Aerotech RMS Propellant

[Draco_Aster]

IIRC Aerotech RMS motors use an AP based rocket propellant. I am interested in recreating the propellant grains to give atleast half the performance of the commercial grain. Has anybody tried this? Used a more avaliable oxidiser?

 

It must have a relatively low burn temp like the commercial fuel as not to destroy the motor.

[Blackhawk]

http://www.jamesyawn.com/

 

Go down to the part called "Reloads for Aerotech/Dr.Rocket Motors". He is talking about the 38mm motors specifically however it will give you a pretty good idea about what is possible (he is using Rcandy which is pretty easy to make).

 

Also grab SRM.xls from here: http://members.aol.com/nakkarocketry/softw.html

 

It's a design program for sugar rockets, and it should allow you to design reloads for smaller cases without blowing them up. IIRC Aerotech sells the motor liners, casting tubes, nozzles, O-rings etc for their motors through a parent company so you should have no problem finding parts for making your own reloads.

[BigBang]

I have worked with composite motors many times myself, and although the oxidizer can be changed, it is the binder that is harder to replace. The HTPB in aerotech motor can in some cases be replaced by epoxy, but a fuel will be needed, and will give much lower preformance.

 

If you can get the binder, and have acess to fine Mg, I would make AN motors since NH4NO3 is readily availble, and is quite cheap. This is about as close as you'll get to the propellant.

 

The O-rings can be found in many places. IIRC they are used in scuba gear. Just make sure they are silicone.

 

If you're making a reload, you MUST have a liner. This can be made of cheap high temp rubber. It would be better to use phenolic tubing however. These motors do burn very hot, nearly 5000* F in some cases.

 

If you want a "super-charged" propellant, you could always use a triple base, HE propellant. I'm not too farmiliar with these so maybe ask an HE person. Or if you can somehow obtain hydrazinium nitroformate, you can have some real fun

[TheSidewinder]

You could try some APCP (Ammonium Perchlorate Composite Propellent) motors. It's something I'm going to play with this Summer.

I bought the Firefox kit last year and didn't have the time to tackle it like I wanted to. I made a couple batches of raw propellant but didn't cast them, instead pouring them in paper tubes, cups, etc. The key is in the mixing, I've discovered. I also added too much plasticizer. I'm looking forward to experimenting this Summer, though.

 

M

 

EDIT: I need more coffee.... *yawn*

[artificier]

I know a nice ammonium nitrate propellant

90% ammonium nitrate

10% urethane plastic (plastic bowling ball)

 

all ingredient finely powdered with ball mill separatly but I dont know to add NC lacquer to make a cast propellant.

[Mumbles]

Plastic bowling balls arn't made from urethane. Urethane is a higher quality bowling ball, and it is not plastic-like at all. It is more like a stone or mineral.

[artificier]

yes but urethane i used in rocket propellant,just buy a old and used bowling ball for 10$ and you get urethane for the rocket propellant.

[Mumbles]

Old bowling balls probably won't be urethane. Chances are they are plastic or a hard rubber. Urethane is totally different from these. I don't think you understood what I said. If you used a plastic bowling ball, you did not use urethane in your mix.

 

By the way, the mix you posted has absolutly nothing to do with the topic at hand. Those propellants are Ammonium Perchlorate based, not AN.

[teknix]

Found this in a search just for FYI:

 

# In the 1960s, hard rubber balls were king.

 

# Polyester balls stole the scene in the '70s. (Most of the "house balls" in your local bowling alley are of the polyester variety.)

 

# The '80s saw the dawn of the urethane ball.

 

# Urethane balls matured in the early '90s with the introduction of reactive urethane.