Scrambler B

[Kenshi Takahashi]

reed303, that rule was in place when I competed. Perhaps it's not clear from just pictures: the mass does in fact stretch the rubber as it falls, with the rubber originally starting unstretched. It is clearly demonstrated in this video: https://www.youtube.com/watch?v=HKisLACH9fU.

OK, I think I've got it! Thank you so so much
One last question. In this video the falling mass is cut off so we can only see the rubber band, and the video begins with the rubber band taut. Was it simply because the beginning slack rubber band was cut out or does the rubber band start off stretched?

For some runs I started with the mass at the bottom and triggered the bow release by hand because I didn't like dropping the mass every time.

Oh OK, thank you

[bernard]

I'm posting some messages with permission because I think the details will be helpful to all trying to understand spring launchers.

Basically is this what happens?

1) The rubber band is attached to a hook on the top and extends downwards, where it divides into an "isosceles triangle" of fishing line which is anchored at its bottom two corners by two more hooks at different ends of the launcher.
2) There is a notch in the ETV which holds the base of the fishing line isosceles triangle.
3) The ETV is drawn back with the base still in the notch; the triangle is now "inverted" and faces towards the back of the launcher, not out at the track.
4) The ETV has a loop at its base on the back which the archery release is clipped onto.
5) When the mass falls, the rubber band stretches and falls onto a rubber band which activates the trigger of the archery release, which in turn releases the loop of the ETV. The energy of the rubber band forces the fishing line to return back to its original triangle, and it carries the ETV along with it (as the fishing line is attached to a back dowel in the groove). The cart's forward velocity forces the fishing line to fall out of the groove and it's on its way down the track.

In essence, it is basically like a bow and arrow/crossbow? Where the fishing line extending horizontally across the launcher is drawn back like a bow string and released?

I think you have the right understanding. There are two isosceles triangles, both with coincident base vertices at the eyebolts. One has the third vertex "hooked" onto a notch in the back of the ETV; the other has the third vertex tied to the rubber bands.

Be sure not to attach metal components to your spring launcher because if your spring snaps, it can hurt and break your ETV. I started with S-hooks and when my rubber band broke, it shot through my ETV, breaking the 3D printed part. It was the week of states and I didn't have time to reprint, but thankfully I had a backup piece.

Also do you have a recommendation for fishing line? i.e. some are more elastic/stretchy than others.

It's possible slightly elastic fishing line may keep its stretched form, so I'd recommend leaving all the stretching to your rubber band and use non-elastic fishing line. 20 lbs capacity should be sufficient, and you don't need a huge roll of it.

The rubber I used is Tan Super Sport from a Wright Stuff kit. Like motors in Wright Stuff, any loop you use for this event will need some "breaking in" (the length of the rubber loop may increase 1-2 inches the first couple of stretches). A long length looped 2-3 times through two o-rings should work well.

[cool hand luke]

5.e states the pointed tip of the egg must start on the start point. This means the egg must be held vertically and the pointed tip on the ground. This is contradictory to how they wrote the instructions for mounting the egg. So which one gives? do we ignore the talk on how to mount the egg, or where the egg must be at the start?

I've submitted multiple FAQ's with similar rule incompatibilities to the national web page. Do they ever answer these?

[Unome]

5.e states the pointed tip of the egg must start on the start point. This means the egg must be held vertically and the pointed tip on the ground. This is contradictory to how they wrote the instructions for mounting the egg. So which one gives? do we ignore the talk on how to mount the egg, or where the egg must be at the start?

I've submitted multiple FAQ's with similar rule incompatibilities to the national web page. Do they ever answer these?

I'm not too familiar with Scrambler, but I'm fairly certain that the rule about the tip being at the start line means that the tip should be facing forward and aligned with the start line (or possibly slightly further back; not completely sure).

Regarding FAQs, they do answer those, but it generally takes a few weeks as they have to send it through all of the members of the relevant rules committee to make sure they don't end up issuing something incorrect.

[bernard]

A track diagram for Scrambler is posted on the national website: https://www.soinc.org/scrambler_b.

[dragonfruit35]

5.e states the pointed tip of the egg must start on the start point. This means the egg must be held vertically and the pointed tip on the ground. This is contradictory to how they wrote the instructions for mounting the egg. So which one gives? do we ignore the talk on how to mount the egg, or where the egg must be at the start?

I've submitted multiple FAQ's with similar rule incompatibilities to the national web page. Do they ever answer these?

I'm pretty sure the egg is laying down, not vertical. (the narrow end is at the start point)

[Person]

5.e states the pointed tip of the egg must start on the start point. This means the egg must be held vertically and the pointed tip on the ground. This is contradictory to how they wrote the instructions for mounting the egg. So which one gives? do we ignore the talk on how to mount the egg, or where the egg must be at the start?

I've submitted multiple FAQ's with similar rule incompatibilities to the national web page. Do they ever answer these?

I'm not too familiar with Scrambler, but I'm fairly certain that the rule about the tip being at the start line means that the tip should be facing forward and aligned with the start line (or possibly slightly further back; not completely sure).

Regarding FAQs, they do answer those, but it generally takes a few weeks as they have to send it through all of the members of the relevant rules committee to make sure they don't end up issuing something incorrect.

rfscoach also mentioned that clarifications just opened Saturday, so they won't be out immediately.

[Stephen Science]

So for the 2016-2017 Science Olympiad year, we can use a spring launcher and it follows the rules (as in the energy being used), correct?

[bernard]

So for the 2016-2017 Science Olympiad year, we can use a spring launcher and it follows the rules (as in the energy being used), correct?

The spring launcher is just a general approach. It is possible to make one that complies with the rules. But there are also ways to make one that does not comply with the rules.

[Stephen Science]

So do the two spring launchers on the Scioly wiki page both comply with the rules?