Best igniter for ejection charge

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redsox15

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Hi all,

Over my christmas break from school I am hoping to get started on my first rocket using dual deployment. On the topic of ejection charges, what are your opinions on the best/most reliable igniter for an ejection charge?

Thanks for the help

Matt
 

mikec

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On the topic of ejection charges, what are your opinions on the best/most reliable igniter for an ejection charge?
There are plenty of good options. I personally like Quest Q2G2 igniters. They are very low-current so you don't have to worry about battery state of charge as much, they're readily available, and they have insulated leads. On the down side they are fairly short (not much of an issue if your charges are on the avbay bulkheads.)
 

Sandy H.

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I have purchased from Quickburst also, but am using up the last of my Mtek's first. I've heard that Q2G2's work with some altimeters and I may try them soon too. Research blackpower vs Pyrodex if you are considering using Pyrodex. When I run out of BP, I am going to ground test with Pyrodex and try to go that route, but it may have some pitfalls.

I crashed my first DD rocket due to too small of a charge to break the shear pins in the nosecone. Ground testing could have caught that, so I'll again recommend ground testing. I also switched from 2-56 screws to styrene rod, but I think that with the proper implementation, 2-56 screws work fine.

Enjoy the shorter walks!

Sandy.
 

n5wd

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... I am hoping to get started on my first rocket using dual deployment. On the topic of ejection charges, what are your opinions on the best/most reliable igniter for an ejection charge?
One of the things that may color your decision is whether you have, or can get an Explosive Users Permit from the BATFE. E-matches (the low-current igniters normally used in deployment charges) are regulated by the ATF. E-matches that you build yourself may or may not be available without sending your EUP information to a vendor.

On the other hand, the Quest igniters are being sold freely, without the explosives permit.

I'm just getting started in dual deployment, myself, and am going with the Quest igniters...
 

kandsrockets

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I have been using nothing more than a piece of cat 5 wire with 6 wraps of 40ga nichrome wire. This requires an altimeter that has hi output. I use Perfectflight Hialt45 Missleworks mini and Art2 altimeters and have over 80 flights using this setup and have never had a failure. One big key thing is do some ground testing. Pyrodex works but requires more containment than BP does to get it to work.

Sandy,
Watch styrene rods. I had problems with it not shearing but just bending over. I am glad I found this when doing some ground testing, since then I have used nothing but nylon screws
 

redsox15

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thanks for all the input all! One other question...do I need a permit to get the 4F black powder for these charges?

Matt
 

rocketsmith

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I use AG1 flash bulbs (Robbies rockets) for my charges I love them, 100% reliability so far, no LEUP and no pyrogen. I use 1/2" pvc caps to hold 1/2" copper tubes for the charges.

A word of caution on using Pyrodex. I tried for my level 2 last month using pyrodex and the drogue charge went off but did not burn completely resulting in a drogue failure. Pyrodex burns much more slowly so it will often evacuate the powder from the charge container before it burns completely. I tried again this month using a longer charge container (about 5" long) tamped tight and filled with cellulose wadding and taped over the end of the tube.
I got complete powder combustion all right; it blew up a piece of 4" loc tubing. I did have fins slotted into the tune by just the thickness of the tubing with no fiberglass reinforcement, so I may have had this problem due to a design flaw.

Pyrodex is cool because of the lesser regulation but it is much more tempramental than B.P. I ground tested 3 times and it was a-okay but in practice it failed. Take this info with a grain of salt as I know the design flaw contibuted to the catastrophe.
 

powderburner

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do I need a permit to get the 4F black powder for these charges?
You can have 50 pounds of black powder without any LEUP or other permit if you are going to use it in a powder-burning firearm, antique cannon, or load it into "period" cartridges (like the wild west cowboys used to shoot) if you are into cowboy action competition. But if you use the black powder for any other application (rocket ejection charges, flashpan ignition, spider ignition, separation devices for side boosters, etc) you have to get a LEUP, have a storage locker, act nice during midnight inspections, and all the rest.

Even if you are only using one grain of the stuff. (A "grain" unit of measure is 1/7000th of a pound, hardly even enough to see.) Go figure.

The practical side of things might suggest that chances are just about nil that you would get caught for using a gram or two of BP in your ejection charge, but I don't recommend it. If it was me, my luck would be that some bloodthirsty agent would happen to show up just as I was prepping my rocket....and I don't like Leavenworth. YMMV.
 

MarkH

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What if one were to use the motor ejection charge for altimeter ejection in place of motor ejection, single deploy? Or what about using the motor ejection charges (that AT sells seperately) for altimeter based DD? Gray area?
 

powderburner

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We have so many of them because the authors of all this legal stuff only concentrate on whatever single thing they are trying to regulate and don't consider "side effects" of their legislation

I think the way the law is written (and that's an important point, because I am not a lawyer), it says something to the effect that BP used in model rocket motors is exempt. Logically (a dangerous thing to try to apply to legal matters), an ejection charge, being "part" of the motor, is included under this exemption. I don't read any part of the law that limits this exemption only to BP that is manufactured as ejection charge material at the same time as the rest of the motor, so I presume (again, I am not a lawyer) that BP designed to be used for ejection charges in a model rocket, even when manufactured separately from the motor, are still exempt from legal control and regulation. I would expect this coverage to include BP as in the AeroTech supplies for the electronic fwd closure.

Speaking of gray areas, I think there is also some wiggle room regarding BP and government regulation in the case of make-your-own gunpowder. I have read through the laws over and over, and have talked this over with a lawyer, and I can't see any applicable controls....unless you try to remove it from your property, or transport it on public highways, etc, which puts you right back to scratch. Anyway, DIY BP usually does not perform as well as commercial stuff (at least, it takes a lot of work to get equivalent performance). But it sure would be nice if one of our govt agencies would copy the Canadians.

Next problem would be: would they write the new exemption to recognize the "real world" consideration that you will probably have to purchase, store, possibly transport, etc, a minimum of 1 pound of the stuff even if you only use 1 gram in your ejection charges.
 

cwbullet

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I wish TRA, NAR could get an exception to policy on black powder and matches for rocketry.
 

bobkrech

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I wish TRA, NAR could get an exception to policy on black powder and matches for rocketry.
While NAR and TMT represents 100,000+ youth (non-voters) who fly rockets each year, the ~5,000 NAR members and ~3,000 members which is ~6,000 folks if you account for duplicate memberships, represents ~4,000 votes, so we have no political clout by withholding 4,000 votes distributed over 50 states. Considering that US voting age population is slightly over 200,000,000 and the number of registered voters is 150,000,000 and just over 130,000,000 voted in the presidential election of 2008, our 4000 votes (0.003% of the votes cast in the 2008 Presidential election.) don't represent a hill of beans to the legislators.

On the flip side, NRA represent 8,000,000 members who vote and advocate their position to their legislators, and 60,000,000 shooters who vote. That's almost enough votes to outright win an election, and certainly enough votes to swing a close one. The legislators listen to them.

Bob
 
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hardinlw

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And having Moses (Charlton Heston) as spokesman for years didn't hurt NRA either.:)
 

Diosces

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I use Oxrals, JTek's, Mtek's etc. Depends on what vendor has available.
I use the PerfectFlite MAWD and ALWAYS ground test when I switch ematch or build a new rocket.
Ground test is the most important prep for successful recovery imho.
I use Pyrodex due to availability, even tho I have a LEUP.
As other mentioned, pyrodex needs good containment to ensure all/most of the charge ignites. Install the ematch and add the pyrodex charge make sure the ematch head is submerged/touching the pyrodex. I then pack the remaining ejection canister void 'snugly' with dog barf, two crosses of electrical tape over the end and two wraps around the circumference. Works like a charm
O did we say groundtest with all the recovery items installed as for a flight, very important..
 

WillMarchant

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I use the PerfectFlite MAWD and ALWAYS ground test when I switch ematch or build a new rocket.
Ground test is the most important prep for successful recovery imho.
I just wanted to extract this nugget from John's post. It would be difficult to overstate the importance of the "test before you fly" concept.
 

Pantherjon

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That is how I do mine too!:eyepop: With 2 minor differences..I use a section of drinking straw instead of the AT ignitor tubes(hey, when going cheap, go all out as the straws are FREE at McD's!:roll:), and I use a multi meter to test for continuity of the filament after nipping the tip off..I tried using an Estes controller but every time I put the key in to test continuity *poof* there went the filament!:confused:
 

cobra1336

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I use Newton's 3rd Rocketry canisters. Very simple to use.

ecanlarge.jpg
 

quickburst

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I wish TRA, NAR could get an exception to policy on black powder and matches for rocketry.
I think this day is coming. I also think it will come sometime in the near future.

No permit?
Use the permit free products available from many of the vendors, or do as Scott (K&S Rockets describes). There are always options available.
1.) No, you do not need a permit to purchase Black Powder.
2.) The ATF can fine you for possessing black powder.
3.) I don't know of a single rocketeer that has been arrested or fined for using black powder.

I have never been hit by a meteor, golf ball, beer truck, asteroid or lightning .... but all of these these things are possible.
 

Handeman

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All of these posts have good advice. I think the top items are:

  1. Use low current ematches, NOT igniters. Igniters are designed to light motors with 12VDC systems.
  2. Always ground test first.
  3. Test the charge along with the ignition system.

I use xmas lights, homemade ematches, and commercial ematches. It depends on the rocket, the motor, and the expected flight profile. I don't believe there is one perfect solution, just some that are better then other in certain situations/conditions.
 

Luv2launch

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thanks for all the input all! One other question...do I need a permit to get the 4F black powder for these charges?

Matt
Considering you live in Ma you will probably have a hard time getting BP with some form of gun permit.I went down to CT and picked up some Hodgden pyrodex that if contained right will work great as an ejection charge.I used the cardboard tube off a coat hanger and Quest Q2G2 igniters for my first DD try.I epoxied a piece of cardboard to the bottom and made a hole big enough for the igniter to go through and sealed that with epoxy then filled the amount of powder I needed put some recovery wadding on top of that to keep it in place then epoxied another piece of cardboard on top of that then wrapped it all in a couple layers of electrical tape.It made for a very robust ejection charge.Now if I can only figure out why my RCC2 mini blew both charges at the top I will be ok.It was set for all the default settings I checked before and after the flight.
 

Mikus

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I wish TRA, NAR could get an exception to policy on black powder and matches for rocketry.

Me too. It's stupid that I can have pounds of the stuff for firearm usage but not even a gram for model rocketry. :y:
 

Adrian A

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Considering you live in Ma you will probably have a hard time getting BP with some form of gun permit.I went down to CT and picked up some Hodgden pyrodex that if contained right will work great as an ejection charge.I used the cardboard tube off a coat hanger and Quest Q2G2 igniters for my first DD try.I epoxied a piece of cardboard to the bottom and made a hole big enough for the igniter to go through and sealed that with epoxy then filled the amount of powder I needed put some recovery wadding on top of that to keep it in place then epoxied another piece of cardboard on top of that then wrapped it all in a couple layers of electrical tape.It made for a very robust ejection charge.Now if I can only figure out why my RCC2 mini blew both charges at the top I will be ok.It was set for all the default settings I checked before and after the flight.
I used to use a similar method (you can skip the cardboard end caps and just use epoxy across the ends if you want), but I have since switched to using surgical tube with a zip tie at each end. Both methods will ignite Pyrodex reliably, but the surgical tube method has the advantages of being proven to work at high altitudes (>25kft+ ASL), it's a little quicker and easier, and you don't need to make them ahead of time. The Canadians have an exemption for BP for ejection charges now that requires that the charges are made on-site. The only downside is that the surgical tube method is slightly bulkier. And this is another vote for using Q2G2s for ejection charges. They're in effect a low-current ematch labeled as an ignitor.
 

Adrian A

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Me too. It's stupid that I can have pounds of the stuff for firearm usage but not even a gram for model rocketry. :y:
I also find it ironic that it's allowed for use in a tool designed specifically to kill people, but not for the application of allowing a hobby rocket to land more gently.
 

Handeman

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I have been hearing that some of the BATFE agents doing LEUP inspections are stating that they interpret the following:

“...the black powder is intended to be used solely for sporting, recreational, or cultural purposes in antique firearms, as defined in 18 U.S.C. 921(a)(16) or antique devices, as exempted from the term "destructive devices" in 18 U.S.C. 921(a)(4).”

to mean that BP can be used for sporting purposes,
AND BP can be used for recreational purposes,
AND BP can be used for cultural purposes in antique firearms, ....

If that is the interpretation that is used, rocketry would fall under recreational purposes and would be exempt up to 50lbs.

Of course other people have talked to agents that say BP can only be used in antique firearms or by permitees.

I think that the problem is the same problem we've always had with the BATFE, they have not and will not come out with a clear and stated interpretation that all agents will stick by.
 

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