Water Rocket Forum

boondocksjp wrote:thanks for all the info. I didn't know if it should fly straight for awhile, and adding fins would just make it better. I guess it's time for more R&D huh?
Going to try fins first, then nose weight.
I appreciate all the 411

Most bottles have the thickest plastic where the cap screws on because they need the thick plastic for the threads and the neck where you grab the bottle. This makes a plain bottle "tail-heavy" right from the start. You really need fins because the bottle in flight will try and turn around so the heavy part is at the front and that's why they don't make good rockets without modifications. You can see what's going on with the rocket by just throwing it and seeing how it behaves. If you toss it like a dart and it flies straight and true then you know it should fly well under thrust.

Your right, I get teased a lot because if I'm driving and get lost, I'll stop for directions. But why sit there and waste time, find somebody who knows.
Sounds like you've all done this before, ha. ha. Before you get too bored giving me directions, one more thing. My next set up, after I get the quick connect to fly properly, will be a simple 2 liter (upside down) on maybe a cable release. Now from what I see, will these fly better with no fins on?
Thanks all............................boondocksjp

boondocksjp wrote:Your right, I get teased a lot because if I'm driving and get lost, I'll stop for directions. But why sit there and waste time, find somebody who knows.
Sounds like you've all done this before, ha. ha. Before you get too bored giving me directions, one more thing. My next set up, after I get the quick connect to fly properly, will be a simple 2 liter (upside down) on maybe a cable release. Now from what I see, will these fly better with no fins on?
Thanks all............................boondocksjp

In theory it should fly better but I don't think it does if you test this theory. May I ask why you have dislike of fins? They are easy to make. I cut plastic paperwork binders into fins and tape them with box packaging tape to the bottles. Easy. A second nice design is a circle fin. Also easy and makes the bottle looks futuristic.

Andromeda wrote:

boondocksjp wrote:Your right, I get teased a lot because if I'm driving and get lost, I'll stop for directions. But why sit there and waste time, find somebody who knows.
Sounds like you've all done this before, ha. ha. Before you get too bored giving me directions, one more thing. My next set up, after I get the quick connect to fly properly, will be a simple 2 liter (upside down) on maybe a cable release. Now from what I see, will these fly better with no fins on?
Thanks all............................boondocksjp

In theory it should fly better but I don't think it does if you test this theory. May I ask why you have dislike of fins? They are easy to make. I cut plastic paperwork binders into fins and tape them with box packaging tape to the bottles. Easy. A second nice design is a circle fin. Also easy and makes the bottle looks futuristic.

What is a circle fin?

Is it like a hoop fin or skirt fin which is a ring that is connected to the rocket with struts and is concentric to the centerline of the rocket, or do you mean the fins are small circular tubes connected directly to the rocket where fins normally would go?

your bottle will arc if you have a nozzle to restrict the flow i had single unmodified bottles going straight with cork in bottle launcher just made screw on nozzle for it & now bottle arcs.

Bicky 51 wrote:your bottle will arc if you have a nozzle to restrict the flow i had single unmodified bottles going straight with cork in bottle launcher just made screw on nozzle for it & now bottle arcs.

That's logical because too small nozzle gives too little thrust and rocket is unstable so it would arc.