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skyward

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Hello, I am new to rocketry. I have built a Sonic 2200 (Has discontinuous staging) and am stuck on the ignition of the Second Stage. I simply don't understand how the second stage is ignited or the timing involved. Plus, with a Bulk Head in the couplers of both payload sections how would any wires even get close to igniting the engine. (I was planing on using Estes F18's). I called Apogee and they had no idea how any of this would work. They could only help me with direct staging.(I must say they were very very nice!) I am very frustrated and feel defeated. Any suggestions would be greatly appreciated. Also, I would like to do this as cheaply as possible. Thanks!:facepalm:
 

rstaff3

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I tried a quick search and found a thread from 2005. There, USR mentioned using thermalite fuse to ignite the sustainer. This is a regulated item and is generally not used much these days. Others have mentioned that the payload would have to be modified to accept electronics capable of igniting the sustainer. I assume the builder has to rig a way to get the wires to the business end.
 

Nytrunner

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http://www.rocketryforum.com/showthread.php?17397-Sonic-2200-Staging-Question

Found this link. Looks like that kit requires some modification to be staged electronically. Depending on how far along you are with the build, you may have a good deal of work ahead of you to install a staging timer.

I haven't attempted electronic staging, but even recovery electronics require some careful thought and planning to implement.
 

skyward

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Thanks for the quick response. Yup, I too saw the fuse which is not an option for me. No instruction specific for this model on modifications. I'm not even sure what type of electronics could be used if somehow I did modify it.
 

rstaff3

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I'm not sure what small altimeters detect burnout these days. My G-Wiz does. You could also look at a staging timer. For quick and dirty applications, I have run two simple screws out of the lower bulkhead. The top/inside has wires that are long enough to reach out of the bay so you can hook them to the altimeter. Then, an ematch/igniter is attached on the outside, wrapped on and a wing-nut holding them down. You'd have to plan for a conduit through the rings (or outside the body) to get the wires to the motor.
 

rstaff3

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How far apart are the stages? Maybe you could modify it for normal gap staging? Might need to extend the motor tube in the booster, drill vent holes, etc. I'd also check that the booster isn't naturally stable on the way down.
 

aerostadt

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I had a piston-stager model from US Rockets as I recall. There was a long distance between the first and second stage and actually a piston in between. The directions did not give any instruction, but I surmised that the second stage was ignited by an external fuse probably thermalite. I developed my on electronic staging compartment and documented it on Rocket Reviews. I noticed later that Apogee came up with a better electronic staging method on their website.
 

neil_w

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Jerry Irvine is active on YORF, you might try asking over there...
 

skyward

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Thanks guys for your suggestions. I'll work on it this weekend and let you know how it goes.
 

skyward

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Okay, I bought a PerfectFlite miniTimer4 and was wondering if I should have the timer begin from time of burnout or timing from ignition. I am using two Estes F15-8 engines. Also, how many seconds do I set it for? I'll gladly look up these answers if someone can just point me in the right direction. As always thanks. I am trying to get it ready for a Thanksgiving Launch.
 

rstaff3

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Have you simmed it? Rocketreviews.com has a file but I don't know if it is the same version that's around now. From what I see it is long and the F15 is a mild motor so it may tend to weather cock during boost. I would set the timer to start at launch detect and fire the sustainer at 3.5 sec. which is nominally the burn time. If it's going to coast straight up for a known period, then the timer could be longer.

But then, I've only staged BP to BP the old fashioned way.
 

skyward

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Again thanks for the quick response. I will set it for 3.5 seconds from launch unless anyone else feels it's unwise or has other suggestions. All input is greatly appreciated!
 
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