Storm the Castle B

[Jim_R]

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[starpug]

This was by far my favorite event when I was in B Division.


Assuming that the energy rule is still around (I don't see why it wouldn't be) a typical FAT is the way to go for this event (google it)

[fleet130]

Here's a brief rundown of the event for 2011 (Maybe not so brief!):

...1..Powered by falling mass (counterweight & projectiles only)
...2..Projectiles, counterweight, & target supplied by event supervisor
......a..Exact Mass & size not known before competition
......b..May not be modified by contestants
......c..Device must be constructed to accommodate
...3..Counterweight
......a..1-3kg
......b..Counterweight & hook fit in 15cm cube (be prepared for diagonal fit dimensions)
......c..Hook - use is optional
......d..To insure hook fits the device (this is not scoreable, but counterweight may not fit otherwise)
............1).Must have hole at least 9mm dia.
............2).Edge of hole must be no more than 1cm from edge of material
............3).Material must be no more than 6.5mm thick
...4..Projectiles
......a..20-60g
......b..Approximately spherical
......c..No larger than 6cm dia.
......d..Multiple projectiles (if used) will have similar size, shape & mass.
...5..Target
......a..20cm x 20cm x 20cm
......b..Open Top
...6..Entire device (including counterweight & projectile) must fit in 75cm cube when ready-to-fire
...7..Must automatically return to within launch area after each shot
...8..Trigger
......a..is not part of device
......b..May extend out of launch area (before, during &after launch)
......c..May use battery power
......d..May not use radio control (Safety Hazard)
...9..Devices may be modified (using only tools & supplies impounded)
...10. 5 minutes, 3 launches, no practice shots
...11. Need Z87+ (high impact) eye protection (Does not specify type)

Somewhere in the archives, there may be a lengthy discussion on the use of the various types of trebuchets. While it may be possible to build a FAT that complies with the energy rule, complying with the sentence in lines 5 & 6 of Para. 3.f makes it questionable whether it could be viable.
(Edit: I found the info on the energy rule. I have not validated it against the current rules.)

Be sure to read the rules extra carefully. There are lots of pitfalls where you can mis-interpret things. Make sure you understand the "energy rule" (Para. 5.f). This has historically been one of the things teams get burned on.

Caveat Emptor! This is not the rules. Be sure to double-check yourself once you get them. I've tried not to make interpretations and to identify them when I do.

[brobo]

For a FAT trebuchet, would it be better to have the wheels up high on the arm, close to the counterwieght, or down lower?

I'm just wondering because I'm about to start working, but I don't know which would give it more launching power.

[wlsguy]

The ratio between short and long arm length, wheel position, and sling length are what makes this event a challenge. It's hard to say what will work best for your individual design. You may want to try to read over any previous (archived) posts. They have some good information.

[brobo]

Thanks, but I didn't see anything in the OBB. I guess it'll be a matter of trial and error, which I think this event is a lot of.

Does anyone know how wind may effect the event? Will it be held indoors? Or does the wind usually not play a large factor in this event?

[starpug]

For a FAT trebuchet, would it be better to have the wheels up high on the arm, close to the counterwieght, or down lower?

I'm just wondering because I'm about to start working, but I don't know which would give it more launching power.

I would think you'd want it to be at a height so that when the arm is perfectly vertical, the CW just barely doesn't touch the bottom of the device. Any higher and the counterweight hits during launch, wasting energy, any lower and you waste energy by not using all the height allotted to you in the rules.

[Dark Sabre]

Thanks, but I didn't see anything in the OBB. I guess it'll be a matter of trial and error, which I think this event is a lot of.

Does anyone know how wind may effect the event? Will it be held indoors? Or does the wind usually not play a large factor in this event?

Not all of them, but some of the OBB threads on STC:
http://scioly.org/obbarchive/board.php? ... event=STCB
http://scioly.org/obbarchive/board.php? ... event=STCC
there are more in here, but since search is broken, you kinda have to sift

[harryk]

I miss this event
So much better than trajectory

[old]

The ratio between short and long arm length, wheel position, and sling length are what makes this event a challenge. It's hard to say what will work best for your individual design. You may want to try to read over any previous (archived) posts. They have some good information.

There is no single ratio of these variables that will work over a range of projectiles and falling masses. If you want to make the device work throughout the range of possibilities than you need to have the ability to adjust these ratios. The issue then becomes the huge amount of testing needed