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Re: Egg-O-Naut C

Posted: May 9th, 2010, 8:45 pm
by starpug
with our design we put, 535 ml and 800ml of water and it went up to about 150 feet
The question is how did you keep the nose cone from fusing onto the bottle when that happened :P
we have stoppers, i'll post a pic, the bottom half shoots up and when it is out of juice the top keeps going forward and at the top it all seperates, it has gotten3 to 4 minutes consistantly.
You're the one with the 15 foot nose cones right?

Re: Egg-O-Naut C

Posted: May 9th, 2010, 8:48 pm
by cypressfalls Robert
lol yea, but we changed the design to a totally different one, and works a little better, ~30 seconds

Re: Egg-O-Naut C

Posted: May 9th, 2010, 8:53 pm
by starpug
lol yea, but we changed the design to a totally different one, and works a little better, ~30 seconds
With shorter nose cones? You just said you were getting 4 minutes?

Re: Egg-O-Naut C

Posted: May 9th, 2010, 9:18 pm
by cypressfalls Robert
yea, just wait for the pic

Re: Egg-O-Naut C

Posted: May 10th, 2010, 2:52 pm
by rocketman1555
Yeah! that would be great if you told me about stability and how to stabilize it! would you put the fins under the cone??
The basics of stability are that you have to have the Center of Mass (also called Center of Gravity) above the Center of Pressure on the rocket. 1 diameter is usually recommended on model rockets. The simplest way to determine center of mass is to load your rocket with both the egg and water, and then suspend it from a string, and find where it is balanced on the string. To find Center of Pressure you can just make a flat cardboard cutout of your rocket and balance that, which can probably be done on a finger. You then mark the Center of Pressure on the bottle at the same location it is on the cardboard cutout.

If the center of mass is behind the center of pressure then your rocket won't be stable, and if they are relatively close together then it is only marginally stable. To increase stability you have a few options. You can make the rocket longer, make bigger fins, or add more weight to the front. I prefer to make the rocket a little longer, because about one extra bottle length really helps.

I'll try to post some pictures of how to do this in the next few days.

Re: Egg-O-Naut C

Posted: May 12th, 2010, 3:03 pm
by cypressfalls Robert
with our design we put, 535 ml and 800ml of water and it went up to about 150 feet
The question is how did you keep the nose cone from fusing onto the bottle when that happened :P
we have stoppers, i'll post a pic, the bottom half shoots up and when it is out of juice the top keeps going forward and at the top it all seperates, it has gotten3 to 4 minutes consistantly.
here's a rough paint sketch:this is without fins on the drawing, not on the real thing!
Image

Re: Egg-O-Naut C

Posted: May 17th, 2010, 4:27 pm
by Cheerwine
How seriously do they take the pointed nosecone rule? I don't think my pointed nosecone is sharp enough to hurt anyone, but I don't want to get dq'ed either.

Re: Egg-O-Naut C

Posted: May 17th, 2010, 4:38 pm
by midnightroxy13
At my state they made people cut off the tip, but i don't know how strict they are at nationals because i've never been

Re: Egg-O-Naut C

Posted: May 17th, 2010, 4:39 pm
by starpug
How seriously do they take the pointed nosecone rule? I don't think my pointed nosecone is sharp enough to hurt anyone, but I don't want to get dq'ed either.
Read the clarifications on the nationals site, I would put a ping pong ball on it just to be safe

Re: Egg-O-Naut C

Posted: May 17th, 2010, 7:19 pm
by kjhsscioly
at the IL state competition, i had a rolled nosecone made from plastic, and it was pointed, though not extremely so, but the directors did not say anything about it. As long as you avoid metal tips, i don't think there will be an issue.