Been away almost a week... What I did to take my mind off politics...

While I hadn't exactly planned for a "cooling off", I spent since Wed, away from all news. Was in rural Delaware, throwing vegatation long distances... An event otherwise known as the "world championship of Punkin Chunkin", where a crowd of fairly strange people make even stranger machines, in attempts to toss the pumpkins that missed jack-o-lantern duty, as far as possible.

This year the team had two machines entered, Mista Ballista, a "modern" adaptation of the ancient greek rock throwing machine. Think crossbow on steroids, lots of steroids... The other was the previously retired "pumpkin putter" a human powered centrifugal machine, dragged out of its rest, to help make up the three of a type needed to create a new class.

The ballista is made to the sizing formula's of ancient machines, but out of modern materials - steel instead of wood, with composite arms, and plastic rope. We use hydraulics to wind up the rope "springs" and to lift it to firing position, with an electric winch to haul the bowstring back. It has an arm span of 25 feet, a pull back of 20 feet. The bundles of rope that power it, are 7 feet tall, almost a foot in diameter, and contain 1,200 feet of 3/4" rope between them. The bowstring draw is currently just shy of 4,000 lb, but was designed to eventually hit 7,000 lb. It weighs (including its custom trailer) about 7,500 lb. It is 99.9% post consumer recycled material (IE: all of the steel with one exception, came from scrapyards) We figure that including its support gear (like the generator, and hydraulic pumping cart) that it cost us less than $0.50/lb. (we spent more for the build night pizza than we did on the machine)

The putter is a "davids sling" sort of device. The "engine" (our best one answers to Rodger) pedals a bicyle. This (thru 35 feet of scrounged bike chain) drives an 8 foot arm, that has the pumpkin out at the end. (another 8 foot pipe has a counterweight system). When the rider is flat out (tips moving more than 45mph) you pull the trigger cord, and when the arm is in the right place, it trips a pair of vice grips, that releases the strap holding the veg to the arm and the gourd flies, hopefully forwards.

The weather started out miserable, and ended up great. Thursday, we had to assemble the machines, in 50 degree, heavy rain, but things warmed up, and dried out, such that Sunday turned into t-shirt weather.

We didn't have the Ballista fully assembled in time for the friday competition shot (we forgot to pack an all-important pulley, and I had to improvise one), and the chain on the putter fell off, leaving us with a minimal throw. During testing that afternoon, we managed to pull out the splices in the ballista's new high tech bowstring, and we inadvertantly made a test shot, the only shot it would make that day. (it pulled out at only 500 lbs of pull, but the shot almost equalled the machines previous best)

That night we made up a stronger splice in the bowstring. We got to the field, and wound up the ballista's rope springs tighter. I fiddled with the chain on the putter, and got it to stay on the gears.

The new stronger bowstring splices, made it to 1,700 lbs of pull before giving way, this time during the competition shot (each machine gets one measured shot for each of the 3 days of competition, along with several hours of "free-for-all", shoot as much as you want but no shot is going to be measured) Even tho it was at half of last years best power, we got on the board with a shot 50 feet better than last years best. Put us in third, with a 350 foot shot (a distant third, second place was just over 1,000 feet, and first place set a class record at 1,500 feet). The gear tuning helped, and with our backup engine (kevin) at the pedals, managed 132 feet, which put us first in the class (the putters best ever shot was 144 feet).

Rodger went for an "absurd" set of splices, to fix the bowstring. I tweaked the putters gearing some more, and we actually got in some test shots with the putter during the free-for-all. The bowstring didn't get fixed in time to shoot that day.... But we did see a great aurora display that night...

Sunday, the last of competition. We got out the heavy duty winding gear (hydraulic) and put some real twist into the bundles, and put the new bowstring on. We decided that our sturdiest remaining pumpkin should go to the putter, to try to hold onto first.

The pullback on the ballista hit 4,000 lb. But the pumpkin didn't survive the launch, (rules say must leave the machine intact) and even tho the majority of the pumpkin landed over 500 feet away, the shot didn't count. Off to the putter - This time with the primary engine in place, and our best ammo in the pouch. Rodger practically yanked the bike from its moorings, and managed a 176' foot shot. Good, because on of the other teams that was having problems with their release got it working, and chunked 160 feet. (the third team tossed their pumpkin backwards, toward the spectators)

I did say hopefully forward -- the second place torsion machine in the next space to the left, had a part break during a practice throw, and their pumpkin went straight up, likely more than 700 feet. It landed on our trailer deck, spraying pumpkin guts all over...

With a good bowstring, we then tried a bunch of test shots with the ballista, untill we managed to throw a small but critical part (of course it was something custom machined, and no we didn't have any spares) out into the field, ending our test/fun time for this years event. While we didn't get official measurements, the "unofficial" distances were touching 600 feet.

The putter got its name for its short range, and the torsion machines (new class last year) are only middle of the pack as far as distance goes. The trebuchet's (falling weight) managed a new record of almost 1,400 feet, the catapults (any kind of spring except twisted rope) broke last years record, with over 2,100 feet. The not human-powered centripetal machines managed 2,400 a slight gain from last year. It was a good, but not record year for the air cannons, with the winning shot a touch over 4,100 feet.

There were a lot of kids (under 11, and 11-17) machines entered, and they were posting distances that impressed.

We left the event Sunday night with two trophies, one first, one third. We didn't leave with the machines. The truck that had the job of towing the machine back had a brake line burst (rust and old age), luckily while moving slowly. We left it until morning, and a local dealer fixed it. I got home at 1am...

We have a long to-do list for the upcoming year...

see www.siege-engine.com for picturs of the machines...

We have a similar contest in January here - fruit cake, though, and weight limits on the machines.

Maybe I can drag Mr. Pcat away from his battle 'bot to do the fruit cake sling this year. I convinced him to do the Kinetics race with me.... (amphibious boat race...)

Pcat

Friends of the Flatmo's, who have been running in the Arcata event for years. Been contemplating entering the new one in Baltimore. (as much because I thin the sponsoring orginization is great, its the american visionary art museum)

Got into pumpkin tossing becase the 2001 championships was declared a Junkyard Wars alumnii reunion.