Polyester resin

[THEONE]

Has anybody before use any polyester resin as a rocket fuel-blinder

I am thinking to try an ANCP with polyester resin

 

Also i can not find the polyester at the chemical list of the Guipep, so i can not check the performance of this fuel

( Does anybody know if and how can add it into the Guipep's program list ? )

 

I am thinking something like:

 

75% AN

18% Polyester

6% Charcoal

1% Cuo (catalyst)

(maybe also + 5% -7% mgal)

Edited June 1, 2012 by THEONE

[gregkdc1]

I played around with the idea once but dropped it when I discovered that propellant made with polyester resin doesn't like to bond well to inhibitors, not to mention it is nasty smelling. The propellant you mentioned will probably burn but extremely slowly and may not generate enough mass flow to be any good for a motor. On the flip side if you made an uninhibited grain it might just have enough surface area to work? Idk I have never tried. Heat is the best catalyst for AN based propellants, lots and lots of it, either from aluminum or magnesium. The magnesium being the better choice for AN because it doesn't produce as much slag as aluminum. Also AN propellants burn at such a low temperature it’s hard to get aluminum to burn unless it contains almost 20% aluminum. This is what is required to get the flame temp hot enough to reliably melt through the protective oxide on the aluminum. Let us know how things go.

 

 

[THEONE]

Maybe dark German AL powder will work better

[gregkdc1]

Yes it should burn better. When I was experimenting with AN fuels I noticed that propellant made with bright flake aluminum seemed to ignite easier than spherical aluminum. On the other hand the higher surface area of the flake aluminum made the propellant to dry; it had soaked up all of the binder. This is compounded by the fact that AN has such a low oxygen balance you have to use less binder than you normally would with AP, KN or KP. I am not saying you can't do it but there are trade offs and reasons why people tend to stay away from AN. Here is a good AN formula form the Bulgarian rocketry guys.

 

60% AN

20% Clear silicone (any type works some people say you have to use the GE type one but the acetic acid ones don't react with the AN or the aluminum, this may be different if you use magnesium)

20% spherical aluminum

The propellant burns consistently and considerably fast for and AN propellant. It is flexible and has a decent density considering that you just mix it up. The down sides to it are that it is very hard to ignite (sometimes thermite isn't enough), hygroscopic and it makes huge amounts of slag that can plug the nozzle. While we are talking about nozzles the guys using this formula run it at a kn value of 200-300 and you will need to use graphite. Here is a link to this formula in action, this rocket isn't mine.

 

 

 

I really like the idea of AN propellants because they are so cheap I just switched to making AP composites because they are no longer regulated as explosives in the US. I would really like to see an ammonpulver rocket. The fact that you could potentially get a high ISP with a simple cardboard tube and clay nozzle would be quite an accomplishment.