Clustering Composites and BP Motors

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Marsman

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I am trying to build a Delta IV model using an Apogee E9 or F10 long burn and two Estes C11s on the outboard parrallel-staged boosters. Using a Go-Box or an Interlock controller, what is the best method for clustering these 3 motors?

Also, I have gap-staged Estes BP motors using the ejection charge of the lower stage to ignite the upper stage motor. If I use an Aerotech F-20 to ignite a black powder D-12, with the Aerotech's ejection charge ignite the upper stage just as 2 BP motors would?
 
BP motors will ignite easier and faster than composite motors will. Make sure you have enough amperage to supply the igniters or you may not ignite the F10.

As for the gap staging, I have not done this but in my thinking, I wouldn't trust the ejection charge to ignite it. You could possibly use a timer for your sustainer. Try this one: https://68.178.208.82/cgi/PF_Store/...page&thispage=microT2.html&ORDER_ID=197114930

Just my $.01
 
Ditto what bigone posted!
Don't mix BP and Composite motors in the same stage.. Your just bagging for a mishap. stick to all one or the other for the stage.
I only fly BP clusters with relay ignition systems but that's given me more then a 99+% success rate over the past 30 some years. So that's the only method I practice or suggest.
Most important is to pre and post installation TEST each and every Igniter. I can't begin to tell you the number of brand new out of the bag or motor pack BAD igniters I've found over the last couple years. The little testor below is a cluster saver for sure:)

Upper stages if your going to use APCP should be electronically ignited as well.

L-Offs-Photos-01-sm-Clusters&SatV.jpg
 
I was thinking that that was going to be the problem; the BPs would ignite beofre the composites. What if I wire the Composite engine to one controller and the BPs to another and set the composite off fractionally before the BPs? I am thinking that since the F10 burns for 8 seconds, what if I make the rocket heavy enough that it won't leave the pad fast enough or at all before the BPs ignite...

Won't the composite ejection charge ignite the black powder motor if the black powder ejection charges ignite the motors (I tested this)? Basically what I am asking is are the BP ejection charges made from the same material as the composite ejection charges?
 
I was thinking that that was going to be the problem; the BPs would ignite beofre the composites. What if I wire the Composite engine to one controller and the BPs to another and set the composite off fractionally before the BPs? I am thinking that since the F10 burns for 8 seconds, what if I make the rocket heavy enough that it won't leave the pad fast enough or at all before the BPs ignite...

Won't the composite ejection charge ignite the black powder motor if the black powder ejection charges ignite the motors (I tested this)? Basically what I am asking is are the BP ejection charges made from the same material as the composite ejection charges?

Composite motor ejection charges use, I am pretty sure, ffffg BP. I am not sure about estes type motors. I think they have a slug type charge.

Why not just use a central F10 and two outboard F12Js? That would give you plenty of smoke. As for igniting the sustainer, I'm not sure I would 100% trust the ejection charge to ignite the propellant. The Perfectflite timer I posted earlier is small enough to fit into a 24mm MMT tube and you can use a 9v battery to power it to ignite the sustainer motor. The timer is programmable from .6 seconds to over 60 seconds in .1 second increments. Use a simulation program like rocksim to figure out how much time to set it to and you won't have to worry about gap staging. I would hate to see you lawn dart it due to a non-ignition.

Hope this helps.

Could you post any plans, photos, etc. on your rocket?
 
Composite motor ejection charges use, I am pretty sure, ffffg BP. I am not sure about estes type motors. I think they have a slug type charge.

Why not just use a central F10 and two outboard F12Js? That would give you plenty of smoke. As for igniting the sustainer, I'm not sure I would 100% trust the ejection charge to ignite the propellant. The Perfectflite timer I posted earlier is small enough to fit into a 24mm MMT tube and you can use a 9v battery to power it to ignite the sustainer motor. The timer is programmable from .6 seconds to over 60 seconds in .1 second increments. Use a simulation program like rocksim to figure out how much time to set it to and you won't have to worry about gap staging. I would hate to see you lawn dart it due to a non-ignition.

Hope this helps.

Could you post any plans, photos, etc. on your rocket?

Thanks

It's actually two seperate projects-the Delta IV and the 2 stager. I use the term Delta IV just to describe the configuration- I want to try a vehicle with two pop off boosters before I try an actual scale model.

Delta IV- I'm on a limited budget, so I'm trying to keep this simple. 3 Composite motors will be expensive, especially considering that I don't have any RMS hardware yet- any composites will be single use. Maybe I will have to go all BP.

2 Stager- Ok, if I go with the timer, how do I connect it to the upper stage engine be it a BP or composite? Basically, I know that I have to hook in a battery, but what do I use for an igniter? I want to avoid making my own as simplicity is golden here.
I'll see if I can post my plans a bit later.
 
marsman:
We can lead the horse to water but until you've crashed it sound like your not going to listen.
Mix propellant at your own risk, I can all but assure your setting yourself up for a cluster failure, NO MATTER WHAT SCHEME YOU divise. You MIGHT get away with it once, but sooner or later that darn CP isn't going to burn and your gonna crash. Is all that time and effort in building, detailing and finishing your Scale model worth the risk? Only you can decide. I'd caution you to seriously reconsider and Stick to BP for you clustering enjoyment. I have the Apogee Delta-III which I plan on clustering but will be using ONLY BP motors.
Good luck with whatever you end up doing.
 
marsman:
We can lead the horse to water but until you've crashed it sound like your not going to listen.
Mix propellant at your own risk, I can all but assure your setting yourself up for a cluster failure, NO MATTER WHAT SCHEME YOU divise. You MIGHT get away with it once, but sooner or later that darn CP isn't going to burn and your gonna crash. Is all that time and effort in building, detailing and finishing your Scale model worth the risk? Only you can decide. I'd caution you to seriously reconsider and Stick to BP for you clustering enjoyment. I have the Apogee Delta-III which I plan on clustering but will be using ONLY BP motors.
Good luck with whatever you end up doing.


Sorry for any misunderstanding. I'm not going to try to mix composite and BP. I'm probably going to go all BP. My new question pertains to my 2 stage rocket that I asked about in my previous post. I am going to try the timer reccommended above, but I don't know whic igniter I should use to light the engine.
 
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