Like the rest of this site, building a machine that can Like the rest of this site, building a machine that can throw playing cards is one of those geeky projects that really does’nt better the world one single bit. Its yet another technical challenge posed by a bunch of guys whom never grew up. Where do I find these people? The Impetus Many
people have seen the episode of the Discovery Channel’s Mythbusters
where they tackle the myth of the “Killer Card”. The
myth goes that a skilled person could fatally wound someone with
an ordinary playing card. Here are of the show notes: throw playing cards is one of those geeky projects that really does’nt better the world one single bit. Its yet another technical challenge posed by a bunch of guys whom never grew up. Where do I find these people? The Impetus Many
people have seen the episode of the Discovery Channel’s Mythbusters
where they tackle the myth of the “Killer Card”. The
myth goes that a skilled person could fatally wound someone with
an ordinary playing card. Here are of the show notes: |
The
obligatory “Don’t try this at home” opening. |
|
The
prototype. Looks like a router with two rubber wheels. |
Ouch.
Most of these were actually hand thrown. |
As with
any projectile –its penetrating power on impact relies on
both its mass and velocity. This playing card weighs in at 1.6grams…. |
… and
was clocked at 150mph! |
The Challenge By the conclusion of the show it becomes quite clear that killing someone with a playing card is really far fetched, but it was just enough to self-challenge ourselves. The goal was to hurl playing cards 45feet into a small trashcan flipped on its side. I won’t get into the details of the bet but one part of being the loser is taking A FULL 52 card deck in the back from the winner’s machine! The Feasibility Test
Theres a little physics to it.... Four
factors influence the flight of the playing card, speed, rotation,
gravity and air. Just for laziness sake - I'll Since
the bullet spins when it leaves the barrel because of the rifling,
it has angular momentum. When
these irregularities are started the bullet will start to wobble
and will cause the bullet/card to vary from its intended course.When
the bullet or a plying card is affected by air resistance its linear
momentum will also be When the linear momentum decreases with constant angular momentum the card will yaw which causes the bullet to become unstable and not fly to the intended target. These factors contribute to the how the bullet will fly through the air to the intended target. Recent tests with the last version of the card shooter proves that these factors become significant at 40+ feet.
Development
of Machine #1
Play
the first test shot video |
only
write about the crutial factors...
“yawing” the
bullet will tumble and fail to connect with its intended target. If a
bullet spins too fast, it causes the irregularities of the weight distribution
of the bullet to be exaggerated. Rotation is crucial. Without it a throw
on playing card would flutter and tumble like a falling leaf, because
the aerodynamic forces aren't perfectly centered. The lift is often slightly
stronger on the forward half of the card, and so that half usually rises/falls
causing it to flip over.
affected.
Linear momentum of is measured by the cards/bullets velocity and
the mass of the projective. The velocity will decrease as the distance
traveled increases. Air resistance and drag, created by a playing
card contribute to a decrease in linear velocity of the bullet. You
can see that while linear momentum decreases and the angular momentum
stays constant, a target farther away will become harder to hit. 
