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Old Jun 24, 2005, 12:58 PM
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Question
DIY rocket motor ?? sodium chlorate

Hi just wondering whether or not any one has had any experience with making there own motors? i have been into rocketary for a few years and have used all engines up to "D" sizes but when the price keeps on rising when your paying 5 quid for a pack of 3 C size motors the becomes a point when you think what is the point?

I have beeen reading around about saltpeter motors, amd essentially sodium chlorate is the same thing you jsut test out differnt ratio mixes with sugar untill you find the right mixture?

has any one tryed this before and what will i need to make them procedure, safety, parts and essentially how much thrust will one kick out when i light it?
as i am interested in going into the slightly larger moddles i.e. E-H engines but do not want to be paying 20 quid for a motor every flight

cheers aaron
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Old Jun 24, 2005, 01:29 PM
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I forgot too add is sodium chlorate more unstable than salt peter or doesnt that metter when casting a motor?
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Old Jun 24, 2005, 01:43 PM
Turn down for what?
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Joined Feb 2004
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Do yourself a favor. Go out and do a bunch of research on this before attempting it. And this is probably the wrong place to be asking. There are far to few people on this little portion of RC groups. I have been flying model and high power rockets since 1996, and I have not even seen this kind of thing. I don't know where the proper place to get this information is, but it must be out there.

Good luck, and please be safe.

Ryan
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Old Jun 24, 2005, 11:57 PM
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I did some "unauthorized" experiments back in the high school chemistry lab with sugar and potassium perchlorate. I'm lucky I graduated in 1979 because in today's post 9-11 environment, I'd probably get 30 years! I'm also lucky I didn't get hurt.

An alternative to consider is Aerotech reloadable motor systems. I have reload casings in E through J sizes and I really like them. They also come is D, and I believe some C sizes as well. May be a little less expensive than Estes, but alot safer than home made motors fueled with chlorates and perchlorates..

Here's a link to Rocketry Online, one of the best websites for all forms of rocketry.

http://www.rocketryonline.com/


Rob
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Old Jun 25, 2005, 02:31 AM
ScuseMeWhileIKissTheSky
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Chlorates are very unstable. Mixtures containing chlorates are sensitive to shock, friction, and static electricity which means it is easy for them to go off accidentally. Chlorates are bad news. Stay away from them.

Perchlorates are less unstable, but still very dangerous and should also be avoided if you wish to maximize your chances of surviving in good health until your next launch date.

There are much safer and cheaper alternatives. Most non-commercial rocket engines that I'm aware of are made of a mixture of potassium nitrate (saltpeter) and some form of sugar - usually sucrose (table sugar). Potassium nitrate and sugar are both easily obtainable and inexpensive in most parts of the world. This fuel mixture is much less ignitable than chlorate based mixtures. It is still dangerous, as is any highly flammable substance, but I would argue that if stored properly, rocket engines made with KNO3/sugar are safer to have around than the can of gasoline for your lawn mower.

That's not the end of the story though. Making safe rocket engines encompasses alot more than using a relatively safe fuel. The casing must be strong enough, but not too strong. A casing that is too strong will just make the explosion more powerful if the rocket becomes clogged or otherwise overpressurizes. The nozzle and especially the nozzle throat must be an appropriate size. The fuel grain must have an appropriate geometry for the fuel, casing, and nozzle you're using. All of these things are interdependent and each must be taken into consideration when designing the other. For example, if you decrease the nozzle throat diameter, the pressure inside the rocket will increase, so the casing must be stronger. If all of the design parameters are not carefully balanced, your engine will either explode or fizzle.

It is, however, quite possible to make your own engines while remaining safe. The task may seem daunting, but there are several good resources out there to help. My favorite is http://www.nakka-rocketry.net. It is a very comprehensive site put together by Richard Nakka. It deals with everything from propellant formulations to nozzle design to thrust measurement to genuine rocket science theory including fancy pants equations. Safety is the highest priority in everything he does. The first section of his site is about safety and includes some great guidelines.

There are also several freely available rocket engine design programs. Most are excel spreadsheets. The Nakka site has some great ones, but my favorite is not there. It's called Grains2000 and can be found on the Australian Experimental rocketry site.
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Old Aug 02, 2005, 07:24 PM
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If you ever heard of G. Harry Stine, who I think started the old Centuri company, you may know that he had a series of articles in the old Air Trails magazine, and did talk a lot about home made rocket engines, since that was all that was available at the time. He also made a lot of mention about the dangers of home made rockets, including a number of pictures of what can happen when something goes wrong, such as a microscopic flaw in the grain. Since a lot of people in those days did things like tamp fine gunpowder into an aluminum tube casing for a motor, accidents were many, and quite a few people either lost body parts, or were killed. Thats a large measure in his starting the company, to save lifes.
He also published a number of Sci-Fi books under the name Lee J. Correy. I have most of them in my collection.
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Old Aug 03, 2005, 12:21 AM
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Chlorates are dangerous

Never mix or grind chlorates, and/or fuels together! They will react explosively
If you really must try to make your own motors, you will need to first understand the chemistry involved.
Do some research. Be it online or from a book.
You will see nice static tests of engines, but you should never see your own
All tests of any unproven design, must be carried out with the mindset that failure will occur. That the device is secured, and that if the device should fail, no harm will come to anyone, or anything. Including yourself
By the way the Estes formula is basically high sulpher black powder
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Old Aug 03, 2005, 08:49 AM
Turn down for what?
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Quote:
Originally Posted by 50+AirYears
If you ever heard of G. Harry Stine, who I think started the old Centuri company, you may know that he had a series of articles in the old Air Trails magazine, and did talk a lot about home made rocket engines, since that was all that was available at the time. He also made a lot of mention about the dangers of home made rockets, including a number of pictures of what can happen when something goes wrong, such as a microscopic flaw in the grain. Since a lot of people in those days did things like tamp fine gunpowder into an aluminum tube casing for a motor, accidents were many, and quite a few people either lost body parts, or were killed. Thats a large measure in his starting the company, to save lifes.
He also published a number of Sci-Fi books under the name Lee J. Correy. I have most of them in my collection.
G. Harry did not start Centuri. That was Lee Peister (name mispelled). G. Harry started a rocket company though. I want to say it was MRC. G. Harry also founded the NAR.

You are right about the danger of making your own stuff. I know a guy that lost a few fingers on his left hand from making ameture rockets.
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Old Aug 03, 2005, 09:12 AM
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Amazing what about 40 years does to your memory. I almost put him down as starting Estes.
I thought MRC was originally a model railroad supplier that occasionally dabbles in model aircraft. The old Model Rectifier Corporation.
That stuff is dangerous. A couple local kids just did a video based on how they actually lost parts of their hands from fireworks. Same gunpowder base as used in most model rocket motors.
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Old Aug 03, 2005, 09:20 AM
Turn down for what?
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Quote:
Originally Posted by 50+AirYears
Amazing what about 40 years does to your memory. I almost put him down as starting Estes.
I thought MRC was originally a model railroad supplier that occasionally dabbles in model aircraft. The old Model Rectifier Corporation.
That stuff is dangerous. A couple local kids just did a video based on how they actually lost parts of their hands from fireworks. Same gunpowder base as used in most model rocket motors.
Now when you say "that stuff", of course you mean "making your own motors". Pre-manufact motors are extremely safe. Model rocketry has a very good safety record.

Perhaps you are right on MRC. I know G. Harry had a company, but can't remember. Of course everyone knows his son started/runs Quest.

Ryan
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Old Aug 03, 2005, 09:51 AM
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Exactamente. Trying to make your own motors when either you know nothing about it, or worse, when you only know enough to be dangerous.
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Old Oct 01, 2005, 11:21 PM
I AM A ROCKET SCIENTIST!
Meridianville, Alabama
Joined Nov 2004
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If you are doing it to save money you are doing the wrong thing. If it is for the education, experimentation, then you have an excellent reason to do it with much research. It will be extremely difficult to make you own motor in the C, D range that is comparable to premade ones let alone cheaper. Just things to think about. Making rocket motors is a whole different ball game and should not be taken lightly or one of those "hey watch this" kinda things.
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Old Oct 02, 2005, 12:59 AM
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Maybe NAR should do a historical series and include some of the pictures Mr. Stine put in his column from Air Trails showing some of the burst casings and I think I remember even some pictures of damaged hands. Include one of his columns on proper tamping the fuel mix into the casing and how easy it is for improper tamping to leave cracks and other flaws that turn a rocket engine into a pipe bomb.
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Old Oct 03, 2005, 11:52 AM
Thanks for the Fish!
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Check out www.firefox-fx.com they have a great kit to get you going
I build all my own rocket motors
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Old Oct 05, 2005, 03:35 PM
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Check this out. If you want to make some motors this site has very good information and free motor designe software. Read all that you can! I have made several motors based on Richards software and all have worked great. Not one CATO.....

http://www.nakka-rocketry.net/index.html
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