Trajectory B/C

[starpug]

Connected to what? gate latch is just screwed on to the piece wood. The latch hooks around the end of the ring like a pincer through the hole in the ring. I'll see what pictures I can find that might explain this

[Jazzy09]

is 50 degrees to high of an angle? i feel like it might hit the ceiling depending on where the event is held but i would think i will need it to shoot that high to hit the closest target, which could be 2 meters away and 2 meters high

[starpug]

Uh well I would count on the facilities being adequate for 50 degrees, but I would also make sure you can still hit all the targets without a 50 degree just in case. But I think you should have plenty of space to use a 50 maybe 55 degree angle even if the event is held indoors.

[captbilly]

is 50 degrees to high of an angle? i feel like it might hit the ceiling depending on where the event is held but i would think i will need it to shoot that high to hit the closest target, which could be 2 meters away and 2 meters high

I don't think it is possible to hit all possible combinations of elevated and ground level targets with a 50 degree release angle. Take a look at some of the trajectory JAVA aplets on the web, or plot it out yourself, but I think you will find that you need about 60 degrees to hit a ground level target at 10 meters when firing over a 2 meter elevated target at 8 meters. Keep in mind that the elevated target is up to 1 meter in diameter so you really only have 1.5 meters between the elevated target and the ground level target under the worst case condition.

As to whether or not the event coordinator will take the ceiling height into account. I was at Nationals 2 years ago watching Storm the castle and several of the very best teams hit the ceiling. I always believed that those teams were unfairly penalized for their superior designs. The event coordinator felt that since all the teams had the height restriction that it was fair but the fact is that only the very best teams had an issue with the ceiling height, because only their trebuchets could shoot that high or far. Essentially what happened is that the team that would have come in first of second ended up comming in something like 25th. I don't really know what strategy you should use to deal with the ceiling being too low. On the one hand you could build a device with adjustable firing angles, but that could be a nightmare to adjust and calibrate. I think with just one firing angle you end up with about 500 possible combinations of elevated and ground level target distances that you must calibrate for. If you include the possibility of having to deal with a ceiling that is too low to use the same firing angle as you need for the worst case elevated and ground level target you could end up with thousands of possible distances and firing angles.

The ceiling height issue is not really dealt with in the rules. In the old STC rules there was a reminder to the event coordinator to keep ceiling height in mind when picking the counterweight and projectile. National SO even published a chart that the event coordinators could use to determine the maximum amount of room that they would need to deal with various combinations of counterweights and projectiles. The problem was that the chart didn't take height into consideration at all, and the charts didn't account for better designs with much better ranges then those that were around when the charts were made. I think the couple of trebuchets that hit the ceiling at Nationals had ranges about 50% longer then the SO charts showed were possible.

At regional and state competitions I think the coaches need to talk to the event coordinator before the competition and make sure that he/she is aware of the height requirements of the trajectories. I am assuming that after what happened at Nationals with STC in Wichita that we won't see a problem with ceiling height at Nationals again. It looks to me as though a 60 degree trajectory requires about 1/2 as much ceiling height as range, so a 10 meter target distance would require about 5 meters of height. Of course if someone had a design that always uses the same amount of launch energy but varies the distance by adjusting firing angle, you could require an 8 or 9 meter ceiling for a 4 meter target distance. I doubt that any event coordinator will have planned for that. I think the best way to deal with these issues is to publish ceiling height info beforehand so teams can have a plan to deal with it. Of course you would really need to know the target elevation and distances as well, and the event coordinator isn't going to publish that in advance.

[academy12]

What do they mean by 4 graphs?

[Flavorflav]

is 50 degrees to high of an angle? i feel like it might hit the ceiling depending on where the event is held but i would think i will need it to shoot that high to hit the closest target, which could be 2 meters away and 2 meters high

It looks to me as though a 60 degree trajectory requires about 1/2 as much ceiling height as range, so a 10 meter target distance would require about 5 meters of height. Of course if someone had a design that always uses the same amount of launch energy but varies the distance by adjusting firing angle, you could require an 8 or 9 meter ceiling for a 4 meter target distance. I doubt that any event coordinator will have planned for that. I think the best way to deal with these issues is to publish ceiling height info beforehand so teams can have a plan to deal with it. Of course you would really need to know the target elevation and distances as well, and the event coordinator isn't going to publish that in advance.

If you can't vary your launch energy, that is a flaw in your design. I don't think you can count on a 9 meter ceiling.

[andrewwski]

What do they mean by 4 graphs?

Exactly what they said. 4 graphs.

[starpug]

is 50 degrees to high of an angle? i feel like it might hit the ceiling depending on where the event is held but i would think i will need it to shoot that high to hit the closest target, which could be 2 meters away and 2 meters high

It looks to me as though a 60 degree trajectory requires about 1/2 as much ceiling height as range, so a 10 meter target distance would require about 5 meters of height. Of course if someone had a design that always uses the same amount of launch energy but varies the distance by adjusting firing angle, you could require an 8 or 9 meter ceiling for a 4 meter target distance. I doubt that any event coordinator will have planned for that. I think the best way to deal with these issues is to publish ceiling height info beforehand so teams can have a plan to deal with it. Of course you would really need to know the target elevation and distances as well, and the event coordinator isn't going to publish that in advance.

If you can't vary your launch energy, that is a flaw in your design. I don't think you can count on a 9 meter ceiling.

Yeah according to my conversions 9 meters is equal to 29.5 feet. So I highly doubt you'll get a ceiling that high, unless they give you another a ballroom or something like where they put the BLG/Wright Stuff. You should probably find a way to figure out what kind of facilities the campus the competition is at has.

[bob3443]

i'm not doing trajectory but i'm just wondering, in the rules does it mention anything about not being allowed to use electronics?

[haven chuck]

It must be powered by a non-metallic, elastic source. You can use a battery powered trigering device, but not a remote control one. Does that answer your question?