bottle rocket with standard fast milled blackpowder

[insutama]

I have the bottle rocket tooling from pyrocreations and it seems whenever i make a rocket with the 3" 1/4" tubes it burns so fast i have seen other peoples bottle rockets they made with the same tooling on youtube and it seems like there rockets go higher and burn longer is this maybe because i am using normal black powder 75:15:10 would it help if i used the rocket fuel mix say 60:30:10 do you think my rocket would go higher. I have been putting little plastic 1" shells with black powder a bit of flash and cut up star peices on the end of the rocket for the report but it seems like everything happens so fast after the fuse is lit. as soon as the rocket takes off its like 2 seconds later the shell bursts so im thinking this is because my BP is too hot its really fast bp i milled it for 4hrs and granulated it with alcohol so it burns incredibly fast. What do you guys think ?

[gregh]

Do you have a camera? I go back and watch things in slow motion and even step motion. It is very helpful because like you said, it all happens very quick!

[Mumbles]

Are you using any sort of delay on the shell header? In some cases a fuse is used on the shell, or a slower burning delay is pressed above the spindle to give the rocket more time to coast upwards and delay the header until closer to the apex. It can also be a place to add an effect like glitter, or metal in the delay, to give a little something extra to the rocket. It also makes it easier to track.

[Arthur]

Small rockets need a short coasting time after the charge has burned out, try half to one second as a start. The motor stops but the rocket still flies til it runs out of energy, that's the point at which the header should operate.

[insutama]

i was using a small piece of visco for my delay but maybe it wasn't big enough it was basically just big enough to go the middle of the shell id say about 1/2". Ill look into different delay mixes and try that out thanks guys.

[schroedinger]

In my bottle rockets i use 1/4" of zink spreader formula as a delay. They burst at about 70 feet with a 1" report.

[insutama]

With my tooling I only get about 1/2" of room from the top of the spindle to the top of the tube and I have been leaving a little space so the shell and fuse can fit on does this sound normal or do I need bigger tubes?

 

I'm at work right now when I get home I'll take some pictures to help show what I mean I'll be home sometime tomorrow

Edited June 18, 2015 by insutama

[nater]

I have more than 1/2" of extra space in my 1/4" kit, but it is not a lot. I use various fuels in the core and a slower delay. The header just gets fused with a stick of black match so it does not need much room anyway.

 

Even with slow propellants, these little bottle rockets are fast. If you are truly getting 2 seconds of delay from the core burning out to your header, that sounds about right. If you were being figurative when you say "like 2 seconds", a little longer delay would be good.

[insutama]

I'll record a video when I get home and let you all tell me ur opinion but I actually ment 2 seconds literally but I'm talking about from when the rocket lights to when the burst pops Edited June 18, 2015 by insutama

[schroedinger]

If your delay is to short and you do not have much space, you also could think about adding 2 mm of glusatz as delay.

[insutama]

ok so here are the vids and pictures. the first video is just a tiny bit of flash at the end of the tube then hotglued the second is with a 1" shell filled with 2 grams flash i used a little bit longer piece of visco as the delay and it seems to have worked better but anyway tell me what you guys think is this kind of delay normal or is it still quick ?

 

 

[mikeee]

If you have a tube support you might be able to ram the fuel grain at a little higher pressure. This should increase your burn time, you could also ram the fuel all of the way to the top of the tube to gain a little more burn time. With a tube that size you are somewhat limited to how much performance you can attain. But they are fun to play with. :-)

[insutama]

if i ram it to the very top of the tube its hard to get the shell on because there is a little nipple on the shell were the fuse hole is so normally i leave a 1/8th of a inch at the top of the tube so the shell fits on flush to the tube

[nater]

Those looked like normal bottle rockets. What performance are you expecting or striving for out of them?

[insutama]

i was just wondering if its normal for them to burn so fast with the report going off that soon but i think i figured it out thanks to you guys.

[nater]

I like to make these tiny rockets, but I rarely film them. Here is an old video of my early SBRs that I have posted here a few times in the past. You can see the thrust phase and delay are all pretty short, similar to a commercial bottle rocket.

 

 

[coogan1997]

Yep, i agree with nater. Those look like pretty nice bottle rockets to me.

[insutama]

i really like the silver fish rocket, they look like go getters, i would love to learn how to make them and thanks for clearing that up for me

Edited June 19, 2015 by insutama

[nater]

The silver fish header is just a bundle of flying fish fuse trimmed about an inch long and primed on one end. I made little bag headers around a 3/4" dowel. Use a little of your BP fuel as burst, stack the fuse on top and either tie or fold the top of the bag shut.

[insutama]

nice i wish i could get flying fish fuse here in canada but just like everything else i cant.