Clustering composites question

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John Taylor

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I often cluster24mm and 29mm motors up to four G138T. I have stuck with Blue Thunder propellent and have been using Rocketflite.com Clusterfire pyrogen and low current igniters. I have had 100% success with this combination.
I want to be able to cluster other propellents like White Lightning. I have been reluctant to go there because when I have tried in the far past I had one or two motors fail to ignite.
I know people cluster White Lightning often with success.
What are the tips to insure ignition of all motors in a cluster?
 

NOLA_BAR

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I often cluster24mm and 29mm motors up to four G138T. I have stuck with Blue Thunder propellent and have been using Rocketflite.com Clusterfire pyrogen and low current igniters. I have had 100% success with this combination.
I want to be able to cluster other propellents like White Lightning. I have been reluctant to go there because when I have tried in the far past I had one or two motors fail to ignite.
I know people cluster White Lightning often with success.
What are the tips to insure ignition of all motors in a cluster?
You must be a mind reader! I would like to do the same thing with White Lightning and also have the Clusterfire pyrogen. I don’t particularly care for Blue Thunder’s characteristics other than it is easier to ignite.
 

roytyson

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I've done numerous composite clusters with Wildman ignitors tied in parallel, never had a failure. Leave enough wire/leads to reach the top of the rod as they might not ignite all at the same moment.
 

John Taylor

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You must be a mind reader! I would like to do the same thing with White Lightning and also have the Clusterfire pyrogen. I don’t particularly care for Blue Thunder’s characteristics other than it is easier to ignite.
Exactly. The Blue Thunder is VERY easy to light. It usually has a more powerful thrust for heavy rockets but other than that it's boring.
I really love White Lightning and have grown quite fond of sparkies.
Back in the old days a little thermite would light anything quickly.
I've also heard of painting a little pyrogen on the forward grain slot which is not easely done with single use or DMS motors.
I also know about putting a small sliver of Blue Thunder propellent at the head of the forward grain where the igniter head rests.
These methods are increasingly difficult the smaller the motor.
I want to hear from the experienced fliers. Thank you all!
 
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Easy way to light a reloadable G64.(white lightning) Get a C black powder motor, remove cardboard casing. You now have a slug of compressed BP(past the delay section which is a slightly different colour). Cut a small slice off end. Stuff into slot in propellant top.. Use any igniter you want( preferably a first fire) The BP will light immediately and ignite the rest almost instantaneously. Haven't had a chuf,chuf on the pad since I moved to this method. You could also use a slice of blue thunder, but that would cost you a composite reload.
Norm
 
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John Taylor

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Easy way to light a reloadable G64.(white lightning) Get a C black powder motor, remove cardboard casing. You now have a slug of compressed BP(past the delay section which is a slightly different colour). Cut a small slice off end. Stuff into slot in propellant top.. Use any igniter you want( preferably a first fire) The BP will light immediately and ignite the rest almost instantaneously. Haven't had a chuf,chuf on the pad since I moved to this method.
Norm
Thank you
 

heada

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I've clustered composites before with those starters and pyrogen combo. Clustering similar propellant types is a non-issue. 7x G79W is just as easy as 7x F42T motors. All come up to presdure about the same time. Where to watch things is mixing propellant types. I've had the best luck cleaning any oxidation off the propellant. My favorite cluster combo so far has been 6x F42T & 1x H180W. All firing at the same time but since the blues start easier, the white H comes up to pressure about 50 feet off the ground.
 

cerving

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Aerotech changed their igniters a few years ago, the ones with the skinny orange/yellow wires aren't nearly as good as the older ones with the yellow wires. I'd only use one for starting a single motor. I second the recommendation for Wildman igniters, Quickburst igniters are pretty darn good too.
 

StreuB1

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I use a sliver of blue thunder propellant taped to electric matches for clusters. It doesn't take much, a little dab'll do ya.

For my 1x Metalstorm + 6x Dark Matter cluster I flew at Mini MWP, I used chinese ematches and more healthy slivers of BT propellant. The throats of the motors were a lot larger so I used a larger sliver. About 3/32" x 3/8" for the 29mm out boards and 1/8" x 3/4" for the 38mm central J.
 

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I've only done one composite cluster, but I've been told that taping or otherwise fastening motor starters to the rocket in some fashion increases reliability significantly. If the head of the starter stays with the motor it's more likely that it will ignite the propellant properly. Someone please chime in and tell me I'm full of old bootlaces and sardine juice. :)

Best -- Terry
 

fyrwrxz

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Mmmm, tasty! But you are not full of that! I've taped the leads to the rail up high to prevent the weight from dragging them off on first movement. You are correct in securing the igniters to the motor for the same reason. I've seen a few light within inches of the last bit of rail, but they all came up to pressure for stable flights.
 

jimzcatz

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Pyrodex pellets from Walmart and any ematch, Thermite. Ematch and Thermalite. Good luck.
 

rfjustin

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CTI reloads with starter pellet makes it very easy to do a cluster.
Pyrodex pellets from Walmart and any ematch, Thermite. Ematch and Thermalite. Good luck.

Agreed with the use of Pyrodex pellets. Really like augmenting AT 54mm 4 and 6 grain loads with one attached to the delay face. :)
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jimzcatz

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I still have a roll left from the old days but honestly pyrodex pellets are so much easier and reliable. I tape it to an ematch and stick
 

Dugway

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Use the appropriate MJG ematches and a cluster box. You'll be very happy with the results.
 

heada

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What adhesive?
I use just a drop of med CA on the delay grain and place the pellet on that. Seconds later its bonded. CA is off-set to one side so the delay grain can still burn like normal. Also taped it to a 1/8" dowel but I like tacking it to the delay grain better. I've lucked out on some 54mm motors where the grain core was the same width as the pyrodex pellet so it just sits in the forward end of the grain, no tape or glue needed.
 

aerostadt

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The small slot and nozzle on 24 mm motors does not leave much room for putting in extras, although it might be possible. I will probably re-visit the 24 mm composite clusters again sometime.
 

jimzcatz

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Most ematches alone will not light composites
You might get lucky with a blue thunder load
 

Dugway

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Just go to the MJG website and look at Products->Rocketry. They have a variety of "Starters" for both BP and composite. I've never had one not light the motor when paired with a cluster box.
 

jimzcatz

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It's an ematch. You don't need a cluster box. Not gonna hurt but unnecessary. You can light a handful of ematches with a AA battery.
 
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