Rocket Design help

[PyroMan16]

Anybody see any issues with this design. I've never tried putting a payload on a rocket and thought i would give it a try.

 

rocket_2.bmp

 

Fuel: Granulated green mix BP (no ball mill)

Plugs: 50/50 mix of Bentonite and Kyanite

Ignition: Green Visco fuse from Skylighter

Core: 4-5mm drill bit

Homemade paper tubing

Delay: Really slow sugar/KN03 mix with a bit of baking soda to slow it down more.

Break charge: just some loose BP poured in, maybe with a little FP???

 

Any help is appreciated!

[Aneantis]

You need to drill a hole in your top endcap and then ram some meal in there.

 

Edited September 7, 2009 by Aneantis

[Seymour]

In my experience even greenmix Black powder is way too fast for coreburners, and will cause reliable catos. I know that people have had success with them (presumably by using much slower burning charcoals than me), and if you are one of those people, then that is good. However if this is your first rocket with this fuel and a core, don't be surprised if you have a salute on a stick.

 

I would at least change the fuel to 70% Potassium nitrate, 20% Charcoal and 10% sulfur, and perhaps add even more charcoal.

 

Getting the delay time right can take a bit of trial and error, especially with something as unreliable as KN/SU/NaHCO3. I'd stick with just a bit of BP or flash for initial tests, as it gives a visual que of when the delay has burned through, but I'd leave it at that for now. If there is a fire risk in your area which might make a rocket landing in some scrub with the delay still transferring fire a bad idea, perhaps you should static test your first few of these motors.

[Aneantis]

When willow greenpowder is used a core design will cato. But on the other hand when BBQ-c is used you can core all you want.

[Mumbles]

You have the right idea. I would get the rockets flying reliably before trying to attach headers though. It seems you're unsure on their construction, so some testers are really needed. It's dangerous and not very smart to jump in over your head in this case.

 

I don't think you need additional visco coming from the delay into the heading. I also don't agree that you need to ram BP or green meal in there. Most people get away with just filling in the top with granulated BP. A couple of sticks of black match would work fine too.

 

If you want to mix it up, glitter mix or willow mix is really attractive as a delay layer.

[PyroMan16]

K. The charcoal is that crap from skylighter so its slow enough. I am sure of the constuction of the actual motor just not the header. I have flown a couple rockets succesfully off this bp so I`m confident it will work, I`m just scarred of the delay being to short or to long ad I would do more static tests but I live in between a lot of houses and I've got these dick that live behind me that called the cops on me yesterday cause I lite about half a gram of BP under my deck so then I sat in a police station for an hour trying to explain that I`m not a terrorist! Dang neighbors

[dagabu]

K. The charcoal is that crap from skylighter so its slow enough. I am sure of the constuction of the actual motor just not the header. I have flown a couple rockets succesfully off this bp so I`m confident it will work, I`m just scarred of the delay being to short or to long ad I would do more static tests but I live in between a lot of houses and I've got these dick that live behind me that called the cops on me yesterday cause I lite about half a gram of BP under my deck so then I sat in a police station for an hour trying to explain that I`m not a terrorist! Dang neighbors

 

OUCH!!

 

I think you need to address the legal issues with the police chief and find out what the laws in your area really are. You can make, store and use BP for sporting purposes (Federal BATFE) but your state and local laws may be far different.

 

As far as the motor goes, I think almost everyone that has ever sent up a core burner will counter that assumption that BP will make a CATO. Every tube has its limits and if it CATOs and the nozzle stays in, you probably need to add charcoal to get the mix right for your BP.

 

Mill Spec 7 BP is very energetic and can be used in core burners with and additional 20% charcoal (hardwood).

 

As far as the delay goes, i sent up two core burners with headings two weeks ago at a meet and had round trips with both and a good 6 seconds of smoking on the ground before setting the headers off. That was WAY to much delay!!.

 

You will have to test your delay by timing it in rockets with different amounts of delay rammed on top. Start with 1/8", that gives a good half second if using Crys 6. The corrected rocket I static fired last night had 1/4" of my regular fuel with 25% added charcoal mixed in and it gave me just under one second of delay.

 

I like to drill my passfire hole right in the center if I am using a canister shell with a visco time fuse so that it aligns up with the fuse, no BP is needed for the visco since the motor is burning plenty hot. If I have a ball shell or some other heading, I drill two holes on opposite sides right next to the tube wall and sprinkle just a dusting of Mill 7 in the holes, more if I want a separation from the rocket.

 

[EDIT] You will definitely want to increase your comp over the spindle to at lease the spindle to wall distance so your delay doesnt burn up when the rocket is under power, it should be burning in the coast stage.

Edited September 8, 2009 by dagabu

[PyroMan16]

Ya I know its pretty rough! Whats funny thou is that the cop printed the codes up and he couldn't even tell me if its legal or not because he didn't understand that i'm not in my basement make pipe bombs and blowing stuff up that I'm actually participating in a lagit sport(experimental rocketry). So I've now talked to 2 cops(one being the head one) and they still wont give me a strait up answer on if it is legal to own/have chemicals like KN03 and sulfur, if its legal to make them and if its legal to fire them!

 

Thanks for the advice. For the delay I think I'll just take some off my already slow BP, say like 10g. and add maybe 2.5-3.5g. charcoal and mess around with. Then once I find a good mix I'll do little tests like you explained to find the ideal delay.

 

I've already made one rocket exactly like in the pic above, its 3in long and has a core of about 2-3cm past the nozzel so i hope it doesn't CATO!

[dagabu]

Ya I know its pretty rough! Whats funny thou is that the cop printed the codes up and he couldn't even tell me if its legal or not because he didn't understand that i'm not in my basement make pipe bombs and blowing stuff up that I'm actually participating in a lagit sport(experimental rocketry). So I've now talked to 2 cops(one being the head one) and they still wont give me a strait up answer on if it is legal to own/have chemicals like KN03 and sulfur, if its legal to make them and if its legal to fire them!

 

Thanks for the advice. For the delay I think I'll just take some off my already slow BP, say like 10g. and add maybe 2.5-3.5g. charcoal and mess around with. Then once I find a good mix I'll do little tests like you explained to find the ideal delay.

 

I've already made one rocket exactly like in the pic above, its 3in long and has a core of about 2-3cm past the nozzel so i hope it doesn't CATO!

 

The CATO will be all about your nozzle diameter. To large and the rocket is slow, to small... well we don't call them b***s on a stick for nothin!