These military Frisbees are six to ten feet in diameter, made of concrete. A center pin on the launcher spins them up to several hundred rpm before launch. A catapult then flips them side-armed towards the enemy. A spinning disk travels slowly, but on a flat trajectory, giving the panicked enemy only a thin profile to shoot at. When it finally hits the target—or anything—it immediately explodes like an overstressed flywheel, shooting a spray of lethal fragments horizontally over a wide area.

Notes on construction: The energy of detonation is just the kinetic energy stored in the rapidly rotating concrete. When it impacts, the entire thing breaks up in an instant, with the fractured debris traveling outwards on tangents at the same velocity they possessed while spinning. Before launch, the disk is spun up using a drive socket in a steel plate integral with the disk. As the plate resembles a regular Frisbee, and is often later used as a toy by local orphans, suitable educational messages may be engraved upon it. Like “A Gift from the Children of the United States to the Children of [insert name of latest enemy here].”
-- ldischler, Jun 05 2004

(?) this idea referenced on LiveScience http://www.livescie...07_death_disks.html
[theircompetitor, Sep 08 2006]

Original death frisbee aticle http://www.technove...ews.asp?NewsNum=733
Nobody reads the credits... [ChiefTechnovelgist, Sep 08 2006]

(?) USN Giant Frisbees http://www.defenset...rchives/001472.html
The navy tried giant six-foot frisbees in the early 1990's. [ChiefTechnovelgist, Sep 08 2006]

[ldischler] to truly americanise the weapon it would need to be made of some radioactive or enduringly carcinogenic substance, it would have to exhibit a preference for heading towards British and other allied assets, wedding parties, old people and children , and it would need to come from some conglomerate (BungCo?)that overcharged by an order of magnitude and then paid some of their superprofits back to Republican congressmen who approved the program in the first place.
-- ConsulFlaminicus, Jun 05 2004


All good points [Flaminicus], but better applied to the Giant Boomerang, a concrete weapon with a twenty-foot wingspan.
-- ldischler, Jun 05 2004


I voted against it because of the last sentence.
-- dentworth, Jun 05 2004


This would lead to Ultimate War.
-- hippo, Jun 05 2004


Used as a toy? How?
-- bristolz, Jun 05 2004


Flywheels can store ungodly amounts of energy. I'm really anti-war but as an engineer, this would be a devestating weapon.
-- 5th Earth, Jun 05 2004


Do you mean 'the shattered fragments are often later used as a toy...' ?
b/c I'm not sure how much fun a giant concrete disk would be to play with.
+ anyway, for being more interesting than bombs, and harder to decriminalise.

chocolate chip muffin...... (okay, not quite that good)
-- blueturtle, Jun 05 2004


I worked on a project where the main idea was to give a projectile extra energy by spinning it up to high RPM. It was for concrete penetrating anchors in construction and it was abandoned because the projectile would have blown up any wall under 6 ft. I'm not sure about the frisbee, but a fast spinning rod could be devastating.
-- kbecker, Jun 06 2004


Seems to me the defense against this would be fairly simple. Some really big wind generating fans should do it.
-- waugsqueke, Jun 06 2004


It's not the giant concrete frisbee that's used as a toy, it's the small metal drive plate embedded in it which is released when the concrete shatters.

I don't really approve of weapons, but I love spinning things... so I think I will... bun. Or fishbone.... No, bun.
-- spacemoggy, Jun 06 2004


First off, this is cool. Secondly, what if both armies had one and fired them both at each other at the same time?
-- swimr, Jun 06 2004


The engine required to get this thing spining would be mosterous. Maybe the structures that shoot these things could be kept under ground shooting them at a slight angle out of reinforced concrete slots.

Why not put hollow pockets filled with metal balls in it. Concrete breaks in uneven pieces. some may be the size of a basketball, while most will be pea sized with very little force behind it.
-- xcpostman, Jun 06 2004


//The engine required to get this thing spining would be monsterous//
Why? It's a flywheel, less input should just equal more time.
-- 2 fries shy of a happy meal, Jun 07 2004


If it were hollow and mounted vertically you could use a lot of hamsters
-- brewer, Jun 07 2004


The enemy would just employ a really big dog to catch it!
-- MikeOliver, Jun 07 2004


I'm a bit surprised that no one has compared this to a giant clay pigeon thrower and remarked about the relative ease that skeet shooters have in knocking down the flat trajectory disks.
-- jurist, Jun 07 2004


[tabs], sorry, i didn't see your anno there...
How about if they get the Nike stick man?
-- MikeOliver, Jun 07 2004


I'm wondering if a normal rifle would shatter this thing. Your bullet breaks off a little piece of concrete, which causes an imbalance and a crack, combining that with the low tensile strength of concrete...
-- Worldgineer, Jun 08 2004


It's called flak.
-- WordUp, Jun 11 2004


ldischler, please note you're being quoted as one of them "out of the box thinkers" on Halfbakery.com -- see link.
-- theircompetitor, Sep 08 2006


BTW, Larry Niven wrote a story in his Magic Goes Away series about a sorceror who put a spell on a spinning metal disk that would increase its rate of rotation almost indefinitely. Anyone trying to use a sword on the wizard would strike the disk, releasing all of the kinetic energy. Great weapon.
-- ChiefTechnovelgist, Sep 08 2006


Mwahahahah, it's diabolical!
-- quantum_flux, Nov 18 2007


[quantum_flux] that give's me an idea. A huge Diablo (2 frisbees with an axle) that you can just let go to trundle across the battlefield and wreak hazoc.
-- marklar, Nov 18 2007


When he was younger (and stupider) my old man and his mates made something a bit similar (or at least interesting).

They made a steel plate, slit it to make a crude propellor (maybe 16 inches across, 1/2 inch plate - guesswork based on hand gestures). He would never describe the launch mechanism suffice to say that it spun the plate up very fast. From constant needling him, I gather it was spring or elastic, and used a ratchett bearing from a high speed air drill - but that could be a red herring <sneaky bugger that he is>.

When a catch was released, it would take off skywards, rather enthusiatsically. Needless to say, this was on a farm several miles from roads, houses, etc.

Apparently it was a bit errattic in flight, and was worse when it hit the ground, and there was some kind of incident one day, I think someone's car was essentially destroyed. Or something like that.

So they stopped playing with it.

From what I gather this thing would reach heights of several hundred yards.

I plan to make one myself one day.
-- Custardguts, Nov 18 2007


This thing would be great for debulking massed zombie hordes outside your refuge. Plus one could get it up to speed using a bicycle and a series of gears. You would want to be able to make new ones with materials on hand since you might not be resupplied - perhaps wheels from cars?
-- bungston, Nov 19 2007


Just a small amount of flak in no-man's land would effectively eliminate it.
-- RayfordSteele, Aug 27 2009



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