Deployment charges

I've decided to fill in the time between now (mud season) and summer (rainy season) with a small research project. I figured I'd ask folks to point out
any obvious flaws in concept or methodology before I spend a lot of time on it.
Scanning the net for information about deployment charges, I find lots of anecdotal reports of the effectiveness of various powders and charge prep methods, but no specific comparative data. Given that I live in a place where setting off a couple hundred small charges will never be noticed, I thought I'd try to develop such data. If it's already out there, PLEASE point it out before I get started :)
GOAL:
Determination of viable alternatives to commercial Black Powder, and generation of a table of relative effectiveness for different powder types and canister configurations.
APPARATUS:
A piece of electric fence wire (continuous steel wire, approx 1/16" in diameter) will be stretched horizontally between two anchor points, and tensioned to a specific loading before each test series. The actual tension is somewhat arbitrary... at least 150lbs, max something less than the breaking tension of the wire. The idea is to create a replicable condition, with no primary resonance.
Below this wire, at one end, is secured a BP "cannon", simulating a 4" rocket body tube. A 16" long, ~16 ounce "slug" representing a nose cone will be suspended from the wire by 1/4-20 eyebolts at two points, in a manner which allows the slug to hang level on the wire, and to be inserted in the cannon without putting tension on the wire/eyebolt connection. After firing, the slug will be suspended from the eye bolts no more than one inch below its starting position.
Before each test series, the wire will be tensioned and cleaned with a light petroleum solvent (WD-40). Temperature and barometric pressure will be recorded for later data adjustments. Further, a "reference charge" will be fired to insure that the apparatus delivers generally consistent results. This reference charge will be something like 1g of ffffG Swiss black powder, in a specific type of charge container, wadded a specific way.
All charges will be ignited by the same type of low-current ematch, specifically, built from Aerocon Hotheads coated with Shimizu H3, and fired from a 12v high capacity battery. All pieces of the apparatus will be created from standard materials so that they might be easily replaced in the event of failure or excessive wear.
METHODOLOGY:
Each prepared charge will be inserted in the 'cannon', the 'slug' inserted, and the charge fired. The distance the slug travels down the suspended wire will be recorded. After each firing the 'cannon' and 'slug' will be cleaned of any residual powder or debris. At least two firings of each configuration will be conducted.
Charges will be prepared per the research matrix. A standard weight of powder will be established and used for each test (probably on the order of 1g). A commercial powder scale will be used to insure accuracy. Several types of canisters and wadding methods will be tested, as well as several different types of powder. Lists below (feel free to suggest additions)
Powders:     ffffG Black powder (swiss, goex, red dot)     fffG Black Powder (goex, red dot)     Nakka's Crimson Powder     Pyrodex P     Homemade meal BP     Homemade granulated BP     Homemade sulfurless powder     Composites (i.e. pyrodex + x% meal BP)
Containers:     Plastic 2.0ml with snap cap (tall and narrow)     Cardboard tube (shorter and more broad)     Baggies     Open pan
Wadding:     This is the "meat" of the matter, and an area where I may be offering new     info, if preliminary tests pan out. Suffice it to say this will include an     array of materials and methods, from loose "flash in the pan" discharge to     tightly contained by a number of methods, depending on the charge     container.
Hmmm... I think that describes it in general terms. I'm no technician, just a backyard hack, so it wouldn't surprise me a bit to find that I've missed something important. Comments and criticisms would be most welcome.
Kevin OClassen NAR 13578 TRA 10569
kevinREMOVEMEatREMOVEMEback2bed.com
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Hi Kevin: Sounds like you'll have lots of fun!
Another possible enclosure is a "penny wrapper" that has been wrapped in three or four layers of masking tape.
Two issues you won't be able to, easily, deal with: microgravity and atmospheric pressure.
You might want to take a look at http://www.rouse-tech.com/pdfs/CD3%20MANUAL%20DIST.pdf for the discussion of pyrotechnic charge failures due to lower atmospheric pressure. I haven't, yet, flown a hobby rocket high enough to worry about this so the point is academic for me.
It seems to me that "untamped" charges may travel away from their ignition source during the coast phase of a flight. If you're using containers with "loose" charges it might be interesting to try the exact same charge but in different orientations.
I'd be very interested in seeing you also systematically evaluate nichrome wire as well as e-matches. There may be regulatory issues surrounding e-matches and I'd love to see some solid data that removes yet another possible inspection/storage hurdle.
That brings up the power source. Is the high capacity battery you are specifying flyable? Maybe you could use a something like a nine Volt tranister battery and capacitor instead? That would make your ignition system much more "flight like."     Best wishes,     Will
Kevin OClassen wrote:

--
Will Marchant, NAR 13356, Tripoli 10125 L3
snipped-for-privacy@amsat.org http://www.spaceflightsoftware.com/will /
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On a quick read, there is no test using piston ejection.
Given your test setup, no test for deployment at altitude. The ground level pressure will vary a little, granted. It would interesting to see the changes at 1000ft intervals say to 30,000ft. But that is beyond the scope of your setup.
Red Dot is a smokeless power.
I do not know anyone who produces their own black powder. I am certain that there are those that do. I would be concerned about consistency from batch to batch, individual to individual. I see that testing of homemade BP to be of limited value
There is no mention on adjusting the amount of tension the body tube would assert on the nosecone. Is it a tight fit or loose fit fit.
BW
Kevin OClassen wrote:

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Agreed, to all of that. However, I'm not testing the effectiveness of deployment systems, rather the relative effectiveness of the various powders when contained and wadded in the same manner, against a standardized resistance (the slug on the wire). I also agree about the consistency issue with homemade BP, but wanted to include it as I do make my own. Also, since I'm including Nakka's Crimson, I had already opened the field to these issues. Thanks for the reminder about N/C fit. I've been considering a method to assure that the release force is the same test to test, but haven't settled one yet. Again, my goal is to test the powders, so the more variables I can minimize, the better.
Kevin O

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Hopefully, you've read my ejection test reports posted at http://www.alaska.net/~aleckson / Granted this site hasn't been updated in quite some time, but there is some info on the main page, then take the link to the smokeless preliminary report.
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Thanks, Scott. Very interesting and useful information.
Kevin O
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Kevin, Here is a link to another method for containment that has been working for me.. http://hometown.aol.com/tfish38/page16.html Tony
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Kevin,
Have you considered trying to measure the volume of gas a given weight charge will generate. The function of an ejection charge is to create adaquate pressure within the rocket so that the two pieces seperate. I think it's good idea to try to determine the efficiency of varius things used for this. I've found that 3f bp seems to do the same as 4f but with a less energetic release of gasses. I understand that some people have been sucessful with Pyrodex. Anyway, it's worth thinking about.
Phil
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