59 replies to this topic

[dr thrust]

This formula works pretty good, using a clay nozzle and end-burner BP tooling:

Potassium Perchlorate - 75
DAP - Weldwood Resorcinol Resin - 19.5
DAP - Weldwood Paraformaldehyde Catylst -4.5
Dark Aluminum powder - 1

Add enough denatured alcohol to form a putty, and press into a casing. You can use a core for more power if your aluminum doesn't make the mix hot enough.

[pyrotrev]

I tried a similar formula and it definitely needed a core.

[Sambo]

What about using a NC lacquer to bind the propellent? anyone tries this? It might have to be quite concentrated 10-20% to get a good grain.
I believe Cooperman used dry NC powder to bind his ematches - this might be another way around it.

[dr thrust]

the beauty of the resin is the "ready" time, make and fire the same day

[cooperman435]

I dont technically use dry powder to bind my ematches. I weigh out dry nc powder to get my ratios correct and accurate the add acetone as a solvent to the NC and chlorate, I let it all disolve then add the Antimony trisulphide so the chlorate and Ant Tri have as much to seperate them from reacting when together.

Personally the resorcinol resin would be my suggestion as I would see it being a good burn rate modifier and excelent binder for a fast turnaround.

[dr thrust]

well heres my first whistle rocket and a 1lb nozzless with ti tail nozzless rockets

[digger]

well heres my first whistle rocket and a 1lb nozzless with ti tail nozzless rockets

Excellent, do you like the Ti effect in the tail (I think it is great)?

[dr thrust]

thanks, again it was another first for me using ti sponge, and i only used 1g in the rocket which i added to 20g delay above the core as ive read this stuff really tares up your tooling , and yes i was well chuffed with the results, but theres always room for improvement .

also no catos! this has to be a first for me, lol and the manufacture is simplicity its self with no nozzle or top clay bulkheads ,i just need to fine tune the tooling trying out different core diameters/lengths to see whats the best performance wise.

[digger]

thanks, again it was another first for me using ti sponge, and i only used 1g in the rocket which i added to 20g delay above the core as ive read this stuff really tares up your tooling , and yes i was well chuffed with the results, but theres always room for improvement .

also no catos! this has to be a first for me, lol and the manufacture is simplicity its self with no nozzle or top clay bulkheads ,i just need to fine tune the tooling trying out different core diameters/lengths to see whats the best performance wise.

As you know I have been using it for a while now. I have not had any obvious wear on my tools which are made from alubronze.

What mesh of Ti sponge were you using in the rocket?

[dr thrust]

hello! the mesh looks quite coarse ?, around 250-450 microns, i did try rubbing a bit on some scrap Ali which is what my "cobbled together cheapo homemade tooling" is made from and it scored it badly, ive got no lathe now, so im stuck until i can get another for improved tooling which is really holding me back at the moment.

Edited by chris m, 16 July 2008 - 07:18 PM.

[pyrotrev]

I don't think you need to worry too much about wear from Ti sponge, as in my experience it's relatively soft stuff due to its porous structure. Ti flake is something else altogether and chews anything other than hardened tooling up.

[dr thrust]

hm dont really know now! if its flake titanium, i got it off tin- ernet and have nothing to gauge it against, ill get some sponge from cooperman to see the difference, anyway found a nice vid of a 6lb nozzle less rocket lifting a 5" shell its not just me thats mad!, hoo dont they make a lovely noise setting off

Edited by chris m, 24 July 2008 - 10:22 PM.

[dr thrust]

hi, me again i ran a few tests last night with different fuels just for kicks, the first 70, perc 30 willow this gave an interesting whistle effect and i have no idea why it would? secondly i tried out perc bp 75,15,10 each chem milled separately then riced and burn rate tests looked very promising indeed but i found the propellant grain very hard to press it just would not compress and not very good performance from the motor.

lastly the same propellant+ ti pressed harder and she flew more like a nozzled rocket, so is it better pressing or including a metal to the fuel for a hotter more efficient burn? anybody care to elaborate, heres the vid test fuels

Edited by chris m, 04 August 2008 - 05:56 PM.

[digger]

hi, me again i ran a few tests last night with different fuels just for kicks, the first 70, perc 30 willow this gave an interesting whistle effect and i have no idea why it would? secondly i tried out perc bp 75,15,10 each chem milled separately then riced and burn rate tests looked very promising indeed but i found the propellant grain very hard to press it just would not compress and not very good performance from the motor.

lastly the same propellant+ ti pressed harder and she flew more like a nozzled rocket, so is it better pressing or including a metal to the fuel for a hotter more efficient burn? anybody care to elaborate, heres the vid test fuels

Cool. It would appear that you have discovered a new whistle fuel with that first one! I really liked the last one with the chuffer effect.

I made some fuel in the past using Barium Nitrate that had a similar effect when a metal powder was added.

[dr thrust]

thanks thats interesting! so it helps adding a metal powder , and whats the odds i cant make another chuffer again! most of the 1lb motors perform better than the 3lb,Er's i guess its the extra id of the bigger motors needing a lot more thrust, at the moment I'm just using normal bp rocket tooling( 1/3rd id core) so I'm going to try whistle tooling 1/2 id core on the bigger motors to see if the extra surface area of the wider core gives more thrust? I'm after a stubby hot motor about 1"x6" to lift a big payload how did the barium fuel work out nice and bright?

Edited by chris m, 04 August 2008 - 07:26 PM.