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Propellant grain


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#1 pritch

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Posted 01 May 2004 - 04:17 PM

I've just got my full set of mesh seives from steve and im wondering what the best grain size would be for rocket propellant. I have 10 - 400 mesh and im not sure which to use. I have seen some people using meal d but is this the best?

Lots of sites such as mats just use meal and pulverone for lift but now I can press my meal into cakes and sieve it into different sizes will this produce better results?

thanks

Pritch

#2 Phoenix

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Posted 01 May 2004 - 05:38 PM

The purpose of granulating rocket propellant is to make it less dusty and easier to handle, and to make it less fluid so that it doesn't flow up around the rammer. Since the individual grains are crushed and compressed into one single grain during ramming, the starting size of them isn't really critical. It is not even necessary to granulate the propellant, it's just nicer to work with if you do. When I granulate rocket propellant, I dampen it and force it through a 2mm sieve, which is about 10 mesh.

You do not need or want hard grains for this purpose, so pressing would not be necessary. The grains need to crush when you ram them, or you'll end up with a salute. Therefore rocket propellant is granulated like pulverone, but with little or no dextrin.

#3 adamw

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Posted 01 May 2004 - 06:26 PM

Please dont confuse a rocket propellant 'grain' with 'grain' / granulated BP. Granulating BP is making it into pulverone ('rough powder') or pressing it and the breaking up the pressed cake into grains of powder ('corning'). A rocket 'grain' is a different thing. Sure, it can be made or BP too but it refers to the whole of the propellant charge burning as one mass. Basically the same as a fountain where it is one solid piece of composition packed together by pressure.
75 : 15: 10... Enough said!

#4 pritch

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Posted 01 May 2004 - 06:30 PM

Im not confusing that. What i mean is what mesh would you generally use for corning your crushed up black powder cakes to be used as rocket propellant.

#5 Richard H

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Posted 01 May 2004 - 08:26 PM

10-30 mesh would be fine for this purpose.

#6 pritch

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Posted 01 May 2004 - 08:48 PM

Excellent! thanks guys

#7 Matt

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Posted 02 May 2004 - 01:57 AM

Its AC/AD all over again hahaha

-MatT 2 T's DAMMIT!!!!
Try to run! try to hide! Break on through to the other side!! YYYEEEAAAAOOHHHHHHHHAAAAHHHHHHHH

#8 Kembang Api

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Posted 02 May 2004 - 03:45 PM

I had been making my rocket using BP mix ( 58% Pot. 32% Pine charcoal, 10% sulfur) and seiving through 100 mesh and dampen it with 70% alcohol (by spraying). Filling the BP using rammer and spindel. I had been succesfully launch it to a high of 200 meter without any payload.
My rocket is ID 20 mm, nozzel 7 mm, total length is 100 mm and core is 80 mm

Is there any different using Granulated BP in term of lauching height, speed and carring load?

#9 pritch

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Posted 02 May 2004 - 05:27 PM

I like the sound of your rocket very much. Although I will probally scale down a touch. When you say dampen it by 70% do you mean a mix of 70 parts alcohol and 30 parts water?

200 meters is very high for a black powder rocket.

#10 pritch

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Posted 02 May 2004 - 05:46 PM

I've just looked at 100 mesh and thats pretty fine. I cant even see the squares.

#11 Kembang Api

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Posted 02 May 2004 - 06:04 PM

Yes I dampen it with 70% of alcohol mix with 30% water. Just to reduce the dust during ramming.

The sound of the rocket is scary, I mean loud....

I used 100 mesh to seive my BP by using a vibrator.

For the high is not an accurate measurement. I tested the rocket near a 30 story building and watch the rocket from 400 meter distance. It goes more than twice of the building hight. That's how I came out with 200 meter.

#12 pritch

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Posted 02 May 2004 - 06:10 PM

Right I havent got a vibrator unfortunatly (trying so hard not to crack a joke). I think I will try making your rocket though. I need to get some alchohol from somewhere.




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