Black powder amounts

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jim fustini

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I just ground tested my first duel deploy. The main chute section is 5.38 x 25". the ejection charge canisters are mounted on each end of the bay. I am using a Hialt45 perfectflite. I put 2.50 grams of fff Goex in the cans, applied vacuum and it blew the nose cone off and about 5' of harness no laundry. The cans will only hold another gram they are PML's . I would like to use shear pins on the nose cone. How much more powder should I use? I can buy or make bigger canisters.
 

MarkM

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TEST IT!

You'll probably need another 1/2 -1 g, depending on the type of shear pins you use. Also, you should always ground test in a flight-ready configuration...that means with all recovery gear, including chutes, loaded up.
 

jim fustini

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TEST IT!

You'll probably need another 1/2 -1 g, depending on the type of shear pins you use. Also, you should always ground test in a flight-ready configuration...that means with all recovery gear, including chutes, loaded up.
Laundry ie ( MAIN CHUTE ,Nomex blanket) that is all the recovery gear. (besides the booster harness) going drogueless. I have the pins and holes in the nose cone done, I just did'nt think the powder seemed the right amount and I wanted to test it without them first. To see where I'm at, then add a little more. 2 1/2 gms. did'nt even push the chute out plus another 20 feet of harness. The pins are 2-56
 

Handeman

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Laundry ie ( MAIN CHUTE ,Nomex blanket) that is all the recovery gear. (besides the booster harness) going drogueless. I have the pins and holes in the nose cone done, I just did'nt think the powder seemed the right amount and I wanted to test it without them first. To see where I'm at, then add a little more. 2 1/2 gms. did'nt even push the chute out plus another 20 feet of harness. The pins are 2-56
The ejection charge isn't intended to push the laundry out, unless you are using a piston. All the charge is supposed to do is pressurize the tube so the nose cone will pop off.

If you want the laundry out, you need to put it on top of the shock cord so when the nose cone leaves the tube, it pulls the laundry out with the shock cord, OR, have the nose cone pull a drouge out that pulls the laundry out. Either way, you need to use enough charge to have the nose cone pop off with enough force to pull the recovery out with it.
 

rdmmdr

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don't attach the recovery harness. double the charge load and blow the nose cone over the house. if you can clear a two story house with the nose cone then you know you have enough powder. you just might need more shock cord.
 

Chrisn

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what if the 2 story house is really big?
 

jim fustini

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don't attach the recovery harness. double the charge load and blow the nose cone over the house. if you can clear a two story house with the nose cone then you know you have enough powder. you just might need more shock cord.
YEAH, Ok I guess I'll ask someone over at Rocketry planet.
 

Chrisn

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They will also be allowed to give you some good black powder formulas to use
 
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