Bottle Rocket B

[kendreaditya]

Does anyone have any ideas on how to fix the curve of the fin (its cause by glue)?

I don't see why you should be even using glue. You arn't allowed to use
glue directly on the bottle. If I were you, I would immediatly switch to packaging tape for you're entire rocket.

I am using glue only in the fin, that is allowed according to the rules. I am wondering how to straighten the top of the fin shown in the photo.

[Fanglin]

Does anyone have any ideas on how to fix the curve of the fin (its cause by glue)?

I don't see why you should be even using glue. You arn't allowed to use
glue directly on the bottle. If I were you, I would immediatly switch to packaging tape for you're entire rocket.

I am using glue only in the fin, that is allowed according to the rules. I am wondering how to straighten the top of the fin shown in the photo.

Oh, there's a photo? I don't see one. See if you can re-upload one.

[Fanglin]

Never mind, I see it now

[Fanglin]

Assuming that's the leading edge, I predict that the type of paper you are using is too flimsy for the role. I think the best strategy for fixing this, is to replace the leading edge with something more rigid. My suggestion is a parallelogram of Corrugated plastic, but other materials may work.

[NeBH]

Hi!

This is my first year going to Nationals, so I have a few questions;

I understand that the rules for size parameters are followed very strictly at Nationals, but I was wondering, what about the "The bottle can't have any scratches on it" rule? To put that another way, how deep/big can a scratch/scuff be until you get DQ'ed?

Also, do you have to mark which label came from which rocket? I'm assuming no (based on the rules), but better safe then sorry!

And finally, I've been using duct tape to attach the fins(I used balsa at States, but I'm going to switch to foam board) because it's pretty strong, but is it too heavy?
Should I be using packing tape instead? What have you guys found works the best?

Thanks!

-NeBH

P.S.
I'm from Idaho, and the rules are...
Well, let's just say...
They're not followed as strictly as they could be...
¯\_(ツ)_/¯

[NotoriousRapper]

Hi!

This is my first year going to Nationals, so I have a few questions;

I understand that the rules for size parameters are followed very strictly at Nationals, but I was wondering, what about the "The bottle can't have any scratches on it" rule? To put that another way, how deep/big can a scratch/scuff be until you get DQ'ed?

Also, do you have to mark which label came from which rocket? I'm assuming no (based on the rules), but better safe then sorry!

And finally, I've been using duct tape to attach the fins(I used balsa at States, but I'm going to switch to foam board) because it's pretty strong, but is it too heavy?
Should I be using packing tape instead? What have you guys found works the best?

Thanks!

-NeBH

P.S.
I'm from Idaho, and the rules are...
Well, let's just say...
They're not followed as strictly as they could be...
¯\_(ツ)_/¯

First of all congrats on going to Nationals, it's a lot of fun!

Honestly how strictly they will follow the rules is up to chance. Judging from previous nationals, they'll look for obvious scratches that compromise the structural integrity of the bottle. I personally would rather be safe than sorry, if there's a scratch on it that makes you think they might DQ you at all, just don't bring it as one of your bottles.

You don't need to label, but it can't hurt.

I used packing tape, but I did this the first year and have stopped following the meta around the event. Packing tape worked completely fine, and I didn't notice a flight time difference between duct tape and packing tape. Packing tape was just easier to use and slightly lighter.

Hope this helps!

[NeBH]

Hi!

This is my first year going to Nationals, so I have a few questions;

I understand that the rules for size parameters are followed very strictly at Nationals, but I was wondering, what about the "The bottle can't have any scratches on it" rule? To put that another way, how deep/big can a scratch/scuff be until you get DQ'ed?

Also, do you have to mark which label came from which rocket? I'm assuming no (based on the rules), but better safe then sorry!

And finally, I've been using duct tape to attach the fins(I used balsa at States, but I'm going to switch to foam board) because it's pretty strong, but is it too heavy?
Should I be using packing tape instead? What have you guys found works the best?

Thanks!

-NeBH

P.S.
I'm from Idaho, and the rules are...
Well, let's just say...
They're not followed as strictly as they could be...
¯\_(ツ)_/¯

First of all congrats on going to Nationals, it's a lot of fun!

Honestly how strictly they will follow the rules is up to chance. Judging from previous nationals, they'll look for obvious scratches that compromise the structural integrity of the bottle. I personally would rather be safe than sorry, if there's a scratch on it that makes you think they might DQ you at all, just don't bring it as one of your bottles.

You don't need to label, but it can't hurt.

I used packing tape, but I did this the first year and have stopped following the meta around the event. Packing tape worked completely fine, and I didn't notice a flight time difference between duct tape and packing tape. Packing tape was just easier to use and slightly lighter.

Hope this helps!

Thanks, NotoriousRapper! That helps a lot!

Also, I haven't seen many tube-shaped fins on the internet, but it seems like they're a pretty good design.
I'm thinking they'd be light, and much easier to make straight than "normal" fins.
Am I missing a drawback that makes them unpopular?

Thanks again!

-NeBH

[Zioly]

Am I missing a drawback that makes them unpopular?

-NeBH

They provide less drag on the descent. Just out of curiosity, what times have you been getting at 60 psi, NeBH?

[Fanglin]

Hi!

This is my first year going to Nationals, so I have a few questions;

I understand that the rules for size parameters are followed very strictly at Nationals, but I was wondering, what about the "The bottle can't have any scratches on it" rule? To put that another way, how deep/big can a scratch/scuff be until you get DQ'ed?

Also, do you have to mark which label came from which rocket? I'm assuming no (based on the rules), but better safe then sorry!

And finally, I've been using duct tape to attach the fins(I used balsa at States, but I'm going to switch to foam board) because it's pretty strong, but is it too heavy?
Should I be using packing tape instead? What have you guys found works the best?

Thanks!

-NeBH

P.S.
I'm from Idaho, and the rules are...
Well, let's just say...
They're not followed as strictly as they could be...
¯\_(ツ)_/¯

I'm completly sorry I didn't see this earlier. I believe I can help you a lot.

For the bottle scratches, I believe that anything that might possibly comprimise the structual integrity of the bottle can be called out by the judge, and possibly get you DQed.
But on the other hand, it's difficult to replicate rocket results when you switch bottles. This is really a question up to decide on. Would you call out the bottle because of the scratch? or do you think that a scratch could weaken the bottle? if so, then I suggest that you replace your bottle with an Identical bottle, but make sure that you practice with this new bottle if you change it.

For the labels, I think all judges look for is the "Carbonated Beverage" label, and sometimes a rough corrolation between bottle and label. What I mean, is that they can see if you used a 2 liter coke label for a 1 liter bottle and so on so forth.

If you are using duct tape to attach fins, I suggest that you use the least amount possible, or switch to packaging tape. Attaching fins is really the only place where you should use duct tape. If you have it anywhere else on the rocket, you should switch to packaging tape for weight reduction. If you can, even try packaging tape on the fins, but test to see if it's strong enough to hold them in place before you compete.
The materials you use on your fins seems a bit iffy though. Balsa is a bad material for rockets in general, and I'm glad you noticed that. Foam board might work, but I have a better, weight friendly solution you should maybe check out. I suggest you get Corrugated Plastic boards, and 0.007 inch plastic film to make a sort of hybrid material fin design.

My design consists of a Trapezoid shaped fin, made out of a parallelogram shaped piece of corrugated plastic in the front (make sure the holes are parallel to the leading edge)
and a triangle of flimsy plastic film on the back. The film is pulled taut from being taped between the bottle and the corrugated plastic leading edge. once you have this down, I would pinch the front of the corrugated plastic into a point for better aerodynamics (hence why I suggest that the holes be parallel to the leading edge.) Then tape this onto the bottle.

since I don't know the overall design of your rocket, I suggest that you play around with this design, and work out which variation of this design works best on your rocket.

Good luck at nationals, and happy flying!

[NeBH]

Am I missing a drawback that makes them unpopular?

-NeBH

They provide less drag on the descent. Just out of curiosity, what times have you been getting at 60 psi, NeBH?

Thanks, Zioly!

Unfortunately, my launcher has a pressure release valve that blows at ~50 psi, so I haven't been able to test at 60. Also, it was meant for 2 L bottles.
The manufacturer said that it "doesn't work as well" with 1 L, which I think (after you translate from lawyer-eze to experience-landic, of course) means

"After you work out your

air pressure issues (Click to Show Hidden Text)

There's an adapter that goes from the air hose on the compressor to the launcher. Well, we lost it. So I asked my mom to buy a new one. She did, but we opted for the cheap one. Guess what! It was leaky! Of course, I didn't realize that until I'd spent a few days struggling with the little booger...
So, I asked her to get another one (not the cheapest one this time). So we did that. I put that one together, and tried to use it. That one leaked too! Turns out, I was learning the difference between normal threads and pipe threads (i.e., you can tighten normal threads quite a bit before they break. But pipe threads...). Then, after all that, I found our other adapter (that actually works) underneath some sandpaper. Just lying there. :evil:

,the bottle gets stuck on the launcher! Obviously, you will get fairly wet when you do get the little booger off. Then, you try putting some oil on the launch tube. But that makes it even worse! Now it comes off while you're still pressurizing!"

Then, I ran out of time, and decided to focus mainly on my best event. Sorry for the rant... Anyway, I think I got about 10 seconds (total) at the competition. But I could be off by +/- 5 s.

I'm completly sorry I didn't see this earlier. I believe I can help you a lot. (Click to Show Hidden Text)

For the bottle scratches, I believe that anything that might possibly comprimise the structual integrity of the bottle can be called out by the judge, and possibly get you DQed.
But on the other hand, it's difficult to replicate rocket results when you switch bottles. This is really a question up to decide on. Would you call out the bottle because of the scratch? or do you think that a scratch could weaken the bottle? if so, then I suggest that you replace your bottle with an Identical bottle, but make sure that you practice with this new bottle if you change it. 

For the labels, I think all judges look for is the "Carbonated Beverage" label, and sometimes a rough corrolation between bottle and label. What I mean, is that they can see if you used a 2 liter coke label for a 1 liter bottle and so on so forth.

If you are using duct tape to attach fins, I suggest that you use the least amount possible, or switch to packaging tape. Attaching fins is really the only place where you should use duct tape. If you have it anywhere else on the rocket, you should switch to packaging tape for weight reduction. If you can, even try packaging tape on the fins, but test to see if it's strong enough to hold them in place before you compete. 
The materials you use on your fins seems a bit iffy though. Balsa is a bad material for rockets in general, and I'm glad you noticed that. Foam board might work, but I have a better, weight friendly solution you should maybe check out. I suggest you get Corrugated Plastic boards, and 0.007 inch plastic film to make a sort of hybrid material fin design. 

My design consists of a Trapezoid shaped fin, made out of a parallelogram shaped piece of corrugated plastic in the front (make sure the holes are parallel to the leading edge) 
and a triangle of flimsy plastic film on the back. The film is pulled taut from being taped between the bottle and the corrugated plastic leading edge. once you have this down, I would pinch the front of the corrugated plastic into a point for better aerodynamics (hence why I suggest that the holes be parallel to the leading edge.) Then tape this onto the bottle. 

since I don't know the overall design of your rocket, I suggest that you play around with this design, and work out which variation of this design works best on your rocket. 

Good luck at nationals, and happy flying!

Thanks, Fanglin! That helps a lot!
I'm not sure I understand your fin design, though.
Would you mind posting a picture of it?

-NeBH