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scio_musca wrote:Hi,
Wanted to find out what flight times other schools are getting. We are currently getting a flight time of 10 seconds. Is this good enough to do well at regionals and state?

I got a constant 11 sec... Until it crashed in the teachers lounge.

Hello, I know that parachutes are not allowed in Bottle Rocket but are wings?

scio_musca wrote:Hi,
Wanted to find out what flight times other schools are getting. We are currently getting a flight time of 10 seconds. Is this good enough to do well at regionals and state?

10 seconds should be fine for regionals, although something like 15-20 is a good target for states/nationals.

Toms_42 wrote:

scio_musca wrote:Hi,
Wanted to find out what flight times other schools are getting. We are currently getting a flight time of 10 seconds. Is this good enough to do well at regionals and state?

10 seconds should be fine for regionals, although something like 15-20 is a good target for states/nationals.

Looks like we're still as good as we were before, then.

scio_musca wrote:Hi,
Wanted to find out what flight times other schools are getting. We are currently getting a flight time of 10 seconds. Is this good enough to do well at regionals and state?

I'm in division C so I haven't read the rules but at 10 seconds, I'll bet you have a "lawn dart". There are plenty of things you can do to fix this but, since I don't have a copy of the rules, I'd have let you determine if they are allowed.
1. Can you drop the nosecone weight at apogee? Probably not but this adds a great amount to your time if allowed.
2. How long can the rocket be? With a longer rocket, you have more leeway to adjust important parameters such as CLA (center of lateral area), CG (center of gravity) and the always hard to determine: CP (center of pressure).
Going up, if the CG is at least one diameter (average width of the rocket) ahead of the CP, it will fly straight. Coming down, the physics is different. If the CP (the point that we can consider the atmosphere pushing on the rocket), roughly coincides with the CG, it should fall flat instead of nose down.
In a nutshell, if you can design a rocket with a CLA just ahead (toward nose an inch or so) of the CG and provide a perfect combination of nosecone weight (moves the CG toward nose) AND fin size (moves CP backwards, away from nose) you can create a "back slider". I have one that I built that can reach 150m at 60 psi and has stayed aloft for 27 seconds.
Again, I have no idea what the rules state but you might want to Google "back slider water rocket". There is plenty of info out there on this. One of the most famous is the "Coney" which has a ridiculously long nose cone.

It is really neat watching these backsliders reach full height and then literally pausing at apogee followed by a short backward (yes backward!) slide downward until, within meters, they become horizontal with the earth and fall slowly and gently down with the fins spinning like a pinwheel. You don't have to worry about a backslider destroying itself on landing. In fact, if you were to get hit by one of these, it wouldn't hurt at all. Meanwhile, one of my lawn-dart rockets put a large dent in the roof of my truck!

joeyjoejoe wrote:In fact, if you were to get hit by one of these, it wouldn't hurt at all. Meanwhile, one of my lawn-dart rockets put a large dent in the roof of my truck!

That sounds horrible. I've almost hit my coach with a bad rocket once. It was the first design I had ever made, and I didn't quite understand the rocket science.

I ended up okay at the end of rockets. The backsliders were working well and at a comfortable time. We did really well at Nats., too.

A Person wrote:

joeyjoejoe wrote:In fact, if you were to get hit by one of these, it wouldn't hurt at all. Meanwhile, one of my lawn-dart rockets put a large dent in the roof of my truck!

That sounds horrible. I've almost hit my coach with a bad rocket once. It was the first design I had ever made, and I didn't quite understand the rocket science.

I ended up okay at the end of rockets. The backsliders were working well and at a comfortable time. We did really well at Nats., too.

Oh man... In 2011 (I think) We went to an invitational (magsig?) where they held bottle rockets next to a parking lot. My rockets both had golf bag inserts as bodies (The long clear tubes.) One backslid perfectly, but the other lawn darted and slammed into the hood of a car. Luckily it wasn't a super nice car and we left a sticky note with contact info if they found any damage. I can't remember if there were any dents or not, but it was pretty scary walking over to the car...

Also, either that year or the year after, we got 3rd in bottle rockets at nats because it landed on a roof and the timers kept timing it while it rolled off lol.

Toms_42 wrote:

A Person wrote:

joeyjoejoe wrote:In fact, if you were to get hit by one of these, it wouldn't hurt at all. Meanwhile, one of my lawn-dart rockets put a large dent in the roof of my truck!

That sounds horrible. I've almost hit my coach with a bad rocket once. It was the first design I had ever made, and I didn't quite understand the rocket science.

I ended up okay at the end of rockets. The backsliders were working well and at a comfortable time. We did really well at Nats., too.

Oh man... In 2011 (I think) We went to an invitational (magsig?) where they held bottle rockets next to a parking lot. My rockets both had golf bag inserts as bodies (The long clear tubes.) One backslid perfectly, but the other lawn darted and slammed into the hood of a car. Luckily it wasn't a super nice car and we left a sticky note with contact info if they found any damage. I can't remember if there were any dents or not, but it was pretty scary walking over to the car...

Also, either that year or the year after, we got 3rd in bottle rockets at nats because it landed on a roof and the timers kept timing it while it rolled off lol.

It must have been that year; I know we got it in 2012.

Unome wrote:

Toms_42 wrote:

A Person wrote: That sounds horrible. I've almost hit my coach with a bad rocket once. It was the first design I had ever made, and I didn't quite understand the rocket science.

I ended up okay at the end of rockets. The backsliders were working well and at a comfortable time. We did really well at Nats., too.

Oh man... In 2011 (I think) We went to an invitational (magsig?) where they held bottle rockets next to a parking lot. My rockets both had golf bag inserts as bodies (The long clear tubes.) One backslid perfectly, but the other lawn darted and slammed into the hood of a car. Luckily it wasn't a super nice car and we left a sticky note with contact info if they found any damage. I can't remember if there were any dents or not, but it was pretty scary walking over to the car...

Also, either that year or the year after, we got 3rd in bottle rockets at nats because it landed on a roof and the timers kept timing it while it rolled off lol.

It must have been that year; I know we got it in 2012.

Was definitely that year, the roofs for 2011 were horrible. My partner's rocket didn't get stuck, but a lip of a roof tipped the rocket like 40 ft off the ground for it to slide down it vertically, if I remember correctly.

There were literally like no roofs in 2012, if I remember, except the one building which was away from the wind. That was the year the rockets somehow were helped by the wind through some accidental construction, it seemed.

If a component opens. and nothing comes apart. is it considered separation.