Strobe rockets

[invisibleworld]

Back @ Frank: No Ive had it happen before when making some wierd white strobe stars, turned out then burned green, they expanded and swelled up. Never had it happen with anyother star comp. Maybe the boric acid slowed it down, na not as bad as it is, shit cant even keep itself burning.

 

Mumbles ive made blue strobe before but never used it properly, in a rocket. This is a video of a rocket I made with 4oz bp tooling, just straight strobe with a nozzle. Dont think Ill do it again though, I just hand pressed it in(with a hammer) and it clogged all up into my tooling and took me awhile to clean.

 

http://i108.photobucket.com/albums/n3/psyc...22/S4020734.jpg

 

http://s108.photobucket.com/albums/n3/psyc...nt=S4020735.flv

 

invisibleworld what kind of tooling did you use for the 4oz? Not sure if thats a typo or Ive just never heard of P/B tooling.

Yes, it is a mess. It was Black Powder tooling, and like I said before, it is a gooy slop that blows out your tubes when pressing due to the hydrolic effect pushing in all direction instead of mainly down with a dry compound. I had to keep cleaning out the hole in my ram and be real carefull to press lightly. That is why I let it cure most of the way and then scraped it acroos a screan to granulate it. when it dried all the way it was a lot easier to press and mess with. Good Luck

[psyco_1322]

325 too fine? .... maybeeeeee.

 

 

Did you use a nozzle in that strobe? Or was it made like a normal strobe with particle whistle?

[Mumbles]

Frank, usually I agree with you on most things, but I don't really see how replacing half the barium sulfate with strontium sulfate would make anything but a mediocre pink. Perhaps it appears white. You know more about rockets than I, so I will believe you on this one. From hanging around some rather prolific rocket builders, I would have imagined this would have come up though.

[psyco_1322]

Ya but I think the blinding white from the burning magnalium would out way the light pink, you might notice a bit of difference side by side but not individually. But I dont know.

[FrankRizzo]

Frank, usually I agree with you on most things, but I don't really see how replacing half the barium sulfate with strontium sulfate would make anything but a mediocre pink.  Perhaps it appears white.  You know more about rockets than I, so I will believe you on this one.  From hanging around some rather prolific rocket builders, I would have imagined this would have come up though.

I'm sorry, maybe I wasn't as specific as I should have been. The other half is still barium sulfate, so you have a 50/50 mix at the same total percentage of barium sulfate called-for in the formula. The red and green colors combine and trick your eye into seeing white. I got this tip from the same strobe guy (Ken), and it works beautifully.

[Sambo]

I've made a few 3lb strobes recently, it has taken a few attempts to get right but I've eventually got there. Click me

It strobed as you can see the from the smoke tail but i got no popping sound, what you hear is the wind playing tricks I believe.

Here is another one, definate strobe smoke tail but again no popping. I think the wind caught this one sending it into the moutain..

 

My question is does anyone know why I get strobing but no sound?

[FREAKYDUTCHMEN]

How long was the core of the strobe part?

[Sambo]

The motor had 2.5" whistle and 1.25" strobe on a 3.5" spindle, so strobe was cored 1". I have to use more whistle as the benzoate whistle just doesn't have the kick of salicylate. I also found that my strobe seems to burn quite slowly and provide little/no extra thrust, I had a few come back down still strobing whilst using the dimensions from SLD strobe rockets; this is why I used more whistle and less strobe.

[dagabu]

Mumbles ive made blue strobe before but never used it properly, in a rocket. This is a video of a rocket I made with 4oz bp tooling, just straight strobe with a nozzle. Dont think Ill do it again though, I just hand pressed it in(with a hammer) and it clogged all up into my tooling and took me awhile to clean.

 

I do so hope you were just pushing down and not pounding! Please explain how you compacted this comp so the noobs don't look at this and say, "Hey, psyco did it and I can too!", followed by a boom and three missing fingers.

[dagabu]

As for lifting amount, you'd have to ask someone else. I'd say at least a 4" ball shells so 300g or so.

 

I don't think I saw a ball shell on a strobe at PGI, Ill look at the video. Most have a small report at apogee to disassemble the tube and stick so that there are no lawn darts and to see what height it was. I'm waiting for my SLD tooling for 1# hybrids.

[FREAKYDUTCHMEN]

Come on you're interrupting a discussion with quoting 2 year old messages.

 

Sambo, how longer the strobecore is, the better. If I were you I'd use CuOCl as the catalyst.

[Mumbles]

Dagabu may be able to correct me here, but strobe isn't supposed to provide any thrust. I don't know why you're using it in the core portion. The actual strobe thickness above the spindle is good, but I think you may just be wasting strobe mix, and losing out on potential thrust. Everyone I've talked to gives me the impression that whistle is used for the spindle portion, and strobe as essentially the delay portion. I know some like more whistle on top of the strobe to give a little something extra before the header goes off.

[psyco_1322]

I do so hope you were just pushing down and not pounding! Please explain how you compacted this comp so the noobs don't look at this and say, "Hey, psyco did it and I can too!", followed by a boom and three missing fingers.

 

Nope, I beat that shit into the tube. But seriously I did "lightly" tamp it in will a rubber mallet. As liquid as its state is, you can't really get it to consolidate, it just squishes out ever where and turns into a mess. So for all the noobs DON'T DO THAT...its a mess and not worth your time.

 

Did you by chance see and really big bottle of liquid on rockets while you were at the convention?

 

 

Mumbles,

 

How so wrong you are Yay! I get to correct the smart guy

 

Strobe rockets normally have at most half the core as strobe fuel. The rest is whistle usually. Some have to tweak these ratios to keep the rocket in the air. The reason most peoples strobe come to the ground is that the strobe portion over the spindle is too thick... it takes just a tad bit over the spindle, about 1/8 - 1/4". Anymore and they will be raining to the ground. The strobe core is actually what is responsible for the loud popping noise you hear. More surface area to strobe, louder the pop gets. If you just pressed it in as a delay like you're thinking you would get the strobe look, but no noise. Plus the core section is enough to shoot a nice sized blast of fire out the back of the engine, giving a more defined effect. If you ever notice some peoples strobe rockets on video look almost like dashes of light instead of spots...that's why. I think the reason everyone puts whistle over the strobe is because that's what the paper that comes with Wolter's tooling says, which is SLD's drawling. I find it rather annoying to hear whistle come back on after a nice strobe. It's not like it provides any more coasting thrust than the strobe does. One could leave it out or replace it with something a little more pretty.

Edited September 13, 2009 by psyco_1322

[dagabu]

Did you by chance see and really big bottle of liquid on rockets while you were at the convention?

 

Yes, a club member put a few together and I got to sit down with him and go over their construction with him. I haven't made any yet but they look fun! They are called Lamparies (SP) and usually use Methyl or Ethyl alcohol in them.

 

Sorry for interrupting your conversation but it was midnight and I was tired .

 

I just made some GE Silicone ll blue strobe mix and set it in short tubes for display tonight, If it works I will try it in a rocket. I have yet to get my tooling and there is no time tonight for a conversation with Steve so I will have to address the whistle issue with him tomorrow after work.

 

[EDIT]

 

Strobe was WAY fast, good color, good light, still not fully cured, we will see what they look like tomorrow night. Pretty blue, make me happy.

Edited September 14, 2009 by dagabu

[FrankRizzo]

Here's the table Steve made, which Rich W. provides with his tooling:

 

Rocket Size Whistle Mix Strobe Mix

3/4"-(1lb) 1.250 1.500

7/8"-(2lb) 1.365 2.000

1" - (3lb) 1.565 2.000

4" - (4lb) 2.565 2.500

[Sambo]

Yesterday I turned a new spindle up, overall length was 4.5". This gave me enough length to put my 2.5" whistle and 2" strobe with 1/4" strobe above spindle... Nice tail but still no popping sound

 

On the whistle over strobe thing - I believe the whistle compacts better than the strobe fuel acting as a bulkhead and a delay, I may be wrong here though. Also it is a non-nitrate composition so is fine in contact with the ap and since you already have whistle made its an easy delay.

 

I would use copper oxychloride but I cant find a supplier in the uk, there are a few in the US but shipping is a killer.

[FREAKYDUTCHMEN]

Did you make your strobe mix with vasoline, mineral oil or NC? Some will just not pop with NC laquer.

[Sambo]

It was made with vasoline, I read about NC keeping the strobe burning so it wouldn't flash between the smoulder and burning states.

[TYRONEEZEKIEL]

@ FrankRizzo

 

Did you ever get the dimensions of your tooling?

[Sambo]

Here are the dimensions for 3/4" to 1.25" strobes.

[FREAKYDUTCHMEN]

What's the mesh size of your MgAl?

[Sambo]

I use 20 parts 200-250# and 5 parts 120-180#.

All other chems are ball milled to flour-like consistency.

[FREAKYDUTCHMEN]

The last two things I can think of is your bariumsulphate isn't as good as it should be. I've read some about that on passfire.

The other thing is that it maybe isn't mixed well enough.

 

I use finer mesh MgAl, 270 mesh 25 parts. To speed up the burnrate up to 50% ballmilled mgal. So 12 parts 270 mesh and 13 part ballmilled (-325 mesh or so) The last one almost sounds like a helicopter.

[Sambo]

That was my thought, I'll try to get some other barium sulphate and see how that goes.

I mixed it up well, this shouldn't be a problem. I firstly tried with 200-325# mgal, ~ 80% 250-325, it just burnt continuously and failed to strobe. This is why I'm now using the coarser stuff. Its just really odd that the smoke tail can be seen and is consistent but i just get no noise. Ill try it on a longer spindle again with 2.5" strobe comp and see how that goes.

[TrueBluePyro]

For the strobe, could you use 'Bleser #26'

 

Barium Nitrate 51

Sulfur 19

Magnalium, granular, -100 mesh 18

Potassium Nitrate 7

Dextrin 5

 

Or does it have to be a AP based strobe?

 

Also, what is a good whistle fuel for 5/8" rockets?

 

Thanks

-Will

Edited September 16, 2009 by TrueBluePyro