BP rocket sparks

[Bobosan]

I realized this question is better placed in the Newbie forum;

 

Skylighters 2oz rocket instructions below

 

http://www.skylighte...nce-rockets.asp

 

I've followed the Skylighter procedure with a nozzled 2oz but wasn't impressed with spark trail at all.

 

What issues might occur by adding the 80 mesh charcoal after powder granulation?

[FlaMtnBkr]

I don't think adding your coarse charcoal after your BP has been wet, granulated, and dried will help. In fact I think it will have the opposite effect. For one, the charcoal will tend to settle out and you won't get an even distribution in the motor. Second, when you wet everything together some of the nitrate will get absorbed into the charcoal. This is said to help the charcoal sparks because you now have an oxidizer helping the sparks burn and glow. Without the oxidizer it has to rely on atmospheric oxygen and the charcoal won't burn as well and might not even fully burn.

 

I think I would try soaking your coarse charcoal in a saturated KNO3 solution and drying it out. Then use this charcoal when you granulate your formula. You can try adding more coarse if you aren't happy with the spark trail and assuming you have a hot base BP it probably won't slow down the burn too much assuming you don't go crazy with the extra. Also using a charcoal known for sparks will help instead of one used to make hot BP.

Edited April 20, 2013 by FlaMtnBkr

[Bobosan]

Thanks for your reply FMB.

 

The chems are Skylighter except for a 50/50 blend of Skylighter 80 mesh and 80 mesh pine charcoal. My deviation from the original formula is probably where problem is since the pine is probably too hot to produce sufficient sparks.

 

On another APC thread there was discussion about Kingsford regular (not match light) being the charcoal of choice for spark production? May have to give that a try.

[nater]

Many people regard Southern Yellow Pine as the best source for sparks.

 

Another trick for getting good tails is to use a different comp for the delay. There is a trade off between producing thrust and having excess fuel to burn as a tail. To get around this, use two different comps. In a core burning rocket, the fuel above the spindle shows up almost immediately at launch. Try a comp like Tiger Tail above the spindle and see what you think.

[Bobosan]

Thanks for that tip nater.

 

Yes, these are core burners I'm experimenting with using 80 mesh white pine charcoal.

[Arthur]

Pine is regarded as good for spars and tails. As ever with rockets there is a balance between thrust from complete combustion and sparkly tail from incomplete combustion to be made.

[leedrill]

have you thought of investing in a lot of titanium it is absolutely wonderful stuff the first time i put it in a motor i said straight away i want that in every delay grain from here on and if you get your orange sparks sorted out you can press a bit of chrysanthemum 6 or something for an increment or two before using a mix with added titanium and you get a lovely colour change on its way up

[Bobosan]

Think a combination of everyone's suggestions will be tried....one change at a time though. I have Ti and steel for sparks but wanting to get good charcoal sparks first, like those showing in the Skylighter article vids. Those rockets are slow to lift and mine are really quick but do not spark like that. Arthur mentioned this and perhaps I should slow these motors down a bit. The Skylighter article is just screened fuel whereas mine has been ballmilled.

[dagabu]

Other woods with lots of sparking potential are:

 

-Spruce

-Red Cedar

-Poplar

[Poindexter]

I bet it's the ball milled chemicals make the powder hotter/ faster than the screened.

 

Does anyone know the burnthrough rate on screened as described in the skylighter article?

 

I am running one to two months behind bobosan I think. I would hate to have to shut down my ball mill to make the turbo pyro kit work with screened fuel.

 

Maybe I'll have to make a screened batch, time it down the one meter saw horse top and then figure out how short a run time that is for same ingredients in my ball mill. I am guessing the screened version will have more uniform particle size than the ball-milled short cycle, even if the burnthrough rates are the same.

 

In the meantime I'll look for spruce, red cedar and poplar next time I am in Lowes-Depot.