Strobe rockets

[keepkool79]

http://i17.photobucket.com/albums/b99/keepkool79/DSC00535.jpg

I have not seen anything on the awesome rockets so I decided to start a new thread. I recently bought 4lb strobe rocket tooling and am now ready to get started. The reason that I have not yet made one is all the prep work required. The chemicals for the strobe mix must be ball milled. This is a pain. For those that are not familiar with the comp it is:

Ammonium Percholorate- Must be Ball milled

Mg/200 mesh- Ball milled with steel ball bearings

Barium Sulfate- As fine as possible

Potassium Dichromate- Ball milled

This comp is very sensitive to shock so the chems need to be milled separately. I need to get extra jars for my mill. Once the comp is ready you press the rocket with whistle mix first, than strobe mix, and than, back to whistle. If anyone has experience with these rockets please post. I need all the help I can get.

Thanks,

The pic is of my 4lb strobe tooling. It is from wolterspyrotools. He is great. The tools are truely a work of art. I have bought tools from skylighter and pyrotools and they do not even come close to wolters. If you have it, pay the extra money, it is well worth it.

[FrankRizzo]

Oooh! Those be Wolter tools all right Beautiful!

 

Would you mind measuring the dimensions of the tooling? I've got the baby-brother version (1lb) that I'll post dimensions for when I get home later tonight.

 

I usually coffee mill my AP, barium sulfate, and dichromate; ball-milling seems to be unnecessary. Mill the sulfate and dichromate together to minimize dichromate dust exposure (use a respirator though), and mill the AP separately. I usually coffee mill all three of those components together, but a recent post on rec.pyro seems to indicate potential decomposition catalyst behavior from the dichromate on the AP. Likely, you will need to ball mill your magnalium though. You can try using the mesh you currently have, but you do want a fast strobe reaction, so getting that magnalium down to size is a good idea. 1-percent copper oxide can be mixed in as well to speed up the strobe reaction if you have probs.

 

Also, if you granulate your comp through window-screen like LaDuke (I suggest you do), your increment size will be 3tbsp, which corresponds to ~.75" at the required loading pressure. Don't use any more than that, or your rammers will get stuck.

[keepkool79]

You said that my MGAL that I have will work. That is what is called for in the AFN video and I also talked to John Steiburg, he also said I needed 200 mesh. What are you using? I have differnt MGAL that I use for red, green, and yellow rockets that I could use but 200 is whats called for. I wanted to try using something a little finer to avoid ball milling, maby 325 mesh but I am not sure if it will work. Also, do you use any mg. in your rockets? Everything that I read said it speeds it up.

 

I will measure the tooling soon. Sorry, I am busy but in the next day or two I will measure them.

Thanks,

[FrankRizzo]

The finer you mill the magnalium (MGAL), the faster the strobe rate will be; you want *at least* 200 mesh. I'm pretty sure LaDuke and Steinberg *start* with -200 mesh, and mill it down further to 300-500. I use -325 mesh magnalium that I purchased from the chemical barn last year...works great. So, if you have some, use it And no, I don't use any straight Mg.

 

The worst that will happen if your magnalium isn't fine enough is that the rocket will come back down to the ground while strobing. If it's too fine, you get a nice boom. It's not an exact science, and you'll have to play around to get the effect you want.

 

So, find McMurray's <8hr whistle mix article and get cracking..err..strobing! <--- Oh, and use mineral oil with naptha as the solvent...it's soo much easier than melting the damn vaseline.

[FrankRizzo]

Well, I've misplaced my caliper somewhere, so I probably won't get the dimensions of my 1lb tooling posted until this weekend.

[keepkool79]

Well, I was a little worried about starting to make strobe rockets with my 4lb tooling. Luckily, I just got a new set of tooling. The tooling is a 2lb universal spindle. It is a little longer then a standard strobe spindle and a little shorter then a bp spindle also a little thicker. The tooling is awesome, I can make bp, LWS, hybrid, strobe and colored mgal rockets all with the same spindle.

So I mixed up a batch of strobe mix and pressed the rocket at the required 8000 pounds of force. I was so very excited. I lit the fuse, got back 20 feet, covered my ears, and booooooooom!!!!! I have made 3 inch aerial salutes with over a 100 grams of flash and this was even louder then that. It almost knocked me on my ass. I can't imagine what the 4lb rocket would have been like. I am kind of glad it happened, it gave me a new found respect for those things. I talked to Mr. Steve La Duke and he gave me some advise. I have to wait till the next open shoot to press one up though, can't wait. Anyone that has made these most impressive rockets, please give me any advise you can.

[aquaman]

Sounds like you had a pretty nice cato, too bad you didn't video tape it. Catos are aways fun to watch. That's why i like rockets they're cool if they actually work and they're cool if they cato.

 

Catos can be annoying though. Try making a thicker rocket case. And if that doesn't work try a wider nozzel. I know you're limited to the 2lb and the 4lb tooling but try to make the nozel bigger so that all those gases have a place to go. The last thing I can think of right now is to try to slow down the strobe composition. I don't know how to go about doing this so I would hope that a thicker case works.

[FrankRizzo]

Well, I was a little worried about starting to make strobe rockets with my 4lb tooling. Luckily, I just got a new set of tooling. The tooling is a 2lb universal spindle. It is a little longer then a standard strobe spindle and a little shorter then a bp spindle also a little thicker. The tooling is awesome, I can make bp, LWS, hybrid, strobe and colored mgal rockets all with the same spindle.

    So I mixed up a batch of strobe mix and pressed the rocket at the required 8000 pounds of force. I was so very excited. I lit the fuse, got back 20 feet, covered my ears, and booooooooom!!!!! I have made 3 inch aerial salutes with over a 100 grams of flash and this was even louder then that. It almost knocked me on my ass. I can't imagine what the 4lb rocket would have been like. I am kind of glad it happened, it gave me a new found respect for those things. I talked to Mr. Steve La Duke and he gave me some advise. I have to wait till the next open shoot to press one up though, can't wait. Anyone that has made these most impressive rockets, please give me any advise you can.

If you use the universal spindle, you need to add an extra part of vaseline to your whistle mix to slow it down a bit, sometimes even 2 if you're using the old Swedish perc.

 

I know what you mean about that blast wave from a strobe rocket CATO. I was down on the rocket line at last year's PGI convention, when Jim B. nonchalantly strolled down to one of the racks and loaded up one of his 4lb'ers. A few of us were standing around about 30-40ft away, talking about end burners when the damn rocket CATO'd on the rack. It made a brief whistling sound and then KABOOM! Everyone was caught off guard, and I swear my heart skipped a beat when that fucker went. We were all in shock for a few seconds afterward...good times :-)

 

I still haven't managed to track down my caliper to measure the holes in the rammers for my 1lb tooling. I'll bring the set to the metal shop on campus and just measure 'em there.

 

Any chance I could get the measurements for the holes in your rammers? For length, I'm assuming that the "A" rammer is probably ~10" and the "B" is ~8?

 

Also, your calculation, and Passfire's loading pressure calculator are basically correct; your calculation is slightly off because of rounding.

 

X * (pi * (piston radius)^2) = Y

Y / (pi *(tooling radius)^2) = desired loading

 

so

 

X = ((desired load)*(tooling dia)^2)/(piston dia)^2

 

so

 

X = (8000*(7/8)^2)/(1.75)^2 = 6125/(1.75)^2=2000 psi gauge pressure

 

Which is what Passfire's applet says.

[Mumbles]

Might this Jim B. you refer to be Jim Biersach? I've been talking to him a bit recently. Perhaps I will have to bring this up next time he starts giving me crap about something.

[FrankRizzo]

Lol..yeah, sure is. Keep in mind that a rocket blowing up on the rack, especially a strobe rocket, is nothing new at a PGI convention. The problem was that his rockets had been fairly successful up till that point and nobody was expecting it. :-)

 

Are you a member of the PGI, Mumbles?

[TheSidewinder]

Mumbles, when you give Jim B. a ration of shit, give him one from me, too.

 

I was talking to him one of the days at the convention in the rocket shed along with Steve LaDuke. Seems I remember him saying that he had had a *few* CATO's all of a sudden. Someone else was having the same problem. I think it was the guy that made the huge ground wheels? Wonder if they ever solved the mystery...

 

Keepcool, that's a damn nice set of tooling. Good luck with it. I haven't done any strobe or whistle yet, but I can tell you that you should talk to LaDuke. He's always willing to talk shop.

 

M

[aquaman]

You said that my MGAL that I have will work. That is what is called for in the AFN video and I also talked to John Steiburg, he also said I needed 200 mesh. What are you using?

For those that are using the MgAl strobe composition: Have any of you tried the composition below? I ask because MgAl is too expensive for me.

 

Ammonium perchlorate -63

Black copper oxide -10

GE Silicone II -22

PVC -5

 

There is no MgAl so it eliminates the problem of "what mesh should my MgAl be" and the only reason that I can think of using the composition used by FrankRizzo is that it'll give a brighter strobe.

 

So is there anybody that has tried this composition of something similar?

[keepkool79]

I have been slowly working building strobe rockets. I always hear people talking about them but never got a chance to watch one in action. So, I started with my two pound universal spindle and went to work. First one blew up. It was loud as hell. I spent about three weeks thinking about what went wrong. I built up a second one and it flew perfect! I am very excited. I plan on going to the open shoot in PA at the end of April. I hope to have these strobe rockets working great every time. I am going to bring my 4lb strobe tooling to build some up at the shoot .

For anyone working with the universal spindle: I have narrowed the possible problems with my first attempt to; 1) I did not use enough hose clamps on the support sleeve, I now stack them one on top the other right to the top. 2) Not enough pressure, first rocket I used 8000psi of force. On the second I used between 8800-8900psi of force. 3) First rocket I used 4 increments of whistle mix. The second I only used 3. It still had more than enough power.

Last thing, when I mixed my strobe comp. I did not ball mill the mgal nor did I use magnesium, just straight -200 mesh mgal. For the pot. dichromate, instead of ball milling for 10 hours I just through it in my coffee grinder for about 45 sec. and it was good to go. I am not sure why some people have all the problems with this mix. I think that since the universal spindle is so much longer then a normal strobe spindle, you do not need to increase the strobe rate in any way. Just a thought.

Sorry to ramble, just very excited. Those things fly perfect!!!

Later

[Caleb51]

Without flaming me, can someone either give me a link to a site that explains what strobe rockets are/do, how to make them, et cetera. I'm relatively new, and 15, so I can't make sense of any of this. And what is a CATO?

[Mumbles]

A CATO is essentially a failed rocket. There are some different interpretations of the accronym. Usually CATO is used when it blows up on launch or soon after launch.

 

Strobe rockets are just what they sound like. They are rockets that strobe. Here is a time lapse picture :http://www.pyropage.com/Images/1996FPAG/StrobeRockets.jpg The balls are the flash phase of the strobe, and the little lines in between them is the smoulder phase when no or little light is produced.

 

For how they are produced, here is a decent description :http://www.skylighter.com/skylighter_info_pages/article.asp?Item=43 It is the 2nd or third thing down.

[Caleb51]

Yeah, I knew it was a failed rocket, but I was wondering what it stood for, if anything. So I read that skylighter formula. Do you just take that mix and stuff it into a tube? Where do you put the fuse? Do you have to make a nozzel?

[Mumbles]

You use strobe tooling. That takes care of the nozzle, and core, and all that.

[keepkool79]

It is awesome that you are interested in strobe rockets. They are one of the most spectacular and sad to say most difficult rockets to see and build. A real quick run down, first you need special tooling, I have a pic of the tooling at the top of this thread. Next, the comp, it is a 3 part fuel system, I use 3-4 increments of whistle fuel, then strobe fuel to about 1/8 inch over the spindle, then more whistle fuel the rest of the way. That is the basic run down.

These rockets are very powerful and must be made on a press with a blast shield. When one blew up near me it almost knocked me on my ass. I would say that you should build black powder rockets for a while, then whistle rockets, then you should be ready for strobe rockets. But again, this is a VERY powerful and sensitive mix, be VERY CAREFUL!

Good luck,

[Mumbles]

I'm not completely familiar with strobe rockets, but is the whistle always included? I've only heard about this for those hybrid rockets.

[FrankRizzo]

Mumbles,

 

With Steve LaDuke's white strobe rockets, the whistle mix is what provides the thrust for the rocket. The strobe is basically just a garnishment, although it does provide some thrust. The additional pressing of whistle mix is to provide a bulkhead/delay without having to use clay and a passfire hole.

 

Here are a few videos of some white strobe rockets with a weak/damp salicylate whistle mix:

 

1lb. strobe w/report

 

4lb. strobe - plain

[Pyrohawk]

Caleb: CATO means Catastrophe At Take Off.

[FrankRizzo]

Yet another not-so-successful 4lb strobe rocket launch:

 

http://rapidshare.de/files/17538028/4lb_Strobe.avi.html

 

How a 4lb strobe is *supposed* to perform:

 

http://rapidshare.de/files/17538409/4_strobe.mov.html

[Givat]

In my opinion the less Hz strobing you had in your rocket is better looking, so you only got the "less thrust" problem to fix.

 

p.s.

Maybe it's only me, but I heard Santa laughing at the background in your movie

[FrankRizzo]

p.s.

Maybe it's only me, but I heard Santa laughing at the background in your movie 

 

LOL...yeah, that'd be my buddy. He was surprised at the caliber of report that I'd stuck on that rocket.

[keepkool79]

I am working on 4lb strobe rockets. I made one up and it blew. Anyone that’s made a 4lb strobe please give me info. I would like to know things like increment size, how many increments of whistle mix and what type of whistle fuel you use (76-23-1) ect.....

Thanks