Improvised Incendiary Device

cmhbob

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I need to blow something up. :) Sort of.

My heroes are in a private plane (Mitsubishi MU2) with the pilots. The junior bad guy has about 15 minutes or so to conjure up some sort of improvised device that will ignite without further action in about 30 minutes or so (so about 15 minutes after they take off). He's a flightline guy at a smaller airport. He's got access to avgas, JP4, and various other petroleum products as well as a variety of lawncare products and devices. Device will be placed in an interior storage area in the aft part of the cabin. I basically need to have this thing ignite enough to scare the crap out of the pilots and force them to land RIGHT NOW, but gives them time to land. It'll be okay for my story if the plane is destroyed by fire after they land. They just need to be able to land.

Preliminary searching on my part suggests that a weedkiller & sugar bomb could work, maybe tied into a couple of road flares for extra oomph. What I'm not clear on is how to delay the ignition long enough that the bad guy can be sure it'll go off while they're in the air. A smoldering cigarette won't work, because the odor will immediately give it away.

So: improvised incendiary with a 15+ minute fuse. Bonus points for description of what they might see/smell.
 

Cyia

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Road flares + anhydrous ammonia in a contained environment? (I'm thinking of the West, Tx. explosion here.)
 

Mark HJ

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Once upon a time... there were chemical delay fuses, but I don't know if you can get anything like that now, and even if you can, it's probably not going to be just lying around. Rigging something with a mobile phone is probably not something to do in a hurry.

So much depends on exactly what your bad guy has to hand.

Does your bad guy have access to either caustic soda or sulphuric (battery) acid? I seem to recall that those old-time delay fuses often worked by having an acid eat away at something which held a spring-loaded pin. Once the retainer weakens enough, it goes bang. You could create some sort of delay mechanism using acid to corrode a metal - either thin steel or better yet zinc, or you can use caustic soda solution to corrode aluminium. As a bonus, both those reactions generate hydrogen, and in the case of aluminium and caustic soda, the reaction accelerates exponentially and can put out a lot of hydrogen. In both cases the actual timing would be a bit uncertain. There ought to be relatively little odour from either the acid or the alkali mechanism, although it starts getting hot enough there might be a bitter smell in the air, but possibly not out of place with machinery smells.

In terms of a detonator/igniter - if one of the above mechanisms keeps two electrical contacts apart, having them complete a circuit with a loop or coil of wire buried in your weedkiller/sugar mix and powered by a decent lead-acid battery, it ought to get hot enough to do the job. The wires from the battery want to be quite meaty, and then something finer inside the incendiary - the fine wire will melt sooner than the heavier wire, but it wants to be chunky enough to get decently hot before it fails.

I know it's a bit of a cliche, but there doesn't happen to be a microwave oven onboard? Frankly, it has a delay timer and if you have some suitable metal like strips of aluminium foil, they ought to get hot and start sparking once the microwaves fire up, and probably enough to ignite a weedkiller/sugar mix. As a cautionary note, I seem to recall that chlorate (weedkiller) and sugar is a dangerous thing to mix - likely to go off in your face.

As an alternative on the microwave - your bad guy could wire his detonator/igniter into the power for the internal light on the microwave.
 

Al X.

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Simple. Plastic jar filled with vinegar, form a tube filled with baking soda, tightly wrapped, put in jar, put cap on, place in baggage area, then walk away. Any kind of loud pop will be reason for immediate landing.

Or, pour a healthy amount of acid in to the turbine oil reservoir. It would probably take about a half an hour before the bearings are eaten enough to make the engine seize. They will make it back on the other engine.

A guaranteed solution can't be fabbed in 15 minutes. If you happened to have a mechanical timer and large battery, you might wrap a wire around a flare fuse and rig it to the timer.
 

JDlugosz

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Use an actual timer.

Phone? Any gizmo that does timing, such as a sprinkler timer. Look these up or buy one to get details: self-contained, battery operated, scews inline to gargen hoses and operates a high-torque geared motor to close a valve when the time expires. You can stick something through it and it will be crushed, or you can wind dentil floss around the shaft and have it be pulled hard.

BTW I saw a website about serious weapons and delayed explosives made from things that could be bought inside the secure airport.

Here we go:
Recently, Booth launched a year long study he calls "Terminal Cornucopia."

After a year of research, Booth said he discovered that he could make deadly, dangerous weapons out of simple things like Axe Body Spray and metal coffee tumblers.

Booth has built a total of 10 weapons, including what he calls the "Blunder Business Class" -- a small cannon -- and the "Fraggacino" -- a handheld grenade he made using travel coffee cups.​
 

cbenoi1

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> Mitsubishi MU2

Bad choice of airplane to survive in. First the MU2 has a bad reputation. Its laminar flow wings make the plane land at a much higher speed than your run-of-the-mill Pilatus or King Air, so a crash landing is always catastrophic. After 15 mins of flight, the MU2 is probably at FL23 - FL27, which means the cabin is fully pressurized. No way to open the windows to vent off the smoke. That's the deadly thing. It makes the pilots blind because they can't see the instruments, let alone the outside world. Stall and spin are the usual result.

In the end it depends if you want the plane to crash-land or just find the closest airport to divert to.

Here are a few things that would force a diversion after a while and are virtually undetectable during pre-flight inspection:

a) partially plugging the fuel vents with chewing gum. Both engines quit after a few minutes at altitude. It's a long but survivable glide to the nearest strip.

b) breaking / plugging the pressurization probe. Cabin pressurisation starts at about 7000 ft in the air. With the probe plugged, pressurisation is delayed and pilots will start to feel hypoxic above 13,000 ft. They will have no choice than scram down below 10,000 ft and look for an airport.

c) disable the windshield anti-fog system. The windshield will fog up at altitude, forcing the plane to go back down.

d) same as above, but the general heating system. With people freezing at altitude, the way back to much nicer weather is to go down.

e) Disable the pitot tube heat circuit. If the flight goes through clouds on the way to cruise, the speed indication will slowly become wrong and cause an emergency descent.

f) block the inertial separator. Makes the ITT gage go up to dangerous levels when at altitude, causing an emergency descent.

g) remove the succion filter and blow sandy dust into the succion line. Works only with "six packs" instruments. The giros hooked on succion will have their gears degrade over time, the spinning rate will fall and the giros (attitude and HSI) will eventually tumble and die. Losing giros while in IFR is a bona fide emergency.

Hope this helps.

-cb

 
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WeaselFire

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Balloon filled with aviation fuel mixed with soap flakes taken from the crew laundry. Ignition by a candle that will burn down to the right level in about 20 minutes. Quite a simple little napalm blast that will start a fire, write the rest as needed. The old cigarette in a matchbook works well too, as an ignition source.

And if you're afraid of discussions on the internet about how to build bombs causing further world strife and mayhem, you need to unplug everything and hide in a cave. This information was published half a century ago and is freely available.

Jeff
 
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cmhbob

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Continuing with this.

I'm going to handwave a bunch of this, I think. Smoke odor, then a couple of pops, then lots of smoke.

Danny tells the pilot "Smoke in the cabin."

Pilot says, "Get buckled in and get on oxygen. I'll have us on the deck in five minutes."

I've found the MU-2 pilots checklists, which tells me generally what they'd do, but not what everyone would see/hear/feel.

Checklists say
  • Oxygen
  • Interior lights on
  • There's stuff about circuit breakers, etc. if it's thought to be electrical

Then it talks about emergency descent.
Power Levers to FLIGHT IDLE
Condition Levers to TAKEOFF/LAND

That's going to make it relatively quiet, right?

It's also going to be a fairly steep descent, yes? They're going to end up on a highway west of Little Rock. Assuming IFR flight, who's the pilot likely to talking to? Memphis Center, or Little Rock Airport?