Ejection Charge Canister / Ejection Carge / Tripple 7 FFFG Black Powder

Greeting fellow rocketeers,

Background: I am building a 4 1/2 in HV ARCAS Carbon Fiber rocket with duel deployment system. I am using an M2500 T AeroTech Motor. Open rocket estimates altitude of 18,000 ft. AGL. I am using a feather light Rav3 for the
on board computer that will be initiating the injection charge. I am using a 24in Dura Chute for a drogue and a 120 in Dura Chute for the main deployment.

1) I have FFFG Triple 7 black powder from Bass Pro Shop here in California. I see a lot of guys here are using FFFF powder, while I could only get my hands on FFFG powder. What is the difference? Has anyone used this product and how will it change my ejection charge calculations if any??? :surprised: .

2) What type of or size ejection charge canister, grams of powder should I use and what do you think a good calculation would be for the size of ejection canister and the type of powder I am using. 4 1/2 in diameter rocket x 24 in area for the drogue chute and 4 1/2 inch x 12 in area for the main chute. If anyone can recommend a reliable easy to install ejection canister I would appreciate it.

3) Sheer pins? What type of sheer pins do you think I should use based upon diameter of rocket 4 1/2 in Carbon Fiber, size of ejection canisters, and black powder charge? Someone had suggested either 2-56 Nylon screws or 4-40 Nylon screws. If you think there is a better type of sheer pin or brand then one mentioned please enlighten me.

If any one has anything POSITIVE to add or could recommend anything that will help me bring this money pit back to earth safely then please help me. :wink:

Thank you.... Hope I get some good info from some of those sharp minds out there.

There seems to be a concern about if I am an L3 Cert. No I am not as of yet. I will be going for my L3 cert later this summer. I am just in the process of collecting info and buying parts. I am fully aware that I need to be an L3 cert to buy a motor. That's what this forum is for right? Research and knowledge... Thanks to those of you with concerns. There is nothing in the rules that says I can't get the parts ready and do my research prior to my L3 build. When I am ready and have a TAP advisor then I will get the motor with their approval. Thanks guys and gals...

Triple 7 is not black powder. It is a black powder substitute. https://www.hodgdon.com/tripleseven.html It burns much slower than BP but is more energetic. It works great in BP firearms but is far from ideal for rocket recovery.

FFFFG black powder is the preferred size of bp particles for ejection, however FFFG black powder particles are only slightly larger. The larger particles take a little longer to burn out, but as it is real bp, is still burns faster any bp substitute, and is much preferred to any kind of BP substitute such as Pyrodex(R) or Triple 7(R).

BP substitutes can be made to work, but they must be confined in a container to insure all the particles are ignited before the container releases them.

Bob

Yes, it matters. There are online calculators for shear pins and ejection charges both.

HTH,
-dh.

Ahhh, me thinks you need to certify level 3. You can't get or fly the motor until you do.
I'm not certain from your question that you are.
Consider reviewing https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3718748/
Might also want to get "Modern High Powered Rocketry 2" and give it a read.

cbrarick said:

Ahhh, me thinks you need to certify level 3. You can't get or fly the motor until you do.
I'm not certain from your question that you are.
Consider reviewing https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3718748/
Might also want to get "Modern High Powered Rocketry 2" and give it a read.

Click to expand...

Is that NIH.Gov URL correct? I don't see the relevance.

dhbarr said:

Black Powder Grades & Equivalent Sizes (in mm)
Sporting Grades (G)	Grain Size (in mm)	Blasting Grades (A)	Grain Size (in mm)
		1FA	8.0-4.0
Cannon Grade	4.76-1.68	2FA	4.76-1.68
1FG	1.68-1.19	4FA	1.68-.84
2FG	1.19-.59
3FG	.84-.29	5FA	.84-.297
4FG	.42-.15	7FA	.42-.149
		Meal D	.42
5FG	.149	Fine	.149

Yes, it matters. There are online calculators for shear pins and ejection charges both.

HTH,
-dh.

Click to expand...

Thanks for the info... I appreciate it...

thanks Bob...

cbrarick said:

Ahhh, me thinks you need to certify level 3. You can't get or fly the motor until you do.
I'm not certain from your question that you are.
Consider reviewing https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3718748/
Might also want to get "Modern High Powered Rocketry 2" and give it a read.

Click to expand...

Ahhh me thinks you are right....

There seems to be a concern about if I am an L3 Cert. No I am not as of yet. I will be going for my L3 cert later this summer. I am just in the process of collecting info and buying parts. I am fully aware that I need to be an L3 cert to buy a motor. That's what this forum is for right? Research and knowledge... Thanks to those of you with concerns. There is nothing in the rules that says I can't get the parts ready and do my research prior to my L3 build. When I am ready and have a TAP advisor then I will get the motor with their approval. Thanks guys and gals...

cbrarick said:

Ahhh, me thinks you need to certify level 3. You can't get or fly the motor until you do.
I'm not certain from your question that you are.
Consider reviewing https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3718748/
Might also want to get "Modern High Powered Rocketry 2" and give it a read.

Click to expand...

Oh BTW.... me thinks you sent the wrong link... you sent this



Thank you for thinking and thank you for trying to help.... If you have any more info that could help it would be great.... :wink:

Worsaer said:

Is that NIH.Gov URL correct? I don't see the relevance.

Click to expand...

There seems to be a concern about if I am an L3 Cert. No I am not as of yet. I will be going for my L3 cert later this summer. I am just in the process of collecting info and buying parts. I am fully aware that I need to be an L3 cert to buy a motor. That's what this forum is for right? Research and knowledge... Thanks to those of you with concerns. There is nothing in the rules that says I can't get the parts ready and do my research prior to my L3 build. When I am ready and have a TAP advisor then I will get the motor with their approval. Thanks guys and gals...

bobkrech said:

Triple 7 is not black powder. It is a black powder substitute. https://www.hodgdon.com/tripleseven.html It burns much slower than BP but is more energetic. It works great in BP firearms but is far from ideal for rocket recovery.

FFFFG black powder is the preferred size of bp particles for ejection, however FFFG black powder particles are only slightly larger. The larger particles take a little longer to burn out, but as it is real bp, is still burns faster any bp substitute, and is much preferred to any kind of BP substitute such as Pyrodex(R) or Triple 7(R).

BP substitutes can be made to work, but they must be confined in a container to insure all the particles are ignited before the container releases them.

Bob

Click to expand...

Awesome info.. thanks BOB...

bobkrech said:

...It (Triple7) works great in BP firearms but is far from ideal for rocket recovery....BP substitutes can be made to work, but they must be confined in a container to insure all the particles are ignited before the container releases them...

Click to expand...

I disagree. I think Triple7 is far better than BP: it is legal to own and use without a LEUP, it does not produce sulphur and other corrosive residues, and it is not a low explosive.

Unless you are using BP for an exempt black powder firearm, the ATF says you need a LEUP to use and possess BP. No such rules apply to Triple7 or other modern firearm propellents.

If you think of the parachute/nosecone as a bullet, the body tube is the barrel. In a firearm, the majority of the powder is burned in the barrel, not the cartridge. The powder burning in the barrel explains why longer barrels produce higher velocity - more of the powder is fully burned before the bullet leaves the barrel producing higher pressure.

If BP is not well contained it also performs poorly. In our case we have the body tube to act as our 'barrel'. Pyrodex and Triple7 do burn more slowly so if used in a larger diameter body tube they greatly benefit from being placed in a longish, small diameter tube shaped charge holder - brass tubing, heavy cardboard, PVC, etc. The small tube creates a directed flame to ignite the airborne particles more quickly. (An aside - latex tubing does not work as well because when it ruptures it allows the remaining unburnt powder to disperse away from the flame front.)

I started reloading in my teens and have studied how firearms propellents work as a result. They really are no different than the propellents we use in our rocket motors. They all require containment to build pressure to propagate ignition. BP is just a lot easier to ignite and burns faster so it is more forgiving.

As long as the ATF keeps looking the other way it's fine to use BP. But someday that may change and having experience with its substitutes will be useful. I am not advocating that anyone start using Triple7 or any other substitute without making sure it works in your configuration. But I have personally witnessed it used by flyers with the same success as BP and after my own testing plan to use it exclusively from now on in my own flights.

As always, your mileage may vary.


Tony

ATF on BP: https://www.atf.gov/explosives/qa/black-powder-subject-regulation-under-federal-explosives-laws

manixFan said:

I disagree. I think Triple7 is far better than BP: it is legal to own and use without a LEUP, it does not produce sulphur and other corrosive residues, and it is not a low explosive.

Unless you are using BP for an exempt black powder firearm, the ATF says you need a LEUP to use and possess BP. No such rules apply to Triple7 or other modern firearm propellents.

If you think of the parachute/nosecone as a bullet, the body tube is the barrel. In a firearm, the majority of the powder is burned in the barrel, not the cartridge. The powder burning in the barrel explains why longer barrels produce higher velocity - more of the powder is fully burned before the bullet leaves the barrel producing higher pressure.

If BP is not well contained it also performs poorly. In our case we have the body tube to act as our 'barrel'. Pyrodex and Triple7 do burn more slowly so if used in a larger diameter body tube they greatly benefit from being placed in a longish, small diameter tube shaped charge holder - brass tubing, heavy cardboard, PVC, etc. The small tube creates a directed flame to ignite the airborne particles more quickly. (An aside - latex tubing does not work as well because when it ruptures it allows the remaining unburnt powder to disperse away from the flame front.)

I started reloading in my teens and have studied how firearms propellents work as a result. They really are no different than the propellents we use in our rocket motors. They all require containment to build pressure to propagate ignition. BP is just a lot easier to ignite and burns faster so it is more forgiving.

As long as the ATF keeps looking the other way it's fine to use BP. But someday that may change and having experience with its substitutes will be useful. I am not advocating that anyone start using Triple7 or any other substitute without making sure it works in your configuration. But I have personally witnessed it used by flyers with the same success as BP and after my own testing plan to use it exclusively from now on in my own flights.

As always, your mileage may vary.


Tony

ATF on BP: https://www.atf.gov/explosives/qa/black-powder-subject-regulation-under-federal-explosives-laws

Click to expand...

Actually BP substitutes fall under the same regs as BP, do a search for some of the other BP threads specifically looking for posts by Bob Krech. I used to think the same thing as you.

Just so Bob doesn't have to repost the link here is his reply in post #17: https://www.rocketryforum.com/showthread.php?120331-Containing-Smokeless-Powders&highlight=pyrodex
And another about this subject: https://www.rocketryforum.com/showthread.php?120331-Containing-Smokeless-Powders&highlight=pyrodex

And the search I used to find them. https://www.rocketryforum.com/search.php?searchid=4573658

I appreciate it guys.. lots of info here.... thank you very much.... keep checking in ... I have a ton more questions... next week I am going to try to build an AV bay...

rharshberger said:

Actually BP substitutes fall under the same regs as BP, do a search for some of the other BP threads specifically looking for posts by Bob Krech. I used to think the same thing as you.

Just so Bob doesn't have to repost the link here is his reply in post #17: https://www.rocketryforum.com/showthread.php?120331-Containing-Smokeless-Powders&highlight=pyrodex
And another about this subject: https://www.rocketryforum.com/showthread.php?120331-Containing-Smokeless-Powders&highlight=pyrodex

And the search I used to find them. https://www.rocketryforum.com/search.php?searchid=4573658

Click to expand...

That is incorrect. BP substitutes and smokeless powders do NOT fall under the same regs as to BP. Read the link I posted and you'll see it was updated on Feb. 16, 2016. It is up to date and would include any changes made to the regs. I stand by my statement that Triple7 is not regulated like BP.

If you follow Bob's reasoning in this post:

https://www.rocketryforum.com/showt...ining-Smokeless-Powders&p=1384035#post1384035

he says:

"BP and its substitutes and smokeless powders by law are not regulated by BATFE if you purchase them for hunting and/or reloading up to a 50 pound quantity. In most states, if you are a hunter or reloader, you can legally purchase any of these propellants without a federal explosive permit, and if you're not a hunter or shooter, in some states you will need to show a BATFE permit/license to purchase them legally"

That is inaccurate as that is not what the exemption says. The exemption as written ONLY applies to BP, not to smokeless powder or BP substitutes. Smokeless powders and BP substitutes are exempt because an exemption for small arms components is written into the same Federal law we are discussing:

https://www.law.cornell.edu/uscode/text/18/845

"this chapter shall not apply to:"...."(4) small arms ammunition and components thereof;"

So the ATF CANNOT by Federal statute regulate smokeless powder or PB substitutes as explosives as they are clearly a component of small arms ammunition. (BP on the other hand has always been considered a low explosive.) Unless Bob has proof to the contrary, there aren't any states that require a BATFE permit to buy BP or smokeless powders. Some jurisdictions may regulate the sale and storage, but none require a BATFE permit that I have been able to find. They may require some other kind of ID card however.

But they are on the list of explosives. What is the point of that if the ATF can't regulate them? If you continue to read the law, you'll see the list of explosives as defined by the ATF is also used for section 844 which says if you use an explosive for evil intent you are in big trouble:

https://www.law.cornell.edu/uscode/text/18/844

specifically subsections (d), (e), (f), (g), (h), and (i).

So smokeless powder and BP substitutes are on the list of explosives for the purpose of what can be considered an explosive during the commission of a crime, not because you now need an LEUP to use it. If you aren't committing a crime with smokeless powders or BP substitutes, you are exempt from regulation.

I have an FFL and had asked my AFT examiner about BP and its substitutes in the past which is where I got my information. I called her today so I could get reconfirmation. But of course she is out of the office until next week. Anyone is free to call the ATF and verify my statements.

I realize that it may seem unfair to some that I am taking issue with Bob even though he has not directly posted in this thread. But as rharshberger referenced him as the source of his information, it only makes sense for me to go to that source. I have read many of Bob's posts on electronics and he clearly is very knowledgeable and contributes greatly to this board. But in this instance I think he's mistaken in his conclusions.

I am not trying to change anybody's mind about using Triple7 or any other powder. I am just responding to what I see as misinformation about a particular set of products.


Tony

If you keep your BP somewhere that is not in plain sight, and you don't do anything stupid with it, then you are also protected from illegal search and seizure. No one will be coming into your house or garage to see if you have BP hiding there.