Experimental rocket fuel

[NeighborJ]

I've been thinking of experimenting on a couple types of rocket fuel. I can't find any similar comps and I was curious if this is due to chemical interactions.

The first fuel is an Ap based sodium sali fuel. And the second is a normal sali whistle fuel with some of the sali replaced with hexamine. This is an attempt to slow the burn rate a little while maintaining a high gas production and possibly creating a larger flame presence.

It is not important for these experiments that they whistle. I just want to know if they will interact in any negative way as chemistry is not my strong suit.

[Jsugarlog]

I have never tryed AP with any kind of sodium based fuel yet, but from what in reading it looks like you are trying to slow down the burn rate yet keep keep the same amount of thrust if possible?? Sodium is usually used in fast burning compounds. I've found that adding an extra carbon fuel of some type charcoal or petrolium jelly. a small amount tends to slow down the burn rate yet keep the heat. I would be happy to correct myself if that isn't quite the question you are asking!

[NeighborJ]

I've made whistle motors with added charcoal and they worked well but it really seemed to buffer the cuoxy catalyst.

I've never heard of ap whistle but if it works and is indeed as hot and fast as I suspect it was my intention to add a small amount of hexamine to slow it down to a whistle comparable fuel but with a longer burn.

I'm kind of obsessed with harnessing whistle for a longer burn.

[Maserface]

There are a few whistle formulas out there that contain some AP, but I am not at liberty to share them. *tease*

 

I do however have a formula, untested, that a friend helped me come up with. The idea was to get a buncha thrust and a nice *woosh* sound. If you try it please let me know how it goes

 

Cosmic AP Pusher #1

75 AP

14 Na benz

8 dark Al

3 wax

Edited September 6, 2016 by Maserface

[DavidF]

I have the same interest, but a different way of approaching it. I plan to slow my burn rate by simply removing the catalyst in 76-23-1-3 sali whistle. If the burn is too irregular and choppy, I will add a small amount of perlite- as the Chinese do. It worked with my KHP whistle. All Chinese whistle I have seen is white. As I understand it, they use varying proportions of perlite to modify the burn rate to their liking.

[Jsugarlog]

Ya I've never messed with whistling AP propellants. I would would just stay open to suggestions, if I ever find anything in my experimentation I'll let you know!

[NeighborJ]

DavidF I can see how perlite would work but I was trying to keep the total impulse as high as possible and moderate the burn speed with slower fuel. I just don't like how the whistle fuel burns out at 30-40' and coasts the rest of the way to apogee.

Masterface, glad to see there are still trustworthy people in the world. I will give your formula a try but I'll need to order some more benzo for it. I will likely use mineral oil also due to my bad luck with wax. Don't know what the deal is with that.

Edited September 6, 2016 by NeighborJ

[DavidF]

Hmm, I think you and I look at it a bit differently NeighborJ. I'm not saying I'm right, but I'll just expand on what I said. It's my understanding that the 'catalyst' might be more accurately called a burn rate modifier. To me, that means that the thrust goes up because the whistle is being made to burn faster. But it doesn't seem to me that it means the total impulse goes up much. The reaction was going to happen anyway, it just happened faster with the catalyst. At lot of impulse in a whistle rocket is lost as drag too. Less impulse with less drag might be good

[NeighborJ]

Haha I can see where this is going David. To me it looks like what you are doing is taking a big bad ass sports car and sticking a block of wood under the gas petal. The perlite is acting as a filler, as in, it replaces energy packed fuel with an inert substance. This means that the fuel is less energy dense and cannot do as much work as if it was all fuel. How I use that energy is another subject all together. The most efficient car is a race car it is running at peak horse power and torque during maximum load. A Prius is not able to reach anything near it's maximum load due to emission controls. If I want a lower impulse motor I will simply use a smaller one. The whole reason of this want for a longer burning motor is not to spread out the energy over a greater distance but to try to optimize a fuel to burn at peak thrust for a greater distance. These are similar but not.

[DavidF]

OK, can we back up to before I would add perlite (if I indeed found it necessary). Is leaving out the catalyst also like putting a block under the pedal, in your opinion? Or would the same impulse be spread out over time?

 

If you want to keep the impulse up, may I ask what the impulse should be for whatever set of tooling you've measured it with? And when the burn time is too fast, what do you consider too fast?

 

I couldn't imagine embarking on a mission like this without first trying the simplest and most obvious thing, like dropping the catalyst.

 

To continue with the car example, it sounds like you want to put your foot on the gas and the brake at the same time instead of putting a block under the gas pedal

[ddewees]

[NeighborJ]

You are correct, the catalyzed fuel will have slightly less impulse than straight fuel. I was referring to your use of perlite. I'm about to experiment to see if ap based whistle has more useable energy than perc whistle, and if it does it is my plan to use that energy to extend the burn time beyond what perc whistle is capable of and with equal initial thrust. My plan of doing this is to use another(slower) fuel to moderate the burn and gain some useable thrust from this moderator as well.

[NeighborJ]

Dweebs I always love watching your test videos, always impressive.

DavidF in order to find that red line on a motor I need to start with the hottest fuel possible and turn the spindle shorter and shorter until it stops catoing. Otherwise I'd need to make a dozen spindles for every kind of fuel and only be able to use one or two of them. This is why I test with catalysts. When I find that upper sweet spot I am fairly confident that a slower uncatalyzed fuel will bring the motor back down into a more useable and reliable range. I've already done all the testing I am willing to do on standard whistle and am confident that what I'm looking for is a matching peak thrust but with a hopefully doubled burn time. This may not be possible but it will not stop me from trying.

I just don't want to regress by repeating experiments I've already done. I got a little heated and could not convey this info to you properly in that state of mind. My phone was acting up also and was making communication difficult by repeatedly bumping me out of this app in the middle of typing, very aggravating,and so I kept my messages as short as possible.

Masterface, I've just tried a sali version of your formula but in the four test motors I've made only one worked and not that well. This stuff is tougher to light than dog sh#t. I needed to dump a tiny amount of normal whistle down the core and press it in place by reinserting the spindle. This still did not ensure ignition so the last motor had a tiny increment of sali whistle at the top of the spindle in order to ensure flame on. This fuel spits and sputters horribly but it is not the formula you gave me. I don't see much benefit in adding these metals in the fuel other than as a visual effect. They don't seem to create enough gases. The one redeeming feature of this fuel is when it Catos it splits the case and all reactions cease. So it is a small pop and unburned fuel just falls to the ground.

I will still try the original formula when my benzo arrives.

[Maserface]

Masterface, I've just tried a sali version of your formula but in the four test motors I've made only one worked and not that well. This stuff is tougher to light than dog sh#t. I needed to dump a tiny amount of normal whistle down the core and press it in place by reinserting the spindle. This still did not ensure ignition so the last motor had a tiny increment of sali whistle at the top of the spindle in order to ensure flame on. This fuel spits and sputters horribly but it is not the formula you gave me. I don't see much benefit in adding these metals in the fuel other than as a visual effect. They don't seem to create enough gases. The one redeeming feature of this fuel is when it Catos it splits the case and all reactions cease. So it is a small pop and unburned fuel just falls to the ground.

I will still try the original formula when my benzo arrives.

 

I am very surprised at the difficult ignition, although that is very common with APCP. Its very possible that the typical whistle fuels just arent suitable for an ammonium perchlorate propellant.

 

Spitting and sputtering is also very common with AP propellants, Ddewees can tell you all about that .

 

FWIW I ran that formula through some propellant software, and it calculated a ISP of 240. The software calculates standard APCP to be 256.

[NeighborJ]

Masterface, I believe this motor may work a lot better either with a larger motor or under higher pressures than cardboard can handle. My tests started with 2oz and utterly failed, so I moved up to 4oz and that is when it started to work. I believe that a 3# tube will be the ticket. I only made a 100g batch for testing. I believe the AP I am using is 70micron but I am leery of milling it because I understand that can be dangerous. If it was finer it may work better. Also I think the dark AL may not be the best choice. In my experience carbon will tend to negate the effects of a catalyst by blocking the transfer of electrons, bright AL will likely work better. I even tried adding a little cuoxy to it with no effect.

I've ordered 5# of sali, 2# of benzo and 20# of perc to devote to testing.

This clip is a 1# test which machine gunned and was a lot louder in person, was kind of frightening but lost most of its thrust due to chuffing.

Edited September 7, 2016 by NeighborJ

[Maserface]

That was the formula above?

[NeighborJ]

It was a sali version and had mineral oil, for ignition purposes I pressed a 1/8" of whistle at the tip of the spindle. I've been trying different whistle to ap whistle ratios all day and I can't seem to build any case pressure. It burns quite well but has no gas emissions. I even went as far as to try a 1:5 nozzled end burner and could not get a better flight then what you saw. But the one Cato I had was pressed around a week bp spindle. It wants to operate at a higher pressure than what a tube can handle, I'm using nept tubes. It may have a better response to the benzo fuel but am still waiting on the order to arrive.

[NeighborJ]

Masterface, do you think cuchromite would help the fuel burn more steady or create more problems. The next question is, will a whistle/apwhistle fuel need two different catalysts or will copper chromate work for both?

I don't want to order any if the experiment has already been done by someone else who is willing to share. The next step is also to find some hi performance tubes to handle the pressure. I tried reinforcing these NEPT tubes with fiberglass and it became very brittle.

Edited September 9, 2016 by NeighborJ

[Maserface]

Copper Chromite is a great catalyst for APCP, but its damn expensive- I dont think it would solve any problems that red iron oxide might solve. I wouldnt think youd need two different catalysts if you are essentially blending the two propellants together. You are in uncharted territory (at least where I havent been).

[NeighborJ]

Hmm? Uncharted territory, first star to the left and strait on till morning. I'm wearing a hole in the floor waiting for my chems. They should be here today at some point. I've been turning varying length spindles for testing, all are 1# and increase in length by 1/2" each. This way it should make testing any comp a breeze. I used the pusher design and just stretched it out.

[NeighborJ]

My chems finally came, so I whipped up a few batches of regular sali whistle one catalyzed and one not. I kept on trying longer spindles until I got to the largest one. It never catoed with the uncatalyzed stuff but it does chuff between thrust and delay. This thing is insane fast and is traveling beyond a mile but could perform better without the chuffing. Is there anything I can do to eliminate this without adding a cat? I was thinking mabe an increment of cat at the tip?

Tomorrow I will turn yet another spindle at 6" then 7" until It self destructs. At that point I will start subbing in hexamine to replace some of the sali. I believe this method will produce an even better performing motor, and if it doesn't then I'll try steric acid or shellac.

I don't have all my chems yet so I won't be able to try the AP benzo fuel yet but I still plan on testing an organic AP sali version this weekend. I'll keep you posted

[Seymour]

Personally if burn speed is not desired, the only reason I'd add whistle fuels is if I wanted to use a Sodium salt to colour the flame bright sodium yellow.

 

Ammonium perchlorate burns very well with many fuels that contain lighter elements than sodium or potassium, and thus have less "dead weight" not contributing to gas output. Resinox is my favourite. Others will surely be more powerful, but Resinox is nice to work with (other than static from milling), and contains only elements that will form gasses. For a purely propulsion perspective an AP fuel will contain only Hydrogen, Carbon, Oxygen, Nitrogen and Chlorine (from the AP). Aluminium will not create gas but up to a certain extent ( the % depending on motor size and other characteristics) increase overall thrust due to how much hotter the existing gasses become.

 

However elemental makeup is not everything when it comes to energy output as more energy is released if a chemical has a lot of stored energy due to a strained molecular shape. Does this count enough to make whistle fuels more effective propellants than most conventional organic fuels in pyrotechnics, such as Red Gum, and Phenolic resins (which I believe also have a high tension molecular shape in places) ?

 

From an EFFECT perspective, maximum impulse becomes of third importance of course, after safety and how it looks/sounds and so on.

Edited September 10, 2016 by Seymour

[NeighborJ]

Wow the hexamine preliminary results are unexpected. The first test I've done has shown to me that hexamine dramatically accelerated the burn of the sali whistle fuel. This is contrary to my hypothesis which was that it should slow it down. I can only assume that it raised chamber pressure enough, due to the excess gas products, to increase burn rate. This formula was 76-23-5hex, no catalyst was used, yet it behaved as thou it was. I believe I can write hexamine off as a noteworthy failure for this purpose. The other organic fuels will also have this increased gas production and will make them unsuitable for this experiment.

I believe the next coarse of action is the conventional one. In order to slow the burn rate without sacrificing thrust, I will use a negative catalyst (tidioxide) and extend the spindle even more. This option was undesirable due to the need for excessively long motors approaching 10" for a 1# motor.

Seymour i can't really comment yet about the AP fuel as I have done very little to experiment with it. But I can say that it is likely my only option to get the power I'm looking for and from a normal sized motor. The effects will come later once I know what I've got.

[NeighborJ]

I'm making headway🙂. I've figured out that all my attempts at an organic AP whistle motor have been well below any operational pressures needed to make this work. The fuel will not burn on its own, however when I press a long KCLO4 whistle delay from the top of the spindle it comes alive. The fuel burns while it is exposed to the fire of the delay but as soon as the delay is burned out, all reaction inside the core is automatically extinguished whether the fuel is spent or not. I have found that the fuel burns very slow and has the potential to burn for a very long time. It is a work in progress but I believe I can make this work with some additional tooling.

[calebkessinger]

Are ya needing more core area with the same choke? are you running a nozzled motor? I have a couple ideas someone else gave me. more core, same length motor and same size choke.

 

I need to make one anyway.. I better dig up a 1lb spindle and try.