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How to Light 3 Motors

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AidanDelli

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So after some research, I have not found whether or not a single Estes launch controller is capable of lighting 3 engines at the same time. I have the engines in a triangle cluster very close together so the wires on the bottom of the engines can all touch. My plan is to just connect 1 wire from each engine to one of the clamp things on the controller while also making sure none of them touch any others. Will the controller be able to light all of them a once? I really don't know what I am doing and would be open to any other suggestions you may have to launch it. Thanks!

I haven't built this rocket yet but am designing it in OR and want to make sure I can actually manage to get it off the launchpad first.
 

Bat-mite

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AidanDelli

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Thanks for the fast responses everyone! I do have 3 igniters laying around and will try those first, but if they don't work I will definitely buy a clip whip. I've never heard of them before but they seem perfect for this type of use!
 

CoyoteNumber2

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Thanks for the fast responses everyone! I do have 3 igniters laying around and will try those first, but if they don't work I will definitely buy a clip whip. I've never heard of them before but they seem perfect for this type of use!
If your controller doesn't have the juice to light three igniters, a clip whip will not help you. A clip whip just makes it easier to hook them up.
 

AidanDelli

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That makes sense. Would you recommend going up to the 12V controller previously mentioned if that was the case?
 

cerving

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I'd pretty much guarantee that the Estes launch controller with the four AA batteries ain't gonna light 3 igniters, unless you can find some AA size Ni-Cads to replace the alkaline batteries with. Get a 12V system, they work great with gel cels or small motorcycle batteries. You should be able to make a clip whip pretty easily from stuff you can get at your local hardware store.
 

dhbarr

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I'd pretty much guarantee that the Estes launch controller with the four AA batteries ain't gonna light 3 igniters, unless you can find some AA size Ni-Cads to replace the alkaline batteries with. Get a 12V system, they work great with gel cels or small motorcycle batteries. You should be able to make a clip whip pretty easily from stuff you can get at your local hardware store.
I run 4x LiFeS2 AA in my E controller, and have had no problem with 4x FirstFire Jr touching off 18mm APCP.

It's doable, but I'd recommend a solid 12v setup.
 

BABAR

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I run 4x LiFeS2 AA in my E controller, and have had no problem with 4x FirstFire Jr touching off 18mm APCP.

It's doable, but I'd recommend a solid 12v setup.
How do FirstFires compare with The new Estes igniters.......er,,.... "starters"? I do a number of black powder cluster, far from an expert, most I have done is 4, usually 2 or 3. I wouldn't trust standard Estes controller with any cluster unless I had the Quest Q2G2 igniters, which I believe are out of production and awful hard to find.

even if a test fire of three standard Estes igniters worked, I still would not trust it to work in practice.

Go twelve volt.
 

SDramstad

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Zeus-cat

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You want them in parallel, not serial.
SDramstad is correct. If you put them in series you can lose continuity as soon as one igniter lights as it may burn through the bridge wire. If they are in parallel the continuity is maintained for the other igniters even after one lights and burns through.
 

Steve Shannon

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SDramstad is correct. If you put them in series you can lose continuity as soon as one igniter lights as it may burn through the bridge wire. If they are in parallel the continuity is maintained for the other igniters even after one lights and burns through.
Not always. Boris Katan is the master of clusters. Here are a couple of links to his website explaining his techniques.

https://bpasa.com/Cluster-box.htm

https://bpasa.com/Rocketflite.htm


Steve Shannon
 
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The_Lone_Beagle

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You want them in parallel, not serial.
Think about it.

The clip whip puts all the igniters in parallel. Problem solved.

You can, however, ignite igniters serially, provided you have the correct igniters.

I don't have a proper drawing program, but if you want to ignite 3 igniters with just 2 leads, you will have to put at least 2 of the 3 in series. Not sure which igniters the OP has, but here is a video explaining:

[video=youtube;4ZqpFCTS4P8]https://www.youtube.com/watch?v=4ZqpFCTS4P8[/video]
 
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Steven

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I use the Mighty D myself by BMS. Uses eight (8) D cells for power plus a nine (9) volt for the continuity light. Nice setup which could light a forest fire.
 

The_Lone_Beagle

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I use the Mighty D myself by BMS. Uses eight (8) D cells for power plus a nine (9) volt for the continuity light. Nice setup which could light a forest fire.
Didn't want to clog my previous posts with too much info, but for clusters you really want to use 12v.

And once you use 12v, you likely ain't ever going to go back to any other wimpy launchers. I remember the old days of mashing down on the launch button and holding it...the first time I hooked up a controller to a car battery and then pressed the button, the rocket pretty much launched immediately. No button mashing/holding required!
 

Steven

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Didn't want to clog my previous posts with too much info, but for clusters you really want to use 12v.

And once you use 12v, you likely ain't ever going to go back to any other wimpy launchers. I remember the old days of mashing down on the launch button and holding it...the first time I hooked up a controller to a car battery and then pressed the button, the rocket pretty much launched immediately. No button mashing/holding required!
There's no time lapse with this setup either, the rocket is gone. It's the equivalent of 12 volts: 1.5v x 8v = 12v.
 

FredA

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You light things using heat....the bridge wire heats the pyrogen to it's ignition temperature.
Heat is proportional to I*I*R ... note, no mention of voltage.
CURRENT lights things....

Wiring in parallel demands higher current.
Parallel wiring will only distribute the current equally if the individual resistances are equal.
Without equal current distribution, the timing of ignition will vary.

Wiring in series guarantees the exact same current flows through each igniter.
However if the resistances are not equal, the heat generated will not be equal....but since current is squared, equal current is more important than equal resistance.
The problem with series wiring is that if one igniters opens, current stops flowing.
But usually one of two things keeps the current flowing:
1 - the bridge wire does not open - this is my typical experience with Estes style igniters, but that's admittedly dated experience.
2 - A plasma ball surrounds the igniter and if it opens, for a brief moment, the plasma ball will conduct the current.

Conventional wisdom is to wire in series....that's when more voltage helps to push more current though the igniters.
Using Ohm's law: I=V/R

When I'm doing airstarts, I like to have a single battery on it's own switched circuit for each motor. I consider that the most reliable method. I make my own airstart firing circuit.
 
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Steve Shannon

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You light things using heat....the bridge wire heats the pyrogen to it's ignition temperature.
Heat is proportional to I*I*R ... note, no mention of voltage.
CURRENT lights things....

Wiring in parallel demands higher current.
Parallel wiring will only distribute the current equally if the individual resistances are equal.
Without equal current distribution, the timing of ignition will vary.

Wiring in series guarantees the exact same current flows through each igniter.
However if the resistances are not equal, the heat generated will not be equal....but since current is squared, equal current is more important than equal resistance.
The problem with series wiring is that if one igniters opens, current stops flowing.
But usually one of two things keeps the current flowing:
1 - the bridge wire does not open - this is my typical experience with Estes style igniters, but that's admittedly dated experience.
2 - A plasma ball surrounds the igniter and if it opens, for a brief moment, the plasma ball will conduct the current.

Conventional wisdom is to wire in series....that's when more voltage helps to push more current though the igniters.
Using Ohm's law: I=V/R

When I'm doing airstarts, I like to have a single battery on it's own switched circuit for each motor. I consider that the most reliable method. I make my own airstart firing circuit.
Very good explanation!
 

FredA

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Very good explanation!

Thanks Steve.

Why is this in the Watering Hole???? I would have thought it should be in Ground Support.
 

The_Lone_Beagle

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You light things using heat....the bridge wire heats the pyrogen to it's ignition temperature.
Heat is proportional to I*I*R ... note, no mention of voltage.
CURRENT lights things....

Wiring in parallel demands higher current.
Parallel wiring will only distribute the current equally if the individual resistances are equal.
<snip>
Conventional wisdom is to wire in series....that's when more voltage helps to push more current though the igniters.
Using Ohm's law: I=V/R
Wait a minute...if heat is proportional to I^2, and I = V/R, wouldn't heat then be proportional to V^2?

Trying to remember my high school physics*...current is the rate at which voltage flows. If you double the voltage (from 6v to 12v), you increase the current & then you get 4x the heat for a constant resistance wire, since heat/power = I^*R.

*I couldn't remember my HS or even college physics, I got this out of the Handbook of Model Rocketry, p. 88!
 

FredA

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Yes, current and voltage are related following Ohms law.
Just know that it is the current that is doing the heating.
And understand that the matching the current though multiple igniters is why you wire in series instead of parallel.
 

SDramstad

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You light things using heat....the bridge wire heats the pyrogen to it's ignition temperature.
Heat is proportional to I*I*R ... note, no mention of voltage.
CURRENT lights things....

Wiring in parallel demands higher current.
Parallel wiring will only distribute the current equally if the individual resistances are equal.
Without equal current distribution, the timing of ignition will vary.

Wiring in series guarantees the exact same current flows through each igniter.
However if the resistances are not equal, the heat generated will not be equal....but since current is squared, equal current is more important than equal resistance.
The problem with series wiring is that if one igniters opens, current stops flowing.
But usually one of two things keeps the current flowing:
1 - the bridge wire does not open - this is my typical experience with Estes style igniters, but that's admittedly dated experience.
2 - A plasma ball surrounds the igniter and if it opens, for a brief moment, the plasma ball will conduct the current.

Conventional wisdom is to wire in series....that's when more voltage helps to push more current though the igniters.
Using Ohm's law: I=V/R

When I'm doing airstarts, I like to have a single battery on it's own switched circuit for each motor. I consider that the most reliable method. I make my own airstart firing circuit.
Yes current lights igniters, by putting them in series you triple the resistance therefore you lower the current to a third of what you would get if you put them in parallel. Let's say each igniter is 2 ohms with a 12 volt system. If you wire in series you end up with 6 ohms resistance, 2 amps through each igniter. Wire in parallel and you get 6 amps through each igniter, 18 total. Wiring in parallel gives you more current through each igniter then series every time.
 

Steve Shannon

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Yes current lights igniters, by putting them in series you triple the resistance therefore you lower the current to a third of what you would get if you put them in parallel. Let's say each igniter is 2 ohms with a 12 volt system. If you wire in series you end up with 6 ohms resistance, 2 amps through each igniter. Wire in parallel and you get 6 amps through each igniter, 18 total. Wiring in parallel gives you more current through each igniter then series every time.
That's correct, but you also have to consider the maximum current your launch controller can deliver based on the battery internal resistance, size of wires, etc.
The right way to do it is not to simply choose parallel or serial, but work backwards from the necessary current for all of igniters or electric matches and figure out what combination of series and parallel connections can serve all of the loads.
For small cluster, 3 or 4 motors using electric matches,it could go either way.


Steve Shannon
 

The_Lone_Beagle

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Yes current lights igniters, by putting them in series you triple the resistance therefore you lower the current to a third of what you would get if you put them in parallel. Let's say each igniter is 2 ohms with a 12 volt system. If you wire in series you end up with 6 ohms resistance, 2 amps through each igniter. Wire in parallel and you get 6 amps through each igniter, 18 total. Wiring in parallel gives you more current through each igniter then series every time.
Thanks for that, that's a clear explanation.
 
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