Galcit Rocket Propellant and tooling

[willowchar]

I am interested in constructing a 1 lb. rocket motor using Galcit propellant.

Wondering if anyone can give advise as to what type of asphalt to use as the fuel?

Also mixing procedures and what size of spindle and loading pressures to use.?

Thanks.

 

[Arthur]

https://www.nakka-rocketry.net/propel.html gives some answers, but too few for completeness. It's highly likely that you will need advanced rocketry assistance with the method. Some rocket comps are poured hot and left to set on cooling, some comps are poured cool and left to set by chemical means (urethanes, polyesters etc.).

[willowchar]

Thanks for the reply Firebreather,

I realize the original process requires using heated/melted asphalt at 275 degrees F.

Wondering if one could use some sort of bituminous based oil as an alternative to negate the hazards of working with such high temperatures?

Thanks.

[Arthur]

If hot bitumen is "too hot" then what about the flame. If you want to melt bitumen it will be at it's melt/softening point. Remember that the grain shape is important, you need the grain to burn before heat gets transferred and the next bit melts and runs out of the nozzle.

 

If you need there are cold or cooler casting fuels. Fuels that cure on standing will not need so much heating but will need loading and de-gassing before the cure process completes.

 

If this is for a solid fuel rocket amateur rocketry style usually the softened but mixed fuel is poured in and de-gassed.as it hardens. If it's a firework rocket then it would normally be incrementally pressed. However if the science and engineering is right any method works, but do tests in a safe place first.

[NeighborJ]

I have made many galcit rockets without the prescribed hot incorporation method.

 

These motors can be built by screen mixing the perc and gilsonite then adding 3% mineral oil to a petroleum solvent such as naptha and granulating. The motors can then be pressed using standard nozzled black powder tooling. The nozzle is a must. The fuel is difficult to ignite and absolutely requires the mineral oil to achieve sustained ignition.

 

I solve the ignition issue by pressing a thin increment of whistle at the tip of the spindle and top lighting the core. This breaths enough fire down the core to achieve complete ignition.

[willowchar]

Thanks for the feedback NeighborJ

What diameter/length spindle are you using for a 1lb motor?

What type of fusing system do you use to ignite the top of the core before the comp below?

 

Thanks

[shockie]

This old thread may shed some light:

https://www.amateurpyro.com/forums/topic/6266-jato-rocket/?do=findComment&comment=80564

 

this definitely will help:

 

https://www.worldcat.org/title/preparation-and-some-properties-of-an-asphalt-base-solid-propellant-galcit-61-c-galcit-report-no-22-project-no-1-1944-may-1/oclc/733105607

 

and so will this:

 

https://www.rocketmotorparts.com/Asphalt_Based_Solid_Rocket_Propellants_by_Chuck_Piper/p1577809_17391641.aspx