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Re: Bottle Rocket B

Posted: March 23rd, 2011, 4:32 pm
by Primate
Flavorflav wrote:
Primate wrote:Winning time for the NY state competition (division c trial event) was 21.5 seconds.
The wind was a real factor, though. It cut our expected time in half.
Oh absolutely. Our first rocket got knocked off course pretty significantly, and flew for only 13 seconds. We'd been getting right around 20 seconds with that one consistently in practice. We got so lucky with our second rocket, which we never even got to test before the competition--the wind died down at the moment we launched.

Their policy on wind was fair, I suppose, but could've been better. The event supervisor was firm on launching the moment he pressurized it--no waiting for the wind to die down. (Delaying filling up the water obviously wasn't helpful, since the wind changed pretty significantly during those thirty seconds.) Technically, though, we're allotted ten minutes, so I don't see why we couldn't eat up part of that time waiting for the right second. Yes, some ten minutes intervals will be windier than others, but it virtually guarantees each team has a shot at a calm flight.

Re: Bottle Rocket B

Posted: March 26th, 2011, 10:09 am
by Brucester
If you read my post before you've read why a well-balanced rocket should handle wind just fine and actually improve times from it. With a manual pump I could pumped it to 90psi. I'm 5'10" and 114lbs... My friend who's around 90-100lbs could pump it to 75psi (with a tad bit of effort, but it was done! :lol: ).

Re: Bottle Rocket B

Posted: March 26th, 2011, 7:41 pm
by fishman100
We had the State Tournament today; after we launched and had our best rocket go only ~12 seconds, we found that the launcher was tilted. Oh well :P

Re: Bottle Rocket B

Posted: March 27th, 2011, 2:23 pm
by Rocketeer
Any advice for a newcomer? Only just found out about getting to go to the competition, which is in three weeks. Finished building the launch pad today with home-made bottle stopper and it finally works! Teammate bowed out so I am working solo on rocket designs.

Re: Bottle Rocket B

Posted: March 27th, 2011, 2:47 pm
by Cheesy Pie
Backslider
Not disastrous in windy or rainy weather
Fins at 20-30 degrees angle
And, most importantly, doesn't break any guidelines.

Re: Bottle Rocket B

Posted: March 27th, 2011, 3:00 pm
by space scientist
Rocketeer wrote:Any advice for a newcomer? Only just found out about getting to go to the competition, which is in three weeks. Finished building the launch pad today with home-made bottle stopper and it finally works! Teammate bowed out so I am working solo on rocket designs.
One thing is that at the tournament you will have to have a partner. When I went to my first invitational this year, my partner didn't come, so I decided that I would launch without a partner. However, the proctors wouldn't let me launch alone which caused me to have to pick a friend of mine to be my partner. There is also an advantage in having a partner in that there are two people who can do the building and launching.

Re: Bottle Rocket B

Posted: March 27th, 2011, 5:32 pm
by andrewwski
Not sure how the rules are worded, but usually it's "team of up to 2". So you really shouldn't need a partner...although it's definitely beneficial to have one, even if they haven't worked on the event at all.

Re: Bottle Rocket B

Posted: March 27th, 2011, 5:47 pm
by Cheesy Pie
It is especially important to have a wind-resistant rocket, because - as I have said 30 times already - my first rocket fell apart due to the wind.

Re: Bottle Rocket B

Posted: March 27th, 2011, 9:51 pm
by Brucester
space scientist wrote:
Rocketeer wrote:Any advice for a newcomer? Only just found out about getting to go to the competition, which is in three weeks. Finished building the launch pad today with home-made bottle stopper and it finally works! Teammate bowed out so I am working solo on rocket designs.
One thing is that at the tournament you will have to have a partner. When I went to my first invitational this year, my partner didn't come, so I decided that I would launch without a partner. However, the proctors wouldn't let me launch alone which caused me to have to pick a friend of mine to be my partner. There is also an advantage in having a partner in that there are two people who can do the building and launching.
You don't need a partner in any event. The rules don't require it, as stated before by the admin..."a team of up to two." The event proctor was wrong, but it was an invitational, so it's nothing unusual there. I've gone up and taken two medals in an event because I had no partner. In regard to the first person I quoted, you need to understand the many key balances in rocket building. Here are the one's I would consider most important:

CG vs. CLA
Light-weight vs. Strong enough to withstand pressure and forces from flight
Slowness of backslide vs. Height

The CG vs. CLA you can easily do some quick research on to get a general idea. With the second one, you want a lightweight rocket because it will be able to go higher and descend slower. The lower weight will make the backslide better because the lift that the surface area creates will have a greater effect on a lighter rocket. The CG vs. CLA also relates to the third one. There is a trade off with how slow you make the backslide vs. how high the rocket goes on take off. The slowest backslides occur when the rocket stays perfectly horizontal and just twirls. Now the balance of the CG and CLA to have this happen will not promote a high take off. Therefore, you must find a good balance between the two.

Re: Bottle Rocket B

Posted: March 27th, 2011, 9:54 pm
by Brucester
fishman100 wrote:We had the State Tournament today; after we launched and had our best rocket go only ~12 seconds, we found that the launcher was tilted. Oh well :P
Argh! That's unfortunate! I know I always ask to adjust the launcher and move it around to find the flattest possible place before I launch. I'm pretty sure it's legal too.