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- Jan 19, 2019
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Haven’t found time yet to test. Hopefully soon...
9k' should not be a problem - still plenty of oxygen at that altitude to support the combustion. I'm curious to hear from those experienced in high altitude flights where you make the transition from BP to a CO2 system though!I’d like to hear more about problems with bp at high altitudes or if anything needs to be adjusted or changed such as a different amount of bp or anything. I’m planning to fly up to 9k for the first time in the near future, weather permitting. Is there anything I need to do differently for a flight that high? Not sure if that’s even considered high altitude yet? So far I haven’t flown over about 3,400’. As long as ground tests are good, then everything should be fine?
Try this.
https://www.rocketryforum.com/attac...itude-deployment-charges_may-2013-pdf.286528/
I found that putting the BP in first. Inserting the igniter a very short distance into the powder then packing dog barf in tightly and taping it closed with several layers of duct tape, I was able to get consistent, repeatable results. Putting the igniter all the way to the bottom of the charge well gave inconsistent results with unburned powder scattered inside the airframe and on the nomex blankets.
Try this.
https://www.rocketryforum.com/attac...itude-deployment-charges_may-2013-pdf.286528/
I found that putting the BP in first. Inserting the igniter a very short distance into the powder then packing dog barf in tightly and taping it closed with several layers of duct tape, I was able to get consistent, repeatable results. Putting the igniter all the way to the bottom of the charge well gave inconsistent results with unburned powder scattered inside the airframe and on the nomex blankets.
I will have to disagree in the friendliest way I can. With redundant altimeters especially the primary should be as close to your calculated size that you can get. If that doesnt open your rocket up something is jammed and bad things are about to happen. The backup charge should be big enough to "Blow it out or blow it up". 25% bigger seems very reasonable to me. I have never seen this size charge actually damage anything. Just for the sake of argument let say it blows the body tube apart at the coupler. The 2 sections will still be attached to the recovery harness and rate of descent will be acceptable. To blow it to pieces would require a huge amount of powder, not an extra 25%. A ballistic recovery is the worst possible scenario, anything else is preferable including "pieces raining down"Blow it out or blow it up is poor methodology when you have the time and the tools to get it right.
+25% is a HUGE step up.
Make sure you ground test it, too. The last thing that you want at altitude other than a charge that doesn't go off resulting in one falling object is one that destroys your rocket or separates all the pieces from each other and creates multiple falling objects.
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