Catapolt

[AndyR]

The NOVA show used the skills of Virgina Military Institue and some contribution from the Timber Framers Guild. Last fall I was happy to see flaming pumpkins flying into the sunset care of VMI's "mini" trebuchet (only about a 20 foot arm on that one).
There is a place in the next town where someone is building the mother of all trebuchets - the wheels are about 6 feet in diameter and the main pivot is about 30 feet off the ground. I think he will need a 70 to 80 foot arm and a few tons of counterweight. Ther is a TFG <A target="_blank" HREF=http://store.yahoo.com/tfguild/bacisoftimfr.html> publication</A> that may have a few pictures. I am off to a barn raising but will try to scan in some of my pics. when I can.

 

[Golfgar4]

You got it!! /w3tcompact/icons/smile.gif

 

[GlennT]

There's a couple of books listed in www.amazon.com. I've read one of them: Catapult: Harry and I Build a Siege Weapon, by Jim Paul It's kind of interesting but wouldn't be very helpful in building one. The other is: Build a Catapult in Your Backyard, by Bill Wilson and it costs $8.00. Nova had a program or two about building catapults and using them to knock down masonry walls. I must say, thought, that I'm glad I don't have you for a neighbor.

 

[LTEnterprises]

I'm not gonna shoot it AT my neighbors. I just think the thoughts going through their minds when they see furniture flying 100 yards or so on MY property will be very readable on their faces. I will get a belly laugh when I start hearin comments I am gonna build a small one for fruits and vegetables to practice with. Then I am going to build a big one..I think I have found a source for telephone poles. The physics is fun. for instance the Ideal boom ratio is 4.5 to 5/1.
the CW ratio is 100 to 1. for every 1 pound of projectile the optimum weight on the short end needs to be 100 pounds. I guess the designers want to "HURL" fantastically !!

 

[RobertN]

Patrick, I agree... I was going from memory(inaccurate memory)(and terrible spelling; I just looked at my post again!). I know with my basic 72lb compound bow, I can easily place on a 100 yard target, when I'm in pratice. The long bow should easily place an arrow that far, and beyond.

This is a fun thread; My son and I are thinking of building a smaller catapult for a second grade science fair/w3tcompact/icons/grin.gif

 

[RobertN]

That is it! Yes, a dead cow in your water supply could really mess things up!

 

[kcbarnes]

Maybe we need to get a group together and build a TBN trebuchet.

 

[patrickg]

Neat science project, Bob. I've seen miniature working models of various siege engines (is that generic for catapult and balistas and ...?) I made one in later grade school that used a weight and gravity for propulsion with a swing arm. It lobbed small stones at a high angle of fire, suitable for firing near to the target and having the projectile come down at a steep angle. Good for firing over a wall and falling down on the folks inside, like a mortar.

Second grade... Wow, that brings back memories, second grade was three of the best years of my childhood! Just kidding. I think I was in the second grade when I was using the football field for my long range archery. Can you imagine a time when parents and neighbors would be just fine with a 2nd grader out shooting a bow over 100 yds with no supervision. Times they are a changing... actually that shouldn't be a present participle but some past tense like past perfect, as times have changed.

We bought a house in a different school district across town and moved from that location (archery site/football field) at conclusion of the third grade so if my memory is flawed about the 2nd grade it could have been no later than the 3rd grade.

The annual San Diego State University Haloween riots see a lot of 3 man catapult action. Two guys act as the stock of the slingshot and a third stretches the surgical rubber tube powered water baloon launcher. They get some amazing ranges and some "fire teams" exhibit real good accuracy as well.

Patrick

 

[MJB]

I remember watching the PBS show mentioned earlier. The archer they had on the show was firing arrows over 300 yards with his longbow./w3tcompact/icons/shocked.gif They also had him fire one point-blank at a suit of armor. The arrow punched clean through the armor and the fletchings on the arrow just stopped it from falling out the back.

 

[LTEnterprises]

I believe I am gonna ues steel for the throwing arm on my treb. I believe an H beam is the strongest steel beam structure. problem is that I want to hurl 100 lbs so that would mean 10,000 lbs counterweight ??!! I saw a video of some guys hurlin dishwashers and ranges and I believe that their CW was 3,000. any answers by more knowlegable than I ??
this is gonna be fun !!