Scioly.org

Another way to fix this problem is to have some friction between the ball and the rocket. You can do this by adding some cardboard around the ball when it is on the rocket, as in Fig. 1.
Or, you can cut up a long bottle (like a perrier bottle) and put the ball in the mouth on top of a stopper, as in Fig. 2.
https://docs.google.com/drawings/d/1qhX ... sp=sharing
This way, as the rocket falls, the ball is dragged along and the parachute is pulled open before the ball is released from the rocket.

Based on a prior thread and my understanding, using an nozzle end half of a bottle as your nose wouldn't pass rule 3c which states "The nose of the rocket must be rounded or blunt at the tip". Though the nose wouldn't touch the inside top of the cap, it's not rounded and the "cookie cutter type edge" of the bottle opening wouldn't qualify as blunt either.

rayner wrote: ↑January 6th, 2020, 9:53 pm Based on a prior thread and my understanding, using an nozzle end half of a bottle as your nose wouldn't pass rule 3c which states "The nose of the rocket must be rounded or blunt at the tip". Though the nose wouldn't touch the inside top of the cap, it's not rounded and the "cookie cutter type edge" of the bottle opening wouldn't qualify as blunt either.

I don't know what kind of bottles you have, but normal bottles aren't sharp.

Whether a bottle passes the "bottle cap test" or not depends on whether you allow "placed" to mean "screwed down" (I don't think it does, so the bottle passes the test). The lip of a plastic bottle is both blunt and rounded. It doesn't have sharp edges - it is quite deliberately rounded in the manufacturing process so that people don't cut their lips. The rounding may have a fairly small radius, but it is clearly rounded.

knightmoves wrote: ↑January 7th, 2020, 12:35 pm

rayner wrote: ↑January 6th, 2020, 9:53 pm Based on a prior thread and my understanding, using an nozzle end half of a bottle as your nose wouldn't pass rule 3c which states "The nose of the rocket must be rounded or blunt at the tip". Though the nose wouldn't touch the inside top of the cap, it's not rounded and the "cookie cutter type edge" of the bottle opening wouldn't qualify as blunt either.

I don't know what kind of bottles you have, but normal bottles aren't sharp.

Whether a bottle passes the "bottle cap test" or not depends on whether you allow "placed" to mean "screwed down" (I don't think it does, so the bottle passes the test). The lip of a plastic bottle is both blunt and rounded. It doesn't have sharp edges - it is quite deliberately rounded in the manufacturing process so that people don't cut their lips. The rounding may have a fairly small radius, but it is clearly rounded.

We're free to interpret it however we want but I don't think the opening end of the bottle satisfies what they are trying to achieve by saying it needs to be blunt or rounded. Another example is if you took a pencil and used it for the tip of your rocket. Clearly the sharpened end wouldn't pass but if you turned it upside down and used the flat or rounded eraser end as the tip, would you presume it's legal since it's not sharp? Or if the eraser was rounded that it was rounded? I wouldn't risk getting tiered because that rounded and blunt end of the pencil could fit inside the cap.

rayner wrote: ↑January 8th, 2020, 2:57 pm Or if the eraser was rounded that it was rounded? I wouldn't risk getting tiered because that rounded and blunt end of the pencil could fit inside the cap.

Based on my interpretation the bottle opening is totally fine. The reason why the rounded pencil eraser wouldn't work is because it fits inside the cap and touches the cap top (see rules manual for a diagram). The tip of the nosecone or any other system you use must NOT touch the top of the cap, which a bottle opening doesn't unless you screw it firmly it (which isn't the same as placing it).

Xiangyu

rayner wrote: ↑January 8th, 2020, 2:57 pm Clearly the sharpened end wouldn't pass but if you turned it upside down and used the flat or rounded eraser end as the tip, would you presume it's legal since it's not sharp? Or if the eraser was rounded that it was rounded? I wouldn't risk getting tiered because that rounded and blunt end of the pencil could fit inside the cap.

A pencil would fail the bottle cap test (but would be blunt). The rules say that the rocket nose must both be blunt/rounded and pass the bottle cap test. They do not say that the bottle cap test defines blunt/rounded (meaning I think a cookie cutter would be illegal even though it would pass the bottle cap test).

A bottle neck would pass the bottle cap test (the bottle only contacts the top of the cap when you screw it on - if you just "place" it, the cap is held up by the threads.) The outstanding question is whether a bottle neck is either blunt or rounded. I claim it is rounded, quite deliberately, in the construction of the bottle, and so it would be legal. The rules don't specify a minimum radius of curvature - they just say "blunt/rounded", which I think we must therefore interpret as "not sharp".

So if you want to do the 6 foot long tube as nosecone thing that I have seen, and nestle the ping ping ball in the end of the tube, I think you'd be fine, as long as the tube is wider than a bottle neck, and that you took a file to the end of the tube to round off any sharp bits from cutting / manufacture.

(As ever, just my opinion, and it's worth what you paid for it.)

Has anyone competed at an invitational using this approach and can confirm it was considered legal?

That would certainly make this easier if that's true - i.e. tube opening being sufficient and allowed?

Accidentally duplicated post - ignore...

gmui wrote: ↑January 9th, 2020, 9:35 pm Has anyone competed at an invitational using this approach and can confirm it was considered legal?

That would certainly make this easier if that's true - i.e. tube opening being sufficient and allowed?

It was legal at LISO but not at regionals - they said i didn't have a "nose cone".

gmui wrote: ↑January 9th, 2020, 9:35 pm Has anyone competed at an invitational using this approach and can confirm it was considered legal?

That would certainly make this easier if that's true - i.e. tube opening being sufficient and allowed?

was legal at northview. I don't see why the event supervisors at that regionals mandated a nose "cone", the tube definitely passes both the bluntness and bottle cap test