickly destroy the airship itself.

I am aware that during WWI, due to bullet holes leaking too slow, the Brits had trouble "shooting down" the German airships until they had incendiary ammunition but that worked because the Germans were using hydrogen. How would you all overwhelm and take down a helium airship?

Answers simply need to be plausible. I write from the H. G. Wells view point when it comes to tech.

Some specific background: Target airship is USAS Nathan Hale, a Military Airship designed primarily to fight other airships, but since Fixed wing aircraft has not been seen yet unprepared for an attack of flying Bob Sled like craft. Terrain: Over the American-Canadian border, near the St. Lawrence Seaway.

Answer 1

Condensed Gas Bombs

Popping holes in the gas cells won't do much. But, on the other hand, supposed you sent in a gas canister filled with a condensed heavy gas, like carbon monoxide. Put the canister in some harpoon-like projectile with catches on the side to the tip punches through the skin but the rest get caught on it, at which point the canister releases a massive amount of heavy gas, which vents out the helium and pumps in your heavy gas. The air cells are now filled with heavy gas, the helium is displaced, and the airship goes down.

Notes on heavy gases: I recommended carbon monoxide, as it's a bit less dense than carbon dioxide, (meaning that it displaces more helium at the same weight) but carbon dioxide can be stored as dry ice, whereas carbon monoxide can't, unless you dip below -200 Celsius, so it might be the better choice. (Credit to Logan R. Kearsley for pointing it out.) Then I did a search, and found this, which is a long list of fascinating suggestions of various fluoride derived gases, ending in WF6 or Tungsten Hexafluoride, all of which are highly reactive. So, maybe just something like SF6 if you want to go exotic.

Answer 2

The envelope of the airship is a red herring. As noted by other commenters, it is extremely hard to destroy because you're just hitting a giant pillow full of non-flammable nothing.

(There have been several instances in the modern era when stray aerostats have proven impossible to shoot down with 20mm cannon, rockets and missiles)

Go for the gondala. Go for the fuel tanks. Go for the ammunition. You are basically trying to down a WWII bomber: you don't try to make little holes in the wings to reduce its lift you kill the people on board and set off secondary explosions.

If you're feeling fancy, have chain shot to specifically target the attachments that keep the gondala suspended and cut it free from the envelope.

If you want to take out the communications first, your electricity weapon sounds like an excellent way of broadband jamming any radio signals.

Answer 3

You can use a method similar to what was used in the glorious time of sailing and wooden ships. Also in that case a single bullet was not enough to damage the shrouds and the sails, so the solution was to connect the cannon balls among them with a chain, shooting the so called chained balls.

When fired together the resulting bullet was much more effective at destroying the shrouds, the sail and the wooden parts needed for navigation.

In your case the chain made with cannon ball and their connection will:

• open a larger hole in the ship shell
• damage one or more gas cells
• take along any unfortunate crew member who happen to be on the trajectory

Answer 4

Large airships are made up of 'gas cells' held up within a support structure frame such that they displace more normal air than their own weight. Thus, they float.

However, they're not actually pressurized all that much, so simply punching a few holes in them doesn't do much. Adding more pressure to your lifting gas doesn't make it work any better, you need it to displace normal weight air for your lighter lifting gas, not stuff more of the lifting gas in so it weighs more...

If you do punch a hole in a cell, then the gas will slowly leak out and normal air will mix in, but unless you have some very big holes [or an awful lot of smallish bullet sized ones] that isn't a quick process. Crew members can wander around and patch holes after the fact.

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So what do we need to do?

We can specifically target known crew spaces with heavy weapons:

• If you have some hefty cannon like weapons on your attack craft, and attack from the bow or stern to fire shot the length of the crew compartments with enough shots, then do you even need to bring the whole ship down? [If the crew is probably all dead, and there is no AI to run the airship, then is it even really an airship anymore?]

But that's not overly impressive, and runs the risk of some crew doing the ungentlemanly thing of not actually dying to the attack...

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So what about attacking the air cells?

Simple bullets aren't that effective, but what about something more like a broadhead arrow, on steroids?

• How about "Aerial Torpedoes" - Launched weapons that are long and slender, but when their tips hit the skin of an airship large blades spring out to cut huge gashes. Some might get tangled in rigging/structure lines or frames, but a few lucky shots on several cells at once will have it sinking too quickly to recover.

• Similar attacks could be designed around slashing cables. Dragging bladed lines across the cells, possibly starting with two aircraft to wrap around, having one plane release their end so the other plane pulls a long gash.

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If you have lightening weapons, what about 'frying the frame'? - Airship won't hold up long if you turn its light frame into puddles of liquid aluminum...

Answer 5

Napalm, or a feasible technological precursor.

Wikipedia quote:

Napalm burns at the same temperature as gasoline, and for a greater duration, as well as being more easily dispersed and sticking tenaciously to its targets; these traits make it extremely effective [...] in the anti-structure [...] role.

You can spread it atop the airship structure by means of boom-and-zoom flybys; dive from high altitude, release ignited payload. Now lighter, the airplane can climb back to safety in no time.

As the skin melts, falling burning debris will stick to internal layers and keep opening up cells until the fuel runs out.

The resulting wide gashes will allow helium to leak fast enough to bring the airship crashing.

In the case the enemy implement a more heat-resilient skin you can use white phosphorus.

Answer 6

Oh, we are going to crash an Airship! And make it fast! Yee!

The Skin

First thing you focus on with Airship is the skin, peel that away and the thing will not keep afloat.

1. Lot's of small bullets. Machine guns? Na, gatling guns!
2. Napalm, apply once, fire once!
3. Hooks on ropes, let it rip! (but silly, but why not?)

The Innards

A well build Airship is kind of resistant to a sudden drop off of gasses. And should not be easily set aflame. But cannon with exploding shells will do a number on it anyhow.

1. Exploding shells.
2. Incendiary shells.
3. Grape shot (hello a lot of small holes).
4. Ball and chain shot.

The Crew

Simply put, bribe (a part of) the crew to set down the thing where you want. They will know catastrophic failure ways you cannot dream of.

(Un) Balance

(Note, not sure this will work) To be able to float in the sky, you need a fine tuned balance of being slightly lighter then the surrounding air, and to float up. And the other way around to get back to earth.

But what happens when you attach (with force) one or two auto gyro's to one end of the Airship? Unless I am mistaken, the extra weight will unbalance the whole thing and you have very little time before the whole thing plummets to its demise.

Other Idea:

And lastly, Crimson Skies has something called aerial torpedoes. Think of them like enormous rockets with way to much bang on the landing end...

Answer 7

Using this as a source: https://tvtropes.org/pmwiki/pmwiki.php/UsefulNotes/Airships

Airships are extremely resiliant compared to most other aircraft even today. Even the hydrogen filled one's are actually hard to set on fire as you need to wait for the right hydrogen oxygen mixture. A helium filled one is even more resiliant as the outer covering of airships isnt flammable. With heat you could melt the envelope but you would at best melt a big hole for the helium to escape from but if the ship uses individual gasbags the damge is limited.

I'm assuming you are using either a ridgid or semi-ridgid airship. Rather than trying to let the gas leak out I would destroy the structural integrity. If the support structure of the gasbag breaks down then so will the airship.

So your best bet is to use canon strikes at key area's like the ring structure (if any) or whatever skeleton is required to keep the airship stable and in shape. If it loses its shape and stability it'll undoubtedly crash.

As for the radio you would have to do it seperately. A canonstrike into the radioshack? That electric weapon could electrify the area and function like a crude ECM. Cut the radio antannea, sabotage, a stealthy boarding action before the attack... its your call really.

Answer 8

Roman style ballista that was modified for crowd control/riot suppression. The ballista bolt would have a blade on each side up to 6 feet in length. Fire one of those at the lift cell batteries and you'd cut huge gaping holes in the gas bladders. Add a folding feature to the bolt such that it could increase projectile range and initial velocity and deploy the blades in flight upon proximity to target.

Answer 9

Here's an idea that I haven't seen yet. Slice the whole thing in half!

You want it to spectacularly come down quick? That will do it.

The way you could do it would be to drop a razor wire from above with heavy weights on both sides, or else fire a razor cable around the whole thing and hook it back on itself and start cinching it down. You could even have a cable that doesn't expose the razor wire at first until it is really tight, and then it breaks through it's own outer sheath at a certain pressure or maybe the razor wire also has little bombs within the sheath that explode fragments of the sheath into what it is cinched around (the balloon).

In that way they could time when they want to slice the whole thing in half remotely by setting off the charges whenever they feel like it, and the whole thing just falls apart in two pieces. That would make for some drama, especially if the heroes recognize they're being caught and have a little bit of time to try and remove the lasso or bail out before it takes them down.

Answer 10

The attackers' main advantage is surprise. Use it to maximum advantage.

Attack on a moonlit night, so your pilots and gunners can see the target.

Attack from above, so the target can perhaps see silhouettes, but cannot clearly identify or range the attackers.

Create a diversion, like a bright flare, fire, or explosion about 10-15 miles away to draw the attention of lookouts and officers while the attack group closes from above and a different direction.

The first attacking sled should use special equipment to identify and slice the radio antenna (often a wire suspended in the air forward of the rear stabilizer), then get clear to observe and control the attack. The raid commander should be in this sled.

The other attacking sleds should be divided into two groups. Both should wait until the radio is cut, then take turns attacking. Group 1 uses fragmentation grenades dropped on top to shred the gasbags from above. Their goal is at least 50 grenades on target, so they need to plan on many, many more on-hand and a bit of practice beforehand. Group 2 rakes the control cabin with machine gun fire to suppress the defenses. Again, they alternate attacks, controlled by the raid commander from their observation sled. The control method can be radio or flares.

Keep the dirigible in reserve, out of sight behind a cloud unless heavy artillery is needed (which means surprise has failed). One assumes it's your sled rearming/refueling and medical point, so don't expose it unless you must.

Oh, and you should plan a sled or two for rescuing downed airmen.

It will take a few minutes for the gasbags to leak enough to notice (hence the need to suppress defenses), but once buoyancy is lost, the ship will inevitably crash. Continue to attack the gasbags (and suppress defenses) to get the fall rate you desire.

Once the mission is complete, sleds depart upon a vector that gives no clue of their origin or destination.

Answer 11

Releasing the Helium would do it...

Ramming the air ship's lift cells would do it...and possibly not damage the ramming ship if it is designed properly...like galleys of old.

Naval Ram: https://en.wikipedia.org/wiki/Naval_ram

Answer 12

Use a high explosive rocket. The rocket would be designed so the rocket catches on outside skin and seal the entry hole to some extent. When the rocket body catches, the warhead detaches and is fused to detonate three to five meters inside the airship. The warhead would be a shaped charge with two stages. The first stage would direct the blast in a narrow ring, and the second stage would be two cone shaped blasts perpendicular to the ring fired a fraction second after the first stage. An ideal shot would be fired directly behind or directly in front. With luck the first blast cuts through the skin all the way around with the second blast ripping the two separate sections apart. Shrapnel could be added to aid cutting through the skin and any internal chambers.

Answer 13

The helium in the ship might not be flamable, but the diesel that feeds the electric generators and the propellers is. Incendiary ammo will do wonders if you hit a fuel pipe.

That requires finesse, and finesse is for the weak. You've got rockets. Fire them at the gondola. Once the gondola is gone the rest of the ship is just a dead balloon drifting downwards.

Answer 14

An updated version of chain shot. It looks like an ordinary large calibre bullet, but is actually made in two halves connected by steel cable. A fuse mechanism keeps the projectile together for .3 of a second after being fired, then the spin from rifling causes the two halves to pull the line tight just before it hits the target.

Edit: Since the activation time for the round is fixed and it has a pretty short range once the cable deploys there is going to be a narrow range of ranges at which this is effective: too close and it will be out of the other side before deploying the line, too far and drag will have slowed it down too much to do damage. Maybe the pilots have a sight akin to the one used by the Dam Busters to tell them when they are at the right distance.

For added horror, consider what one of these will do to a crewmember.

Answer 15

Simple bombing should do it. Historically fighters would carry 'bomblets' (essentially aerodynamic hand grenades, which of course were time-fused not impact), but in your circumstances I would recommend a shower of small bombs like the 20-lb. Cooper bomb. Fly just above the airship from tail to nose, slightly faster than the target, and you should score several hits that send a shower of red-hot fragments throughout the structure. Probably this would just tear the gasbags apart and cause a controlled crashlanding, but it is not unlikely (since you are writing the story) that one bomb destroys a magazine or fuel store, or perhaps the control bridge or a vital structural part.

Answer 16

Harpoon it and winch it down.

One or more harpoons are deployed. Possibly these are small and the dirigible might not even know it has been hit. They might be attached stealthily. Once the ground-based winches get going, the dirigible pilot will realize they are losing altitude fast and look for a leak while jettisoning ballast. He will waste time doing that because the harpoons are directly underneath the gondola. By the time the crew figures out what is up the dirigible is on the ground and is being boarded.

Communications are disabled when the boarding party turns them off. The crew is captured alive which they appreciate. The attackers now have a mostly undamaged dirigible (and a lot of perfectly good sailors!) which will surely be useful for something later on in the story.

Answer 17

Use a fuel-air explosive, or perhaps several all on the same side of the ship. Airships tend to be rather delicate, and don't like being displaced from the side - so you set off your fuel-air bomb(s) close aboard one side of the vessel, which causes the entire vessel to bend - and hopefully to break. If you set if off close to the gondola or control room you might be able to tear the gondola completely off, and/or kill everyone inside due to shock effects. See this YouTube video for an example of one in use (although not against an airship :-)

Also note that touching one of these off in mid-air will be relatively inefficient, as the force of the explosion will be expended spherically. This means either use a BIGGER bomb, or more of them.

Or you could use a tactical nuke. Or, what the heck, use the biggest dang nuke you can find, as long as you don't like anybody in the near vicinity.

Answer 18

Fight helium with helium

Let's imagine a bullet that would pierce the envelope of the target, then explodes to release its content in fine droplet inside the said envelope.

"No point", I hear you say, "helium is not reactive and only and imaginary explosive would blow the envelope".

Yes, but the content of our bullet is liquid helium.It would then quickly vaporize inside the balloon, causing a quick drop of temperature, therefore pressure. That's more like an implosion.

The almost unarmed ship would then plummet from the skies. Possibly make a relatively soft landing as the gas heats up during the fall.