An unusual weekend project

[Marc]

Not long ago, I watched with fascination a real competition between French and Americans in the building of a full scale fully functional catapult in Scotland, and told myself that one day I would build such monstrosity myself.

Since it does entail the need for a rather large backyard, in my mind I put it at rest for when I finally get around buying that elusive farm I have been looking to buy, for some years now.

Meanwhile the idea comes up from time to time and I was surprised to discover that the fascination for trebuchet or catapult, is not my exclusive realm, so I thought I share with you this link that among the many available on the net seems to be an in-between the many toy plans available and the real thing.

It is still able to hurl decent size projectiles around without needing to be build with the help of a bulldozer.

http://www.io.com/~beckerdo/other/trebuchet.html

Of course if you are like me and would rather go for the real thing, have the time and the space to spare, have a look at this little beauty: http://www.ripcord.ws/
http://www.stud.ifi.uio.no/~oddharry/blide/vtreb.html

[soundman]

I too saw the big rock chucker documentary, what a hoot.

on a smaler scale a couple of mates of mine built a cross bow using a cortina stabaliser bar????

took both of them all their time to cock it.

using droom sticks for arrows it would punch straight thru 18mm chip board at 20M.

boys will be boys.

[journeyman Mick]

COOL! any chance of a pic and/or plans?:D

Mick

[Marc]

Free
http://www.ripcord.ws/plans/plans.html

Not free:
http://www.redstoneprojects.com/trebuchetstore/trebuchet_plans.html

MOre
http://members.iinet.net.au/~rmine/seemore.html#armedl

And now. . . .. . the peace of resistance.... the real thing:
http://www.asme.org/mechanicaladvantage/December2000/medieval.html

[journeyman Mick]

Sorry Marc, I meant plans for the crossbow. I too saw that documentary (was part of a series from memory "A Passion for History" or something similar). Those boulders hitting the wall were pretty awesome.

Mick

[Dan]

I saw something on TV about trebuchets a couple of weeks ago.
Some bloke (think he was american) decided it might be a good idea to give his missus the flick (so to speak). So they set up a safety net, decked 'er out in all the latest safety gear (she had a helmet), and let fly. She hit the net dead center, no worries, rebounded out of the net and hit the deck. All very embarrassing for everyone involved (and painful for the lady). I think the show was Worlds Greatest Idiots, or something along those lines. Much better to hurl big rocks I think.

[soundman]

ther were never any plans drawn for the crossbow.
It was many years ago and it was very rough.

the stabaliser came drom a MKIII cortina the shaft was a lump of hardwood the string was a bit of wire (probabably handbrake cable)

[journeyman Mick]

Oh well, probably just as well, I've got too many things to do as it is without getting into more trouble.

Mick

[Zed]

mick,

you wanna be careful if your planning to make a cross bow - these things are both excellent toys and very dangerous. the police will be very interested also... even if you make a trebuchet they'lll want to talk to you....

Was it in the upper nsw coast that some kid shot another with a homemade crossbow recently ??? - the force was so great that the bolt went clear though the shot kid. - you wanna be careful here mate - the cops will arrest you so fast that you dont have time to spell arrest...

to make on is very easy I wont describe it here in case one of us gets in trouble - the hardset part of the project would be to get some sort of winding mechanism to wind back the spring steel which gives the cross bow its kick.

FYI - did you know that if you shot a bullet, an arrow and a crossbow bolt through the same sackful of sand the bullet would stop about about 2 or 3 inches inside the sack, the arrow would protrude through the other end and the bolt would be 100m away through the back of the sack - all to do with kinetic energy and wieght of the projectile etc. thats the reason that knights ware very scared of longbowmen and crossbowmen in the middle ages - they would be peirced like sardines in a can... also the reason the french cut off the middle fingers of captured longbow men. this of course gave rise to the one fingered salute that we love and use today. the pommies gave this salute to the french saying - look we have our middle finger are you ready for us mr sardine can ??? This is a true story!

[journeyman Mick]

Okay fellows, I know you're all trying to be responsible but go on, admit it, we all like to play with toys! I've had a few crossbows so I know how much force they can have, the last one I had needed 180lbs pull to cock it. I don't think getting them cocked would be the hardest part, a small trailer boat winch would do it, it's the trigger mechanism that's the hardest part. And yeah Doorstop, I've got one of those PVC "spud guns", I use it as a bird scarer. No one's complained yet (I live in a semi rural area) and I don't fire projectiles out of it (anymore) so I think at worst the police would probably caution me. But the idea of building a contraption that could launch a bowling ball clear into the next paddock or a broomstick further still is certainly intrigueing.:)

Mick

[Marc]

I agree about the being responsible guys, but in all honesty there are no laws against building trebuchet much less if they are designed to throw tennis balls. Perhaps a full scale one would need permission to operate in a public place... mm... don't think you will do that anytime soon, and plese dont attempt to swing any cats either.

As for cross bows, that is another matter, they are illegal in NSW yet use to be perfectly legal in Queensland where we use to hunt pigs with them.

Since I haven't been hunting for a while and favor a 308 over the crossbow particularly for those angry mobster in Queensland (the four legged hairy variety that is), I don't know if that has changed.

Probably has, given the mass histeria over guns and knifes and soon over nail clippers . . . . . I wonder if I need a license for that nail gun I am planning to purchase neeee only kidding.

Thank you all for the info over nail guns by the way.
Turulu

PS
the observation on ballistic effects on a sack of sand are correct,
but please don't assume now that a bullet is less dangerous than a crossbow bolt. Bodies are not made out of sand and what kills is the hidraulic effect of the impact of a small mass at high velocity.

Much more interesting is to observe the effect of different projectiles on a plastic container full of colored water, or alternatively a ripe water melon.

[AlexS]

Marc, you're right about the hydraulic effects of munitions I remember my first army firepower demo when they showed the effects of 7.62 mm on various things...reinforced concrete, hardwood, sandbags, full & empty 4 gallon drums etc. Several layers of wet sandbags hadthe best stopping power, but a drum of water just exploded.

The last demo was the most impressive..."Watch now the destructive power of a 6" bolt fired from a crossbow." Way over on a hill about half a mile away a huge eucalypt disappeared in a cloud of smoke & splinters.

I'm sure the instructers wouldn't have played tricks with plastic explosive would they?