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Navajo

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Hi Guys,

A quick question....Can you mix up motors when joining two together as a multi stage unit.

Specifically do you think I could use the following combo; An Estes C6-0 for the booster and an Aerotech D21 for the sustainer.

Would this work or will It in end up on disaster?

Thanks
 

powderburner

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You could use an AT upper stage motor, but you will have to use on-board electronics (and power supply) to ignite the motor.

AT motors cannot be 'stacked-n-staged' like the Estes-style BP motors. AT motors burn a composite propellant and can not be ignited by the blow-through from the front end of a BP booster motor.
 

Navajo

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Thanks Powderburner,

You have answered my question. I am getting hold of three D21's shortly, and will not consider using these in any multi stage. Thanks for the insight as to how they work.

Is there any special launch ground support required for sending up an AT as a single stage? I have only ever used Estes and quest black powder motors, and this is the first time I have ever tried something different. ( I would love to see more smoke and hear more noise..!) I have been assured that AT's are the way to go for those "special" launches

Thanks

Navajo:)
 

powderburner

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I certainly ain't no expert at composite motors, having only launched a few.

I can tell you this much: getting those things to go is (IMHO) a cosmic-sized pain in the a**

You need to position the igniter carefully near the top of the grain because the burn characteristics of composite propellants requires a little internal chamber pressure buildup before the motor really starts cooking. Composite motors need to be initiated at the top in order to work properly.
The igniters have quirks of their own----the on-field name for CopperHeads is 'Crapper Heads' (take a wild guess why). I recommend you have a few extra igniters for your first efforts at composite motors.
The igniter leads appear to be a single metallic ribbon, and unless you know what this is, it looks a bit confusing. There is a foil face on one side separated by an insulator from the opposite foil face. You make your ignition hook-up by putting a small piece of tape on one side of the cpprhd and attaching one clip. Next to that, put another small piece of tape on the OTHER side of the ribbon, and attach the second clip there. Then cross your fingers, pray to the God of your choice, spit in the wind, and hope.

Good luck!
 

Navajo

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Hmmmmm.....

I have heard that these Copperheads are pretty crappy....from what i have heard more frustration than joy. I can see I will spend a lot of time scratching my head and cursing. I will get a few extra igniters just in case.

Will a standard estes electron beam controller fire these AT's? or will I need a 12v source to juice it up?

I think I am starting to realise why BP is so popular. I must admit that I have always had ignition on Estes and Quest BP's.

Thanks PowderBurner.

By the way My handle is my favourite aircraft from Piper "who else"

Navajo
 

powderburner

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You are definitely going to want a good 12V system. I would recommend you find one with a battery and relay at the pad (for max power to those igniters) and a remote control panel. There were some threads here on TRF a month or two ago with some good ideas for schematics (sorry but I don't have the links handy, try doing a search using 'relay' or 'ignition').

Where are all you TRF high-power guys with all the knowledge and experience? What do you recommend to make this guy's first composite motor a success?
 

powderburner

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Originally posted by powderburner
The igniter leads appear to be a single metallic ribbon, and unless you know what this is, it looks a bit confusing. There is a foil face on one side separated by an insulator from the opposite foil face.
Your ignition clips need to be the kind WITHOUT serrated jaws. Otherwise, you will clip straight through the ribbon and short straight through both sides, without juicing the tip of the igniter.
 

MarkABrown

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Originally posted by powderburner
Where are all you TRF high-power guys with all the knowledge and experience? What do you recommend to make this guy's first composite motor a success?
Powder, you were doing such a fine job, nobody felt the need to say anything more! ;) :cool: :kill:
 

solrules

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Another option: Thermalite. Im pretty sure it would fit in the nozzle of a D21 (not positive!). They are much more reliable than "Crapper-Heads"; IIRC require less launch voltage (not sure...); and free at my launch (once you sign up to launch for the day, you can get a stick of thermalite for free and wire is sitting on the table). I use these quite a bit, and have not had a failure yet. The only thing I would look out for is if the thermalite is small enough to fit inside the nozzle.

Oh, for thoes of you who dont know what thermalite is: It is like string (IIFC, green) that has a high gauge wire wrapped around it. If you take two seperate wires and wrap them around the thermalite string (but not touching eachoter) and connect the other end to a ignition system, you have one cool igniter.
 

marvSRG

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I'm not going to say very much as everyone has answered all the questions quite well, but just for some imput...I've dealt with crapperheads for a while and I know every way to make them work (the best way being throwing them in the trash and buying some QuickBursts or Fire in the Holes :D). I have however discovered in personal flying (i.e. non club launches), my own personal ignition system can light crappers with as little as 9v. What is my personal launch system? A 15-20ft. double lead wire with microclips on one end and separated and stripped wires on the other....just keep them away from the battery during hookup and then for launch just touch them to each terminal of the battery (usually a 9v or 12v) and a beautiful launch follows...or ignition anyways ;). I always test designs in my personal flying so nobody gets put in danger at the field. Flying Lampshade + G40W= great test flight. Flying Lampshade + F20W= crash that only I and my friend needed to be around. Anyways, back to copper...er..crapperheads. As the other guys said, be careful during hookup and do it correctly, handle them with care (I know it hurts but you gotta do it if ya want 'em to work), and with a 9v+ launch system you should be good. Just expect a second or two for ignition on 9v systems. That's my very long and strung out (as usual) 2 cents. Good luck!
 

RocketboyG80

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Just like to add something about those copperheads. I actually never used one with the interloc clip or the tape on each side method. I always use the method where you hold it over a flame to melt the glue between the two copper strips. Then you just peel it back about one inch and you can hook it up like a regular igniter, even with toothèd clips. Although, I only use copperheads with Bluethunder motor non-cluster flights to ensure that they actually work. I wouldn't use them at all save for the fact that they are practically free as opposed to regular $1 igniters. I prefer to use Quickburst Twiggys or Magnelites.
 

Navajo

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Thanks to all of you for your help and information....In particular powderburner, Marv and Rocketboy.

If I can impose for one more stupid question...do you still stick the igniter up the nozzle and plug it? Or is there something else involved?

navajo
 

powderburner

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For BP motors, you still do it the same old way. Check the igniter visually to see if it looks intact (teeny wires connected, pyrogen still in place). It is MUCH better if you can use a multi-tester to check for continuity, but be careful about using too much juice or you will set off the igniter while you are testing it! Insert the tip of the igniter through the nozzle so the tip is in contact with the BP grain. Secure in place with a plastic plug (comes with the Estes motors, but I don't like them) or a wad of tissue.

For composite motors, the igniter head needs to be in contact with the grain at the forward end of the motor. I have done this by gently sliding the igniter into place, pouring in a few grains of ignition 'enhancer,' then pushing in a wad of tissue VERY gently tamped in place. I have been told by lots of people that I don't need to do the extra stuff, and even that I shouldn't, but I can't get reliable ignition without a little help. Anyway, you secure the igniter leads in place with a little cap or plug (depends on what is provided with the motor).
 

eugenefl

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Originally posted by Navajo
Thanks to all of you for your help and information....In particular powderburner, Marv and Rocketboy.

If I can impose for one more stupid question...do you still stick the igniter up the nozzle and plug it? Or is there something else involved?

navajo
This is a personal opinion, but I would not recommend plugging the nozzle end of the Aerotech motor for one reason and one reason alone. As that igniter starts to burn it builds up pressure of its own. I have experienced far too often that the pressure built up inside the motor "spits" or "pops" the igniter out before it actually ignites the motor. Feel free to tape the end of the nozzle to hold the igniter in place, but be sure and poke a hole in the tape so that the motor can "vent" minimal pressure before it fully ignites.

Enjoy! :)
 

Navajo

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Thanks eugenefl,

I'll take that good tip on board..!
 
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