Having been home...

Having been home now for a week or two I have been reflecting on the experience at Punkin Chunkin. First, it was a fun event. I know that I wasn't very enthusiastic during the event and those feelings still stand, but having done it it was fun. Second, it hardly seems worth it. With our greatest launch of 874 ft. it hardly seems worth all of the effort to walk away in 13th place. We might be back if we can get some longer distances. I have already sent out an E-mail to our fab guys to start the dialogue for creating some new parts which should, 1. make the machine more able to handle greater weight and 2. make the arm about half the weight.

Just an aside, I just found that our slow motion mini trebuchet video on Youtube is linked to on the Wikipedia page for trebuchets. That's pretty cool.

Personal best

Our third and final shot came in at 846.60 feet. That's our best with the machine and would have won LOPL. The trajectory was still a little low but getting much better, finally.

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2000 feet

Yankee Siege hit the 2000 foot mark yesterday, a new record. Word is that the owners have said that due to the cost of coming here each year, they were retiring from P.C. once they hit 2000. That's it for them, but it does mean that next year will be wide open for a new treb champ, first time in 6 years.

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Whoops!

We broke our pouch while testing. We'll come up with something.


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Second launch

For our second launch we shortened the sling by about three feet. Just that change got us to 774 which is our best shot ever but not good enough. The trajectory was high and the sling length was still too high. We are adding 220 lbs and taking an additional 2 feet off of the sling. We are hoping that those changes will get us above the 800 mark.

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First launch

Our first launch was a measly 700 ft with 1500 lbs. It looked like a low trajectory, though. I'm voting for dialing the finger back to try and gain a higher trajectory.

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Really!

Things were so slow today due to a new spotter crew that they stopped the launchings two machines before us. That means that we shoot second tomorrow morning at 7:30 in the morning.


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Not too much fun

So far, this thing is moving at a snails pace. They are losing every shot from the air cannons and so it takes about 20 minutes between shots. We started at about 9:40 and we are about half way through. The other teams can't fire right now and it's very windy (read cold). This is neither enjoyable nor interesting so far. Maybe tomorrow when it's about ten degrees warmer and about 10 miles less wind it'll be fun.


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Launch day

Launch day is here. Setup didn't go as planned so we weren't ready to go with a test launch. That means our first shot in Delaware will be measured. It's definitley not ideal bit that's why there are 3 days.


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First day build

Our first build day went well. We have plenty of time tomorrow to finish, if the rain holds out. So far, everyone has been very nice and welcoming.


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12 hours, not bad.

Google said it would take 11.5 hours to get here and it took us ten minutes over 12 hours. That's not bad at all considering what we were towing. The truck did much better than I thought, I think I was over estimating the weight of the machine.
I have been receiving lots of E-mail updates from the Chunkin crew and they are complaining about the amount of rain they received. Basically, the field is muddy and they are trying to fix it. Most teams will seated this morning and the rest will be seated throughout the day. We should be at the field soon, just finishing breakfast. Once we get there we will wait for our pit assignment, then start setting up.

On our way

We are on our way to Punkin Chunkin. Just outside Youngstown Ohio. We will probably get to the hotel around 10 or so tonight. It doesn't really matter what time, though, since the launch field is apparently do flooded they aren't letting anyone start setting up until Wednesday. That has to throw off some of the larger teams.

Lake Orion Pumpkin Launch 2009

Well, the launching is over and we are.....not the winner. Absolutely ridiculous. I mean, if you start a competition and are in charge of it, you think you could rig it so you win it. Of course that is not the point of the Launch. I wanted it to be a straight up competition and it was. The sad truth is that we didn't kow our machine well enough. After reviewing the footage post-event I realized that our launch angle was too low. We were releasing at about a 30-35 degree angle, not the 45 degrees that we wanted. I will be watching this very closely at Punkin Chunkin in two weeks. I plan on bringing all of my technology to bear on this event. I will have the slow motion video camera, the mobile broadband enabled laptop and possibly an accelerometer attached to the throwing arm to determine if that throw was more forceful than the previous.
I know that I said I would blog live from the event (sorry Joe) but I was too busy running the event and running the machine to even think of blogging. Hopefully things won't be so hectic at Punkin Chunkin. I will certainly keep everyone up to date on our progress. See you November 6th-8th.

Lake Orion Pumpkin Launch

The Lake Orion Pumpkin Launch is this Saturday and preparations are going very well. First we found out that it takes 2 people about a day to completely disassemble Telos. Next we found out that it takes 2 people about a day to assemble Telos. That was a great revelation. WE had been anticipating 3 people 2 days. We are very excited about this. We expect to have videos and details about Telos available starting on Sunday. Pictures of Telos have already been published in the Lake Orion Review and in Teachers Discovery catalog. In the catalog, Telos is listed for sale for a very high price. We are not really looking to sell it, but if someone wants to pay that much, we will make them their own.
I plan on blogging live from the Lake Orion Launch so if you are interested in our distances check in periodicially. The event starts at 11 and the measured launches should be in by 12.

Launch Party

Yesterday, Saturday, we had our private launch party. We invited some family and friends and all of our sponsors and helpers. It was a great time. I was very nervous for our first launch. Let's be honest, these people have been waiting to see this for over a year. What if something went wrong now? I've told them that it has worked but it's one thing to hear it and another to see it. We launched out first pumpkin too. It was grown in my backyard. It was a little heavy, 9.8 lbs, but it flew well and landed hard. I took a bunch of the people into the field to see it hit and it was pretty cool.
One thing that was of interest. The last time we launched before this we had been checking the release angle. Our last launch of the day had been shorter than the previous so we knew we had turned it too far. When we launched yesterday, it was far short of where we left it. Nothing had changed, just was shorter. We were able to get it back to a normal distance but it was weird. I guess that's the "nice" thing about using wood.
Also, we are going to have some shirts for sale on our website through Zazzle.com. We are also going to be selling our release pins on the website. These are great if you want repeatability out of your machine.

Medium trebuchet a success

We had our first public launch with our new medium trebuchet. It actually worked, repeatedly! I have some serious doubts that it would hold together after repeated launches. We do have one or two things to modify but nothing serious, a washer here, a cable there. I have to admit that I am already designing a new medium trebuchet for just such an occasion. I want one that is easily assembled by one person. I think I have that part figured out, now I want to come up with a way to launch and re-launch quickly with one person. I am planning on working on this over the winter and spring. I want to make it a more robust machine and not give to much worry to distance. It's for pubic launching and the public is still awed but 100 ft, not just 150ft. That's something that I forget.

New treb problems

So after last years Lake Orion Pumpkin Launch we had to remake the medium trebuchet, for the third time. This time I decided that it would be good to create an OB jr. team. The medium treb is theirs, wi fli hi, is the name. I'm not really sure what it means. The thing is that we have done this several times and, even though we did change a couple of things, we are always running into problems. I just can't seem to figure this stuff out without an actual trial and error. Maybe by next year I will be able to just build one and have it work. We will be launching it this Saturday at Barn Daze in Orion Township. Should be fun.

Updates

We have had about 10 successful launches and only 2 failed launches on Telos. This is a great ratio. The two failures were to do with the pouch which we have fixed and have since had no failures. Our distance isn't where we want it to be but we are working on every little efficiency that we can.
Our medium trebuchet, or wi fli hi, as our O.B. jr team has named it, is coming along very well. We have the box large enought o hold about 500 lbs. of weight, we have 2 new axles, and I am picking up some bearings and shaft collars today. We will be at the barn on Saturday and hopefully get everything fixed and ready to go. I am hopefull that we can get about 300 or more feet from wi-fli-hi.
One last thing, we started using a laser range finder to measure our launches. If you have access to one of these, use it! It's great. You just hold it up, put your machine in its sights, and shoot the distance. It's very accurate.

It works

It's been a long couple of months with some ups and some downs. The ups were when we got the frame up, got the arm together and today. The downs were when we couldn't lift the arm into place, when the hoist failed (funny video coming later) and plenty of others.
But today was worth it. We made two successful launches. The machine worked beautifully. With the bearings that we are using it is so silent. I really can't believe it. If nothing else, the silence is worth the extra cost for the bearings. We did have one problem that pretty much wrecked our pouch but I realized that we need a check list before we launch to ensure that no stupid little mistakes are made. We will be out at the test range sometime this week to do some more launches with new pouches. Just for S**** and giggles I emailed Dupont about getting some Kevlar. We'll see.

Oakland Ballistics jr. update

Yesterday, 3 members from OB jr met to do some work. They finished their Medium Treb and did a few launches. First, it was hot here, 87 with high humidity. Though we have some issues to work out the final launch of the day was very successful and matched the simulator, A-treb's predictions almost perfectly. They will be entering in the 15 and under division of the Lake Orion Pumpkin Launch this year. Good luck to them.

Delivery!

We were out working on the throwing arm Sunday and our fabricator stopped by. He had all the steel parts that we needed. I believe that means that we have all parts for Telos. That's pretty cool. Cal (fabricator) did a great job anticipating our concerns. He even had a great idea of how to construct this thing. It's a cool idea and should be fun to implement. I'll let you know how it goes.
On another note, we have been contacted by Teacher's Supply about having our Mini Treb's in their catalog. They would also like to use one of our larger treb's for the cover of their science catalog. We will see what they think of our trebs in person but I am hoping to have Telos take that spot.

Telos is sealed

The wood that we are using for Telos is engineered lumber by Boise. Like any other wood, it has to be protected from the weather. The Lumber comes with a small protection against UV and rain but it needs to be sealed. Since the glue prevents anything from penetrating like regular wood sealant needs to, we had to find something that makes it's own shell. What we found was expensive but it looks like it will work.
We put one full coat on yesterday and put a second coat on parts until we ran out. It looks like it's going to work very well. At $100 a gallon, it better.

CAD might be done

I think I am finally done with the CAD drawing. Well, at least until something comes up. I guess I am done with the CAD drawing (sketchup) as far as all of the reconfiguring is concerned after we did some simulator work. I was really putting it off, but I found an easier way to do the work and it wasn't that bad.
On another note, we got word from our fabricator friend that most of the steel will be "donated". How cool is that! That should bring the cost down considerably.
I'm a teacher and school is out in about 2 weeks. Once the Job is out of the way I can get down to business.

Going Well

I don't have much time but, we completed the frame. It is amazing. I'm not going into too much detail but it really was great. It took a long time to complete but it was completed. All 3 members of our team were there.
Now we are trying to get the metal work completed and figure out how best to construct the rest of it. I can assure you that it will be a system of hoists, pulleys and trolleys.

Throwing Arm

After consulting some more with our architectural consultant, Marty, We decided to widen the arm from 3 1/2" to 5 1/4". This slightly wider arm will be about 10 times stronger left to right than the 3 1/2" arm was. We will put spacers in between the arm which will get it to the desired width and still keep it about the same weight.
I am in the process of widening the Sketchup file. I decided to take this opportunity to cleanup the model. Things have been piling up and getting a little out of hand. I don't like clutter and it kills me to have all of these different parts lying around in the file.
Regardless, things are looking up. I am going to check the CW axle strength and then I believe that's it for now. Once I contact a fabricator to do the remaining steel work I can make the final changes to the model and be done.
On a side note, construction of the machine has been a nagging concern for sometime now. We are going to be doing this with a skeleton crew and no machines. This makes every lift a challenge. I have been designing an overhead hoist that will fit on to the A-frames. It will help lift the main section of the throwing arm into place so we can slide the axle through. It may even help with the long section but I haven't determined if that is possible. It won't be very big and will help a great deal. The previous idea was a large stand whic had to be exactly the right height or the axle wouldn't slide through. This way we can raise or lower the arm to get it to where we need it.

Medium Treb 3

Work has been started on Medium Trebuchet 3, at least that's what we are calling it. We are rebuilding it since we pushed it beyond its limits at LOPL 08. It's going to be the same basic size and design. The size has worked well for demonstration purposes and portability. The purpose of this build is for our Oakland Ballistics jr. team which will be headed by one of my eighth graders, Geoff Becker. Since they are a jr. team they only need to launch a 5 lb. pumpkin so we optimized the design using A-treb. I hope to finish work on it next week while my school is on spring break. A-treb says a distance of about 200 ft. with 250 or 300 lbs. I am partially using this as a determinant of A-treb since it was about 40% too high on the tennis ball treb and right on the mini treb.
Speaking of the mini's, they are still selling well. We average about 2 a week. That might not sound like much, but it's good enough for now. That should allow us to completely fund Telos.
Speaking of Telos, it's moving along well. I am still figuring out the engineering numbers. It's tough,there just aren't as many siege weapon engineers around as there used to be. One thing that has helped is reading the posts from Yankee Siege. They did a great job of describing their thought process as they figured out their new arm. Start with march or so of 08'.
I have increased the size of the plates on the throwing arm, and I am almost finished with a working design for the long end of the throwing arm, though the final design could change in favor of being more efficient. Right now, though, I aiming at funtional. Once we can launch we can be more creative with our time. Once I have those two things figured out that's it for design. Then it's just a matter of building. We are looking to get help with ordering and fabrication of the few remaining steel parts that would be needed. Hopefully I will know something in about 2 weeks. Until then, tell your friends, LOPL 09 October 17th.

Spring is coming

Well, we took a month or two off after our crazy busy Christmas season. We sold the Mini's very well. We were averaging 1 1/2 mini's per day online and a bunch for the stores. Even with all of those sales, we are still woefully short on funds. I have done the numbers though and we are looking good over time.
Now on to the hard stuff. We purchased the A-treb simulator. It's really fantastic. It's a must buy for anyone who wants to build a big trebuchet, over 6 ft. It gives you all the numbers that you could possibly need. It also forces you learn about your trebuchet and the materials. Totally worth the $19.95.
After looking through it for a while we realized that the forces involved in Telos got really big, really fast. We tried increasing the CW by 50% and it increased the forces on the axles and frame by over 100%! We are settling into a comfortable CW zone for our trebuchet. It's a lot of weight and should be sufficient for us to do a good showing. In order to come to these realizations, I had to learn how to be an engineer. It's not that hard if you are willing to partner with your browsers Google toolbar and ask it lots of questions. Eventually I was able to understand what was going on and how to adjust it. It's very exciting to understand these things. I am now working on designing a cable-stay for the throwing arm. I beleive that the cable-stay combined with the Versa Lam lumber will be sufficient. There's a website, http://www.efunda.com/formulae/solid_mechanics/beams/casestudy_display.cfm?case=cantilever_endload
that will tell you if your throwing arm is sufficient for the forces involved. You need to know several very specific numbers for your arms material (Google) and you will need to know the forces being involved.
I will start to update the blog more regularly, I got out of the habit and have been focusing on other aspects. There is a lot going on and I want to tell you about all of it, I just have to take the time to slow down and do it.