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Shear pins w/o altimeter

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kelltym88

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Maybe this is not worded correctly. Anyway, I've launched my upscale Manta Bomber only 2 times. Each time resulted in damage to the lower pod sections. Now I want to make it so that they come down on their own.

My question is: Will the ejection charge in a 29mm motor be strong enough to separate the tubes from the rocket with shear pins? I have NO electronics on board.

My plan is to make a bulk head at the tube coupler point, and have a baffle in the lower section. When the charge fires, it should separate at the coupler. I'll have to rig some kind of line so that when it separates, it will help pull out the 'chute.
 

JoeG

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depends on how much powder you use.

I sometimes only use some of the powder included with the motor if the tube is short and minimum diameter. Using the same motor in a longer four inch rocket would necessitate using all of the powder supplied or even enhancing the charge with additional BP.

Ground testing to determine the proper amount of charge would be a good idea.
 

SpartaChris

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I would ground test. If you have a motor, take the BP that comes with the kit and pour it into a cup on a scale to figure out how much comes with the reload. Then, measure that amount separately and put it into the fingertip of a latex glove or something with an e-match. Run the e-match through the hole in the well of the motor and you're set.

If you need to increase the charge, you can do so by making the well larger using some masking tape. Wrap some tape along the outside of the well to increase it's depth so it can hold more ejection powder. When you have the amount you want, stuff some dog barf over the top and fold it over. Put a layer or two over the top and you're set.
 

kelltym88

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I would ground test. If you have a motor, take the BP that comes with the kit and pour it into a cup on a scale to figure out how much comes with the reload. Then, measure that amount separately and put it into the fingertip of a latex glove or something with an e-match. Run the e-match through the hole in the well of the motor and you're set.

If you need to increase the charge, you can do so by making the well larger using some masking tape. Wrap some tape along the outside of the well to increase it's depth so it can hold more ejection powder. When you have the amount you want, stuff some dog barf over the top and fold it over. Put a layer or two over the top and you're set.
I like this idea, Chris. A Fat Tire for you. :cheers: But:

Can I just use an igniter?


Where can I get some FFFFE powder? I've tried a couple local gunshops.
 
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DAllen

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I like this idea, Chris. A Fat Tire for you. :cheers: But:

Can I just use an igniter?


Where can I get some FFFFE powder? I've tried a couple local gunshops.
FFFg or FFFFg will also work. But I wish you best of luck finding some BP. I had to search far and wide to get some. :mad: And that is in Michigan where there are oodles of muzzle loading hunters out there.

Someone needs to develop a reliable way to use Pyrodex because I seriously doubt BP is going to continue to be available over the next few years.

-Dave
 

blackjack2564

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FYI.....AT hobby 29mm motors [G-64 etc,] come with .75 grams of bp and high power 29's and 38's come with 1.4 grams
 

Handeman

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FFFg or FFFFg will also work. But I wish you best of luck finding some BP. I had to search far and wide to get some. :mad: And that is in Michigan where there are oodles of muzzle loading hunters out there.

Someone needs to develop a reliable way to use Pyrodex because I seriously doubt BP is going to continue to be available over the next few years.

-Dave
I don't know about Michigan, but here in Virginia I get my FFFFg GOEX BP at the Gander Mountian store. $14.99 for a 1 lb can.
 

ben_ullman

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FFFg or FFFFg will also work. But I wish you best of luck finding some BP. I had to search far and wide to get some. :mad: And that is in Michigan where there are oodles of muzzle loading hunters out there.

Someone needs to develop a reliable way to use Pyrodex because I seriously doubt BP is going to continue to be available over the next few years.

-Dave
all I use it Pyrodex. Mainly because I got 5lbs free from a guy. I use it for all of my ejection charges.

And Bp won't be going anywhere. Its used in fireworks like AP is to rockets.

Ben
 

RandyM

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FFFg or FFFFg will also work. But I wish you best of luck finding some BP. I had to search far and wide to get some. :mad: And that is in Michigan where there are oodles of muzzle loading hunters out there.

Someone needs to develop a reliable way to use Pyrodex because I seriously doubt BP is going to continue to be available over the next few years.

-Dave
Here's an option to getting BP. You have to order 5 lbs. at a time, but either go in with a few others to buy it or just get a lifetime supply in one package!:jaw:

http://www.powderinc.com/
 

shoitsma_86

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Pyrodex is easy to use, you just have to pack it very tightly. I only use Pyrodex for ejection charges and have had great, consistent results. It did take a fair amount of ground testing to arrive at consistent reliable results, but I'll share my trials here so you don't have to go through what I did.

I used the MF-12 e-matchesfrom Rocketflite, but not dipped in Pyrogen. Basically its just 26awg lead wire stripped on the ends with very thin (40ish awg) nichrome wire bridged across the leads, so you can make these yourself if you don't want to buy the premade ones.

I cut pants-hanger tubes into 2" lengths, and put a piece of masking tape over one end, and punched a small hole through it with a paperclip. I fed the e-match tip through this hole and out the other (open) end of the tube so it was sticking out about an inch. Then I poured 5 minute epoxy into the open end of the tube so it filled up about 1/8".

After it dried i removed the masking tape. This end of hte tube is now sealed and the ematch is held in place. Then i just measured and poured the FFFg Pyrodex into the open end, and folded the e-match tip down into the powder so it was buried. Then i packed dog barf in on top extremely tight using a ball point pen until the tube was filled to the top, and then i sealed it with 2 layers of electrical tape.

This method has proven extremely reliable for me. The trick is a tight seal on both ends, packing the powder very tightly, and ensuring full contact of the nichrome bridge with the powder.







 

epickett

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FFFg or FFFFg will also work. But I wish you best of luck finding some BP. I had to search far and wide to get some. :mad: And that is in Michigan where there are oodles of muzzle loading hunters out there.

Someone needs to develop a reliable way to use Pyrodex because I seriously doubt BP is going to continue to be available over the next few years.

-Dave
Cabellas, Dave. Is there one near you?

Eldred
 
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