Outrageous Experiments

Myth Database – Improvising a Weapon From Junk

posted: 02/09/17
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MYTH: Can you improvise an effective weapon out of junkyard scrap and heads of cabbage?

PLAUSIBLE

This myth derives from the A-Team TV series, in which Hannibal, Murdock, Face and B.A. would frequently improvise weapons from scrap, including one episode in which they successfully fought off bad guys with a hastily assembled cabbage cannon.

In this case, the challenge was build a weapon using parts found in a well-stocked junkyard or scavenged from an earlier build in two days. To be judged successful, the weapon would have to take out six bad guys in three minutes using nothing but cabbage as ammunition. The candidates would be allowed access to all the tools in the shop, as well as "consumables" (wood, nuts and bolts, tape, etc.), but the bulk of their machine would have to be sourced from the junkyard.

Team Blue (Tamara, Hackett and Jon) first considered building an air cannon, but decided that the cabbage would shred instead of launch. They settled on a repeating crossbow cabbage launcher, using a truck's leaf springs as the arms, square tubing for the rails, and wire cable as the drawstring. In the scrapyard they also found an old winch to wind up and then release, catapulting their cabbages.

Team Red (Brian, Allen and Martin) chose an air cannon, electing to core the cabbages into aerodynamic bullets. In the yard they were able to source their barrel (plumbing pipe), firing tank, ball valve, air tank and compressor -- and even a cement mixer that would allow them to turn the cannon on all its axes, improving aim. They also found a microwave.

How did a microwave fit into the Red Team's air cannon? The cannon needed its valves to turn on and off, preferably automatically so that the team only had to worry about aiming and shooting. Microwave ovens contain a built-in timer, as well as circuitry that can turn things on and off. Allen gutted the microwave, removing the magnetron (the part of the microwave that actually makes microwaves) and replacing it with a solenoid valve from a previous build.

In the end, here's how the Red Team's air cannon worked: a junkyard compressor pumped air into two reservoir tanks controlled by rapid release ball valves. To fire, Allen's microwave computer triggered a release of the pressurized air to fire a cabbage core bullet, then automatically refilled the tank, ready to fire again. The cement mixer served as a targeting mechanism, allowing for both elevation and left-and-right control. After just one day, the team tested their cannon and it fired successfully.

Here's how the Blue Team's crossbow worked: The cabbage sat in the sled, which was attached to a quick release, which was attached to the winch. After winding the winch as far back as possible, the team would pull the safety pin, sending the cabbage flying.

However, after one day, the Blue Team's crossbow was less than effective. With its air cannon finished, the Red Team decided to pitch in to help the Blue Team. After reviewing the crossbow's design, they realized that the leaf springs were permanently deforming when bent a certain way. By flipping them, the springs could be bent back without losing their shape. And by adding two more springs, for a total of three leaf springs per side, the team was able to increase the crossbow's power.

On test day, the challenge was to take out as many of the six bad guys as possible in just three minutes. Brian Labrie, world record holder for pumpkin chunking and owner of American Chunker, served as guest judge.

The Blue Team's crossbow was able to hit four bad guys in three minutes, although reload time was slow, lethality was "less than ideal," and the Red Team had had to help out.

The Red Team's air cannon took out five targets with "deadly accuracy" and lethality -- but given that it was able to do so in part because of the solenoid valve, an expensive part unlikely to be found in a junkyard, the myth was deemed only plausible.

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