If you were gonna launch a Fruitcake...

Using a medieval ballistics device, how would you do it?

2 years ago I built this trebuchet For the Manitou Springs Fruitcake Toss

It was disassembled and forgotten. Now it sits on my garage floor awaiting a rebuild. While examining the bits I had 2 thoughts. 1. Its cold, I am going back inside. 2 Ya know, the GRM board has several engineers, including a ballistics specialist, and a lovely collection of miscreants. I bet they could help.

The arm is 9 ft 5 1/2 inches. The pivot is 2 ft 8 inches from the basket. The basket is large enough for anything, but the fruitcake will weigh less than a pound. I am bound by these Rules I have about two weeks, almost no budget and good access to scrap lumber.

What have ya got? Thanks for your time.

I bet I'm not the only one thinking sabot and pneumatic canon

http://www.youtube.com/watch?v=yHfejwdrMVQ

How effective was your trebuchet?

A Catapult would be mighty cool, if you could knock one up in two weeks. Also, according to those rules, the cake has to weigh either 2 or 4 pounds.

Yeah, the weight rules are lightly enforced. But lets say 2 lbs

We got a single non-measured distance of about 300 ft, but the money shot had us at about 90 ft.

from a similar trebuchet building contest in high school, i remember the hardest part was consistency in the departure angle. the rest is all just simple mechanics (increase weight, move fulcrum closer to weight, etc.) seems your results would indicate a similar inconsistency.

we did manage to smash a glass marble against the concrete wall the opposite length of the gym with just a soda can for weight. that was fun

i am jealous of the awesomeness of your town.

The 4th Challenge Event?

I had visions of a bunch of Chair Force guys using a mobile home as a drop ballast against a pivot board...

How do you get the fruitcakes to stop squirming and yelling for help long enough to load them onto the Trebuchet?

Duct Tape.

Rum, if you read the other threads...

I keep thinking of that infamous Monty Python catapult scene.

Pichez la Vache!! Pichez la Vache!!

I believe if you have the pivot point able to slide fore and aft it will increase the efficiency (fore and aft forces are transmitted to the projectile rather than the ground).

aircooled wrote: I believe if you have the pivot point able to slide fore and aft it will increase the efficiency (fore and aft forces are transmitted to the projectile rather than the ground).

In general, the more you can make the weight move strait down, the more efficient your trebuchet will be.

Putting the weight on a pivot makes a big difference. Putting the weight farther down from the pivot helps a lot too (more than you'd expect).

Setting up a trebuchet like what aircooled said is incredible efficient. Make the weight fall straight down in a channel, and have the fulcrum slide along a level platform.

Snowdoggie wrote: I keep thinking of that infamous Monty Python catapult scene. Pichez la Vache!! Pichez la Vache!!

Run away, run away

Salanis wrote:

aircooled wrote: I believe if you have the pivot point able to slide fore and aft it will increase the efficiency (fore and aft forces are transmitted to the projectile rather than the ground).

In general, the more you can make the weight move strait down, the more efficient your trebuchet will be. Putting the weight on a pivot makes a big difference. Putting the weight farther down from the pivot helps a lot too (more than you'd expect). Setting up a trebuchet like what aircooled said is incredible efficient. Make the weight fall straight down in a channel, and have the fulcrum slide along a level platform.

hmm..... large weight falls straight down channel, pulley system to convert to a high speed launching ramp at the ideal angle. this addresses the biggest variable we had which was the release angle of the trebuchet "sling" like i said above.

Dog, that's awesome! I wish I lived in CO!!

OK, so there's a distance limitation. 260' sounds pretty attainable.

But I note (with eagerness) that there is apparantly no height limitation!

I'm thinking you need to shoot for the moon with a landing within 260'.

SVreX wrote: Dog, that's awesome! I wish I lived in CO!! OK, so there's a distance limitation. 260' sounds pretty attainable. But I note (with eagerness) that there is apparantly no height limitation! I'm thinking you need to shoot for the moon with a landing within 260'.

ooooOOOOOOoooooo! big splat!

C'mon, let's get real here