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Re: Bottle Rocket B
Posted: Tue Mar 27, 2012 7:05 am
by justinbeiberfan1337
ls20817 wrote:How are you doing the calculations. I have tried to download one and put in the numbers and it didn't work. I am using a cone shaped rocket. Do you need to figure in the shaping at the end near the nozzle. Can any one recommend a good simulation site? Any help would be appreciated.
just go for an aerodynamic backslider, you dont really need that much simulation. Just keep it lightweight, and with a lot of practice you can get a consistant 20-25 second backslide.
Re: Bottle Rocket B
Posted: Tue Mar 27, 2012 7:10 am
by Pi_Lord
jma wrote:ls20817 wrote:How are you doing the calculations. I have tried to download one and put in the numbers and it didn't work. I am using a cone shaped rocket. Do you need to figure in the shaping at the end near the nozzle. Can any one recommend a good simulation site? Any help would be appreciated.
We used programs from this website
http://wrockets.trib-design.com/index.p ... e=programs
this is a good website
http://www.grc.nasa.gov/WWW/K-12/rocket/rktsim.html
Re: Bottle Rocket B
Posted: Tue Mar 27, 2012 7:11 am
by justinbeiberfan1337
jgrischow1 wrote:We can't seem to get above 10 seconds and I am wondering if anyone has any ideas. Yes, I have read this thread, last year's thread, the wiki, and Googled for hours.
We are using a 1 L bottle and about 425 mL of water.
Our nose cone is a long plastic tube, about 5 ft long and 1.5 in diameter.
Our fins are made from plastic folders and folded and taped for rigidity. They are trapezoidal, with bases of 3 in and 5 in and a height of 3 in.
We have two main problems that I see:
Height: The rocket doesn't seem to be going very high.
Delayed backslide: It falls the same way it came up (i.e. the opposite of a nosedive) for awhile before turning and backsliding.
My ideas:
Make the rocket lighter. Take away some tape, shorten the rocket?
Add weight to the tip so it goes up straighter and/or turns to backslide sooner (but we tried this a little and got some nosedives at the end of the backslide)?
Change the fin size/shape?
I don't think we have time to significantly alter the design of the nose cone to, say, paper. Our regional is Saturday.
Any ideas? Thanks.
main thing is go as light as possible. we used a similar design and got 15-20 secondd flights. It is smart to note that that type of long, thin cone is perfect for high winds or rainy days. You mention lawn darting when you went lighter, try to lighten up the rear of the rocket, by using less glue or tape, and only one small bottle with maybe half of a reverse bottle on top to attach the tube to. for the tube, we use long golf bag inserts, which are light and large. try these ideas and you might get better luck. I there is low winds, you can consider an equally loong paper CONE.
-rocketman42
Re: Bottle Rocket B
Posted: Tue Mar 27, 2012 10:38 am
by ls20817
We have been able to get the rocket to back slide. The rocket seems to be spinning pretty fast as it comes down horizontally. Does anyone know of a way to stop or slow the spinning.
Re: Bottle Rocket B
Posted: Mon Apr 02, 2012 9:31 pm
by bluejay
when i build my rocket, it just seems to go really far..unlike the other ones, but i can't find anything on it. please help.
Re: Bottle Rocket B
Posted: Tue Apr 03, 2012 7:52 am
by skillfullparrot7
What are the typical times to expect at state a competition?
Re: Bottle Rocket B
Posted: Wed Apr 04, 2012 1:44 pm
by jma
What is the best way to increase/decrease mass in the back/front of the rocket?
Re: Bottle Rocket B
Posted: Fri Apr 06, 2012 1:08 pm
by fishman100
rocketman42 wrote:ls20817 wrote:How are you doing the calculations. I have tried to download one and put in the numbers and it didn't work. I am using a cone shaped rocket. Do you need to figure in the shaping at the end near the nozzle. Can any one recommend a good simulation site? Any help would be appreciated.
just go for an aerodynamic backslider, you dont really need that much simulation. Just keep it lightweight, and with a lot of practice you can get a consistant 20-25 second backslide.
Also remember to minimize any imperfections on the rocket (air bubbles when taping, etc.) to maximize the flight. And make sure that you have some weight fr stability; don't just build the lightest rocket as possible.
skillfullparrot7 wrote:What are the typical times to expect at state a competition?
If I had to guess, I'd say ~40 seconds for the combined time...but don't quote me on that.
jma wrote:What is the best way to increase/decrease mass in the back/front of the rocket?
You can add clay to an end, change the fin size, change the length of the nose cone, etc.
For those of you who are using glue, what type of glue are you using?
Re: Bottle Rocket B
Posted: Sat Apr 07, 2012 12:42 pm
by drifter601
skillfullparrot7 wrote:What are the typical times to expect at state a competition?
Definitely in the 30- 40 sec. Total.
Re: Bottle Rocket B
Posted: Sun Apr 08, 2012 3:38 pm
by jma
jma wrote:What is the best way to increase/decrease mass in the back/front of the rocket?
You can add clay to an end, change the fin size, change the length of the nose cone, etc.
For those of you who are using glue, what type of glue are you using?[/quote]
Thanks, Fisherman100.
For glue, we used super77 for paper, zap a gap for wood, solvent cement for plastic.