Experimental rocket fuel

[OldMarine]

I'm the opposite. I'd rather discover things on my own, than follow a step by step tutorial.

 

Nice baby strobe Caleb, that was pretty cool.

 

Ha! That's why I love ya! You are the guy breaking the brush and getting in there. Some of your gerb vids are my go to pyro fixes.

Let's see... I recall dogs howling and such after an unexpected report on one big one...

[ddewees]

That was a fun one... Early on in testing.

 

Caleb and I both were running out to the workshop to test cored gerbs after Lloyd gave us just enough information to get us into trouble.

 

Five fire truck ended up coming for that one, but couldn't find anything when they finally arrived. Made it out by the skin of my teeth.

 

[Video]

[ddewees]

That was just the nozzle blowing out too! I couldn't believe the tube was still intact.

 

http://i1149.photobucket.com/albums/o588/SaltLakeAreaPyros/9-19-2015%202-33-16%20PM_zpst7nf6igb.png

[Mumbles]

You might be interpretting things that just aren't there or aren't reality. There isn't some sort of rocket illuminati. I can't think of a single rocket builder that is stingy with knowledge or won't share techniques. They're some of the most generous people I know. This goes for basically anyone who I would consider decent to good at rockets, not just the masters.

[DavidF]

NeighborJ must be talking about HPR people. I heard that they look at us pyrotechnic rocket folks with disdain. As far as pyro rockets go, I have to agree with Mumbles. I can't think of any pyro rocket guy that's ever been stingy with knowledge. I can think of a lot of us light-on-experience-but-heavy-on-ideas guys that are hard to keep quiet

[NeighborJ]

HPR guys tend to follow exact formulas of known and proven fuels. It is the motor designs which are the variables. The goals are notably different in HPR. If you are able to follow proven techniques there is no issue there but the moment a different effect is added and problems are had, the eyes start rolling.

Yes DavidF I admittedly have a lot of out of the box ideas and little experience to make use of them but the box in pyro is not exactly defined and if it is, then those parameters should be made public knowledge.

Ultimately my frustration is centered around the lack of AP formulas which don't use fuels which are made of unobtainium. If I had a working formula then all these crazy ideas and experiments could then be relegated to the realm of tweaking.

In other words, I simply need a better starting point and can't make headway without a practical formula and technique.

[NeighborJ]

Hehe.

[ddewees]

I've had the best luck with these:

 

Lavender

70% AP

15% Resinox

9% SrN

3% MgAl -100

3% CuCO3

 

Green well tested

50% AP

30% BN

14% Resinox

5% MgAl

1% Fe2O3

 

Cerise Rocket (Pink) well tested

54% AP

25% SrN

16% Resinox

4% MgAl -100 / Dichromate treated

1% CuO

 

 

They're all posted here already though, just got to do some searching or reading. Start by reading all of Seymour's posts if you want fun, interesting reading. That's what I did.

[NeighborJ]

OK, thanks Ddewees, I am well aware of those formulas and indeed I have seen them posted several times. It had always been an impossible formula for me because they all contain phenolic resin which was of coarse unobtainium, or at least cannotfindium. With the recent topics about resin I have found where to order it. I hope this explains why I was searching for anything which did not contain phenolic asphaltum or HTPB.

I hope this will get me pointed on the rite track, my last test ,today was a 1#, 100g Cato or mabe it would be better classified as a detonation. It felt as if I got punched in the face, even from 100' away. It was an unscheduled and hastily executed evacuation from the test site, to avoid any complications from law enforcement. And now I'm at home with a headache and pondering the fact that I will need to find another test site so no-one gets wise. This is why I avoid loud whistles and salutes, Catos are loud but not nearly as loud as a det.

Thanks again, and I'm sorry if I got a little cranky this morning, I know there is no "conspiracy" to hoard info and some things should not become public knowledge (like the formula in todays experiment).

[calebkessinger]

lol.

Thanks Dan!

I've been working on my strobes for a couple months now. I think between a Dave F. and a couple of us other guys fooling around we are going to knock the secrets out of making good strobe. It's all in the Magnalium I believe. and getting past a poor mix by adding milled magnalium to it.. bam headed in the right direction. I've now heard Steve LaDuke's, Joel Harmon's, and mine and can say I can't tell the difference between any of the good ones. Each rocket is different but for the most part the fuel is the key.

 

Neighbor J.

Some of us are completely ignorant of the AP fuels. Lots of folks don't even want AP in their shop I believe. So the void of info you are finding might just be that only a handful of people on these forums have fooled with them. There are thousands of good pyros that don't ever get online also. Keep your head up, There is always more to learn.

[Mumbles]

If you can't find phenolic resin, asphaultum or HTPB it's a personal problem, not a systematic problem. All are regularly available without any issues. There really isn't any advice to give beside "do better".

[NeighborJ]

OK, I will do better to explain. It should have been written as: I couldn't seem find the right kind of phenolic resin, the kind I have had the most success with in the past was a epoxy used for bar countertops. It was hard to light and completely washed out any colors and could only be used for Bates grains. I have scores of samples of resins which do not suit my purpose, so I had decided to wait until I could locate the good stuff.

Asphalt can be bought handily but is again not the kind of motor I am looking for and should not have been included on that list.

HTPB, can be found also with, some effort, but again it is not suitable for pressing in a cardboard tube and is better suited for Bates.

The personal problem you refer to Mumbles was my failure to explain all this, in an already very long post. I should not have just lumped them all together and stuck a general label on them.

[ddewees]

Most people buy their resin from Jim Widmann.

 

https://ctpyro.com/content/phenolic-resin

Edited October 8, 2016 by ddewees

[stix]

Neighbor, are you looking for a 'whistle sound' as your original post suggests is important, or/and colour - or, a suitable binder for AP propellant?

[Seymour]

All those coloured fuels are quite over fuelled. According to a formula I found here on APC the ratio of elements in Resinox is C48 H42 O7.

 

The reality depends on the actual ratios used, purity of the feedstock chemicals, and if hexamine is used as a cross linker and so on.

 

But I have to go with something so I'm doing my maths based on Resinox being this. If someone has a more accurate emperical formula or could verify my one that'd be great.

 

Anyway, the coloured ones are over fuelled which is fine. A lil extra fuel expands the flame, and these are firework/effects rockets.

 

Anyway, I like to run some simple maths for organic fuels to determine the maximum ratios for production of all carbon in to Carbon monoxide (CO) (and H to H2O) and secondarily the other extreme being Carbon dioxide ( CO2) and H2O.

 

 

Rounding to the nearest 0.5% away from the limits my data is

 

AP : Resniox = 80/20 for CO, and 87.5/12.5 for CO2

 

I often wanted to use wax for these formulas to make them lovely to press. Wax is something like C31H64.

AP/Wax = 87.5/12.5 for CO and 91/9 for CO2.

 

I like to add 2-4% wax to things to make them press nicely. However wax needs so much AP to burn completely that I decided to look for an alternative way of getting a dust free powder that presses in to a nice slightly plastic grain.

 

Ultimately I intend to use Polyethylene glycol, but I am currently using Propylene glycol just because I have it and I have yet to buy PEG. Much like Adding Alcohol softens Resinox, so will Propylene glycol, or the more fluid chain lengths of Polyethylene glycol, except these glycols won't evaporate away having boiling boints well above that of water.

 

Adding 1% Propylene glycol to Resinox fuelled AP mixes has had the effect of making granules that behave much as if the composition contained 4% wax, with much less impact on the fuel balance.

 

For Ammonium perchlorate and Propylene Glycol (C3H8O2) it is 76/25 for Carbon monoxide and water, and 83/17 for Carbon dioxide and water.

 

The downside of Propylene glycol is that it can pick up water from the air, as can AP. However in my view having 1% Propylene glycol in a fuel containing AP, Resinox, Aluminium and your catalyst(s) of choice is not going to cause any issues, but I would take this in to account in more moisture sensitive compositions. While dichromate might be able to effectively allow the use of Mg and AP, I am still of the feeling that anything that can de done to exclude water should be done to get a decent shelf life. I mean drying chems before mixing and sealing the comp in nitrocellulose kinds of exclusion, so I would not use Propylene glycol in Mg or MgAl fuelled AP mixes and store them for ages and expect them to stay good.

 

For example I want to make some nice and reliable AP motors which I want to be quite powerful, have a decent flame, but be very reliable, easy to use, stable and work at low pressures (like in a cardboard tube). The Max % Al in AP motors seems to be a whopping 20% in some large space rockets, where the hydrogen seems to largely come out as hydrogen, not water. However I'm lead to believe that 20% only works easily in larger motors because otherwise Aluminium combustion is often complete.

 

Why not 15%, even if combustion is incomplete, the completion of the combustion of excess Al will make that great bright flame.

 

I want 1% Propylene glycol. Burning to create Carbon dioxide and water this needs 4.9% Ammonium perchlorate to burn it.

 

AP and Al burning to Aluminium oxide, water, HCl, and Nitrogen is 72.32/27.68

 

So the 15% Al needs 39.3 AP to burn it. We have 60.2 % already accounted by the Al, Propylene glycol and oxidiser needed for them to burn. there is already a lot of Aluminium so there will be a lot of heat. Fuel rich mixtures often burn well and because the lighter CO molecules will be more numerous than CO2, and hot from the Aluminium, there may not be much disadvantage in choosing monoxide for the resinox. One advantage would be an increased flame size. I like rockets to look impressive and will happily choose to compromise in impulse for effect.

 

This would be something like:

 

76% Ammonium perchlorate

15% Aluminium (atomised)

8% Resinox

1% Propylene glycol

Catalyst(s) to taste.

 

Another example, only 4% Aluminium and this time largely geared to Carbon dioxide.

 

84% Ammonium perchlorate

11% Resinox

4% Atomised Al

1% propylene glycol

 

 

Of course the actual combustion will never match my equations, but when dealing with basic assumptions of carbon and hydrogen, oxygen and Aluminium forming CO/CO2, H2O, Al2O3, I think that these numbers make it a bit easier to come up with formulas that have characteristics you are after.

 

I screen the powders together, add the 1% Propylene glycol to +4% or so acetone, add the powders, mix thoroughly and granulate as the acetone evaporates.

Edited October 9, 2016 by Seymour

[NeighborJ]

Wow guys, thanks for the replies.

Ddewees, your link for Jim is exactly where I've ordered the resin from, and when it gets here I believe it will unlock and open up many more possibilities.

Stix, the original goal for these experiments was a longer burn time and comparable thrust to whistle based fuels. The suitable binder, fuel additives and motor dimensions were the variables. I suppose the performance was key and the possibility of color and other effects would have come second.

The whistle fuels don't seem to whistle at all with AP and in fact as soon as the gasses become stressed enough to whistle, the motors tend to chuff and self extinguish. But I've run into several strobeing effects and most notably a whistling strobe which I have been using a lot of.

Seymour, I find it interesting that you had used PG as a binder. I've used it before in a flash motor as a binder and it worked great but like you said it is hygroscopic and so I didn't experiment any further with it. I have most recently adopted the use of NC mixed with mineral oil which seemed to help seal the motor from moisture quite well with the added benefit of not over saturating the comp with fuel. It does not harden as you would expect because the oil prevents the nc from directly binding to itself. I had considered using the PG in the NC but I am not sure if it could create a certain undesirable explosive reaction. The preliminary tests had resulted in an extremely violent and concussive Cato.

It is going to take me a little while to digest all your info but it certainly will help out a lot.

[ddewees]

I found the formulas work best without any binder, but with enough pressure, consolidate nicely. It's somewhat messy, but you get a rhythm down after awhile and it's not unmanageable.

 

Wish I was still active, I'd be trying those latest formulas out today if given the opportunity.

[calebkessinger]

Did i see you guys had another successful test flight Dan?

[ddewees]

Yup, 5 landing with the same rocket, and the capsule deployment was a success.

 

That's not my project though, were working on the New Glenn.

 

http://spacenews.com/wp-content/uploads/2016/09/New-Glenn-.jpg

[OldMarine]

I need a drool towel if I even dream of working on something of that magnitude. You must wear a terry-cloth jumpsuit with bib to get paid to actually do it!

[NeighborJ]

Damn, that thing is huge. What size press do you use for that? If you are still taking applications for astronauts, I'd like to nominate both presidential canidates for the maiden voyage to Andromeda.

[calebkessinger]

WOW!

Those rockets are awesome!
The astronaut farmer was on tv yesterday.. Talk about my hero.. ok.. it's fiction. But i can dream right?

 

25 mil!

That seems extreme. carve an entire part out of solid stock I guess. That's gonna be cool. I'm an idiot for not going to college and becoming an engineer.

[NeighborJ]

Ddewees you are certainly living the dream, or at least my dream. I can remember idolizing Robert Goddard at the age of ten, I had every NASA book in publication and went to model rocketry camp every year until 16. I literally thought I could be an astronaut.

It turns out that I enjoy doing things with my hands more than with my brain. I guess it's just as well, I don't think NASA could have handled another hot shot loose cannon. I find now that I'm more interested in the friction welding process they are using to fuse those large machined aluminum bulkhead pieces on the capsules.

Edited October 10, 2016 by NeighborJ

[NeighborJ]

OK, so I know I haven't been able to do any testing on Seymors formulas for a while but with the time off of work it's time to revive my efforts. Ive spent some time experimenting with the Phenolic resin in stars to get more familiar with how it burns. I'd eventually like to work on a perc formula as well as a whistle but for now I'm starting with two of the three formulas provided by Seymour.

I've decided to start with a coarse 400 micron AP as well as coarse 120 atomized Al and I expect to have ignition problems but I can always try finer chems later. The motors will start as nozzleless for initial testing and I'm sure that I will need an improved nozzle mixture when they start eroding. I'm trying to make these motors from the ground up so I want to document all the failures and successes as well as only making one change at a time to get a better understanding of which changes are doing what.

Edited November 7, 2016 by NeighborJ

[Seymour]

If you're not using a nozzle, it might help to use both CuO and Fe2O3 as catalysts. At least this is what I've used when I want to make AP mixes faster burning and easier to light, though I only have experience using AP compositions without nozzles when making go-getters.

 

400 micron is relatively coarse, especially for nozzles, but it should still burn well, this is less than 40 mesh from the google search I did.

 

For really small rockets (1/2") the best mixes I made were using AP that had been remotely milled for 15 minutes or 1/2 an hour with the catalysts in a ball mill.

 

However I'm not sure to what extent milling AP is dangerous. I know it can explode when being milled and that it gets quite dangerous as it gets really fine. I have tried to avoid this by only milling it briefly, but then I've also added catalysts... I've also used a coffee grinder occasionally, but I consider this worse because it is not done remotely.