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Code Name: Janus




Team Urban Siege has a new winter project. It seems that we cannot go too long without building a new machine, and this winter is no exception. The design? A Floating Axle King Arthur/Floating Axel Whipper trebuchet. That's right, we are finally going to try out a whipper design. But this trebuchet is also intended to help us try some small changes we are considering making to Medieval Postal Service, hence the King Arthur mode. Actually, there are a number of critical points that this new machine is intended to address:





2009 WCPC Post-Mortum




So it has been nearly a month since we returned from Delaware and the World Championships of Punkin' Chunkin'. It is time to really condense down what happened.





Medieval Postal Service Set up and Ready to Roll




Well we finished setting up Medieval Postal Service today with fairly little incident. Really the only issue was that it took a while for us to get inspected, as the inspector likely forgot our request with all the other stuff he was undoubtably having to deal with. No big deal, we got inspected and got our first shot off around 4:15 PM (though we were ready to start firing ops around 2:30). A decent shot, but the one 25 minutes after it was even better, certainly a 1000+ foot shot. We are expecting stiff competition this year, as several teams from last year have made massive improvements to their machines, First in Fright and Hokie Hurler being among them. Shenanigans II should also be right in the mix, assuming they can get off reliable shots. They are there and set up, but we have yet to see John or Tom. Pumpkin Hammer is on site, unfortunately firing as a standard HCW this year due to some major problems that cropped up during their testing this fall. Yankee Siege looks pretty strong, and Merlin showed up late in the afternoon. This year Chris Gerow also brought the 3-time World Champion (albeit a few years removed) King Arthur, which historically shot right around the distances we are probably looking at. Like I said, it should be and interesting competition.





Team Urban Siege Reaches Delaware




Team Urban Siege has made it down to Delaware and is beginning to set up Medieval Postal Service. We were able to move right in to our pit as soon as we arrived around 3:20 after leaving Rochester at 7:20AM. This is despite the large amount of rain that had fallen on the field over the last week or so, prompting remarking of the pit locations at least once. Still, all was fairly dry once we got on-site today. Tomorrow we plan to finish setup, as we were only able to get the base put together before we ran out of light. Plus, we were tired after almost 7.5 hours of driving and an early morning to boot.





Medieval Postal Service is Ready for the Chunk!




Well, Medieval Postal Service is done with testing for 2009. We had a fairly successful testing period, despite the constant rain which washed out several days that could have been used to test even further. Nevertheless, the machine is firing at full capacity, and so far is not trying to destroy itself on each shot like last year. This in itself is good news. This weekend we will be packing up the machine for transportation to Delaware. The plan is to leave early Wednesday morning so that we get down to the field around 3 or 4 PM, and get our pit assignment and a few other little details sorted out before we begin to set up on Thursday. This year we ought to be able to shoot some test shots on Thursday, which will be good since we will be able to make sure we are in shape to compete starting Friday.





Medieval Postal Service Prepping for the Chunk




We have gotten Medieval Postal Service set up and firing again in preparation for the 2009 World Championships of Punkin' Chunkin'. This past summer was spent doing a lot of rebuilding, modifying, and redesigning. After all this work, we took the machine down to our range on September 19, and began set-up. The weekend of the 26th was mostly a washout, and we got very little accomplished, but this past weekend we finished up and actually took some shots with a little counterweight and our 4-pound medicine ball, just to make sure that the modifications all work properly. They appear to be performing as well, and the three low-power shots we took were all very impressive. One shot actually nailed a tree dead center and came shooting back out of the treeline, which was an amusing moment.





Straightening MPS's Tracks




This past Saturday we spent some time at Great Lakes Pressed Steel straightening the tracks to Medieval Postal Service. Both tracks had a bow in them from the original welding process last fall, and so we had to be very careful when clamping the carriages to the main axle. The tracks both bowed inward along their length such that the center of the tracks was about 1.5" tighter than at the ends. We had to adjust the carriage spacing so that the wheels were not too tight in the center, but still were not in danger of falling off the tracks. This took quite a bit of time to get right, and was an issue we were not happy about. We lived with it for 2008, luckily without too much trouble, but this issue did not help matters when we misfired our last shot at Delaware.





MPS Plans for 2009




We had a successful 2008 World Championships of Punkin' Chunkin', despite not meeting any of our goals for 2008: finish 4th and break 1000 feet. Really, these were hand-in-hand, as 1000 feet would have easily taken 4th place, as we figured. We failed, not due to the trebuchet not being as powerful as imagined, but due top a lack of testing. We actually think we have more power than initially imagined. We had originally thought that setting up the trebuchet for the first time in September would only take one to two weekends, but it ended up being more like 4-5 due to machining errors (some design-induced) and other little things that added up time-wise. Still, we lucked out in Delaware and got off 2 solid low-power competition shots. Now to get up to the full power level: 600 pounds of counterweight, which is what we designed for nearly one year ago. With the full counterweight, the arm should now stall correctly thanks to a more favorable mass ratio. In turn, we will be able to use a longer sling, and capture much more of the energy available into the throw.





Summer-Fall 2008




Most of the Summer and Fall of 2008 was spent building Medieval Postal Service. After the frame design was completed in late June, the first pieces, the bases naturally, were cut in early July. Throughout the course of the next month we would purchase wood (picking carefully through the pile at Home Depot, getting roughly 20 boards at a time), and cut more pieces. Come early August, most of the wood frame pieces were cut and the sub-assemblies built. However, the arm, hanger, tracks, carriages, and other assorted components were still being designed. And that process was stalled even further when in mid-August Matt left town for close to three weeks due to the impending death of a family member. Jason was also gone on vacation for close to two weeks during this time, and so not much got accomplished on Medieval Postal Service during the month of August.





We Went to Delaware...




Long time, no update. We did in fact pack up Medieval Postal Service and head down to compete at the 2008 World Championships of Punkin' Chunkin'. We did not get the chance to launch any 8+ pound projectiles before heading down, and so had to wing it for the competition. Despite a few design flaws that reared their head (some of which we already knew about), we managed to place 7th, shooting a solid 686.79 feet on the second day of competition. Oh, and what type of trebuchet was this mystery machine? The most efficient style developed to date, a Floating Arm King Arthur. Our longest shot was with only 400 pounds of counterweight, and we designed for 600 pounds. Once we get the design flaws worked out this winter and spring, we are going to try to break 1200 feet next year. Originally we were trying for 1000, but based on what we have seen from this machine so far, 1200 is also very possible, and perhaps even more.







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Use "common sense" when operating trebuchets and catapults. Even little ones can be dangerous. Do not place anything you are not willing to lose in the plane of the arm rotation (this includes yourself, body parts, car windshields, cameras, etc). These catapults and trebuchets are capable of throwing just as far backwards as forwards, and the use of a backstop of some sort is recommended, though the use of one does not make the region behind it safe.

Also, just because the throw got away safely downrange does not mean the end of the danger. The arm is likely still swinging wildly along with the counterweight, and there is a sling whipping around. One thing many people fail to take into account is this sling; some people put a metal ring on the slip end of the sling and this ring can HURT when whipping around!

Have fun hurling, but please KEEP IT SAFE!!!