clustering composites

[stevem]

I see lots of info in BP clutering - what about AP?

How hard is to cluster them?

I am thinking about building a rocket that would fly on a pair of 24mm F21s but I need to understand the whys and wherefores of AP clusters.

 

[cls]

Hi Steve, I have had excellent reliability clustering 3x F21s and 3xF20s using "FireFly" ignitors. I get them from Performance Hobbies, they are about $1 each. with those ignitors, it's just as easy as clustering BP.

they are low resistance and so three in parallel may take more current than the "average" 12v system can deliver.

with larger APCP motors, people do stuff like putting two ignitors in, adding slivers of thermalite or blue thunder propellent, super double dipping secret ignitor formula ... but you don't need any of that for a pair of F21s.

HTH!

 

[stevem]

thanks cls - that helps.

 

[lalligood]

Check out the Twiggy ignitors from Quickburst too... I have been using them for a while now & have had a 100% successful rate on ignitions. I think they would work great for AP clusters too. 10 pack will set you back $10.

HTH,

 

[n3tjm]

The absolute best igniter to use for clustering (or any other application) is magnelite. I have used Twiggys and Fireflys, and must say that I am disapointed with them. Twiggys work when they fire... Fireflys do not have that much umph when fired compaired to magnelite. Also, none of my Quick Burst or Firefly igniters still work... they don't have a very long shelf life... while Magnelites last forever.

 

[stevem]

n3tjm- how hard is it to come by magnelite? to be honest, I don't really know what it is

 

[BlueNinja]

You can get it from Rocketflite. I get mine from Science Education Center, but that's cause he's more local than Rocketflite. The stuff's kinda expensive, but it pays off.

 

[rabidsheeep]

quick question, do you have to use the wires they sell or can you just use normal guage wires?

 

[n3tjm]

You can use it on any wires. Their wires, homemade wires, estes, aerotech, daveyfire ingniters... the posibilities are endless.

 

[solrules]

Daveyfire -F igniters dipped in magnelite pyrogen, with a little sliver of a cut up blue thunder propellant in the forward grain and a powerful relay system is an almost sure way of igniting composite clusters.

Then, there is always Cupric oxide thermite for the big stuff.........

 

[n3tjm]

ML-12's, no-fold, dipped igniters work very well. Never had a ignition falilure clustering with these igniters. At NSL 2003, my largest (in number, not TI) cluster was fired. Seven G35's in my American Spirit.

It also should be noted that some propellants are better left alone when clustering:

Redline, Red Rhino, Green Gorilla for example. They are notouriously hard to start.

Also, bigger motors take longer to start than smaller motors.

 

[YvesLacombe]

I just use thermalite with teflon sheathing to do airstarts

I still have two old CXA rolls left from 10 years ago (30 feet each).

Heh

- Yves