Cluster Ignitor Confirmation

[DirkTheDaring]

I had a very bad cluster day a couple of days ago. I'd like a launch controller that can confirm that all the ignitors are connected.

NOTE: I'd like this thread to focus on confirming that all connectors are electrically connected to the controller, rather than all the many other factors involved in successful clustering. I'm aware that there are many other threads about clustering, but it's time consuming to work my way through them all.

I'm not an electrical engineer, and I don't play one on TV. According to my trusty multimeter the resistance of an Estes ignitor is just too low to be a reliable measure. (In series more ignitors would have a higher resistance, in parallel, lower.) In series, you'd be able to tell if all were connected, but generally parallel is the recommended approach.

Other than separate leads for each ignitor, does anyone have any ideas for a controller that can confirm that 2, 3, or 4 ignitors are firmly connected?

PS I built my own cluster whip and I use toothed alligator clips rather than flat (a personal preference), but it seems even when I try to be super careful I still mess up often enough to be an issue.

I'm open to any ideas, thank you.

 

[UhClem]

In order for a controller to do what you want you would need a four wire connection to remove the variability introduced by the connecting wires. I have never seen anyone build a launch controller that way.
When I am feeling paranoid about clusters (usually) I pull out a four wire resistance meter with a 2 Ohm range that I built. Cheaper than commercial igniter testers but works just as well. I can easily spot shorts and opens.

Instead of fiddling around with a clip whip I like to prepare Estes igniters with extension wires. I use wire wrap wire and two colors. So when twisting them together I grab all the reds and then all of the blues.

 

[DirkTheDaring]

Thanks, that 2 Ohm range meter is probably just the ticket! I'll take a good look at your web page. And wow, wire wrap wire! I haven't seen that in probably 40 years! I can see using a manual wrapping tool with the wire and the ignitor, what a great idea!

Thanks again!

 

[cerving]

If your club's launch controller has a "drag race" mode, use a separate channel for each igniter. You can check the continuity separately that way, and they'll all fire when you hit the button. Of course, your club may object to tying up four outputs...

 

[maxim]

Hello
Can anyone please help me. I have a cluster with 3 estes engines and estes pro II controller. How do I use it ? Do I need another adopter to fire 3 engines at once or is there a way to twist the wires together? I don't understand how, please help thank you

 

[lakeroadster]

Hello
Can anyone please help me. I have a cluster with 3 estes engines and estes pro II controller. How do I use it ? Do I need another adopter to fire 3 engines at once or is there a way to twist the wires together? I don't understand how, please help thank you

You can use the std Estes ignitors and install them according to the diagram below.

​

__________________________________________________________________________________________________________________________________________________________________

I personally use a clip whip that I made myself, and e-matches. Thus far, knock on wood, , I've had a 100% success rate firing all the motors in the cluster rockets I've designed.

​

I had a very bad cluster day a couple of days ago. I'd like a launch controller that can confirm that all the ignitors are connected.

NOTE: I'd like this thread to focus on confirming that all connectors are electrically connected to the controller, rather than all the many other factors involved in successful clustering. I'm aware that there are many other threads about clustering, but it's time consuming to work my way through them all.

I'm not an electrical engineer, and I don't play one on TV. According to my trusty multimeter the resistance of an Estes ignitor is just too low to be a reliable measure. (In series more ignitors would have a higher resistance, in parallel, lower.) In series, you'd be able to tell if all were connected, but generally parallel is the recommended approach.

Other than separate leads for each ignitor, does anyone have any ideas for a controller that can confirm that 2, 3, or 4 ignitors are firmly connected?

PS I built my own cluster whip and I use toothed alligator clips rather than flat (a personal preference), but it seems even when I try to be super careful I still mess up often enough to be an issue.

I'm open to any ideas, thank you.

Hey Dirk, a few questions:

What type of ignitors are you using?​

Do you do a continuity test on the individual ignitors before firing?​

Do you use a clip whip or are you twisting the ignitors together?​

​

 

[maxim]

You can use the std Estes ignitors and install them according to the diagram below.

View attachment 535712​

I personally use a clip whip that I made myself, and e-matches. Thus far, knock on wood, I've had a 100% success rate firing all the motors in the cluster rockets I've designed.

Thanks so much!! I'll try it out with my kid today. You do recommend getting Clip Whip for 3 ? I'll be able to fire using 9v ?

 

[lakeroadster]

Thanks so much!! I'll try it out with my kid today. You do recommend getting Clip Whip for 3 ? I'll be able to fire using 9v ?

A 9 volt small battery.... to be honest... I don't know.

I use a Pratt Hobbies Go-Box controller, powered by a 12V car battery. I bought it because I knew I would be doing clusters.

 

[maxim]

You can use the std Estes ignitors and install them according to the diagram below.

View attachment 535712​

__________________________________________________________________________________________________________________________________________________________________

I personally use a clip whip that I made myself, and e-matches. Thus far, knock on wood, , I've had a 100% success rate firing all the motors in the cluster rockets I've designed.

View attachment 535714View attachment 535715
View attachment 535716View attachment 535719View attachment 535718View attachment 535717
​

Hey Dirk, a few questions:

What type of ignitors are you using?​

Do you do a continuity test on the individual ignitors before firing?​

Do you use a clip whip or are you twisting the ignitors together?​

​

This looks really cool
I want a whip now lol

 

[lakeroadster]

Well

This looks really cool
I want a whip now lol

Well of course you do... whip it, whip it good. Nothing beats a "Cool Whip".

 

[LithosphereRocketry]

Thanks so much!! I'll try it out with my kid today. You do recommend getting Clip Whip for 3 ? I'll be able to fire using 9v ?

I would absolutely not trust clusters with anything less than a high-current capable 12V battery, either a lead-acid gel cell or a LiPo. I'd especially not trust it with the basic Estes igniters. Google says a typical 9V battery has about 1-2 ohms of internal resistance; this means you lose 1-2 volts of output per amp of current draw, meaning that at about 2A per igniter you're down to 5-7 V for just one, with the picture only getting worse as you add more.

I also really don't like the current snot-looking Estes igniters for clustering -- they just take way too much current to light reliably, and if the tip isn't in perfect contact with the propellant you won't get anything no matter how much juice you give them. If you can find the older black-tipped igniters, those are much better as the black pyrogen stuff lights easier than the powder does, giving you a bit more leeway. Ematches are definitely the way to go, though -- they're much more reliable and only require a few hundred mA of current, although I'd still definitely go for a 12V battery if you can. I highly recommend grabbing a box of MJG Firewires -- they're not super cheap, but you get basically a lifetime supply at once, and they're much more reliable than many of the other options on the market (as well as being ATF certified, unlike most of the no-names.)

 

[DirkTheDaring]

I would absolutely not trust clusters with anything less than a high-current capable 12V battery, either a lead-acid gel cell or a LiPo. I'd especially not trust it with the basic Estes igniters. Google says a typical 9V battery has about 1-2 ohms of internal resistance; this means you lose 1-2 volts of output per amp of current draw, meaning that at about 2A per igniter you're down to 5-7 V for just one, with the picture only getting worse as you add more.

I also really don't like the current snot-looking Estes igniters for clustering -- they just take way too much current to light reliably, and if the tip isn't in perfect contact with the propellant you won't get anything no matter how much juice you give them. If you can find the older black-tipped igniters, those are much better as the black pyrogen stuff lights easier than the powder does, giving you a bit more leeway. Ematches are definitely the way to go, though -- they're much more reliable and only require a few hundred mA of current, although I'd still definitely go for a 12V battery if you can. I highly recommend grabbing a box of MJG Firewires -- they're not super cheap, but you get basically a lifetime supply at once, and they're much more reliable than many of the other options on the market (as well as being ATF certified, unlike most of the no-names.)

I've started using the MJG ematches, but what is the best way to keep them inserted? I've been using the old masking tape method, but I'm wondering if there's a better way. Thanks.

 

[LithosphereRocketry]

I've started using the MJG ematches, but what is the best way to keep them inserted? I've been using the old masking tape method, but I'm wondering if there's a better way. Thanks.

I usually just use masking tape- they make a good amount of flame so they're not super picky.

 

[lakeroadster]

I usually just use masking tape- they make a good amount of flame so they're not super picky.

I use e-matches, for BP clusters and they come with a plastic safety cap. I've found that cutting that little cap with some side cutters makes a nice little retainer when used in conjunction with masking tape.

Back in the day, before Estes supplied the plastic ignitor retainers, we'd wad up some tissue paper to do basically the same thing as I described above.

 

[DirkTheDaring]

I usually just use masking tape- they make a good amount of flame so they're not super picky.

Thanks.

 

[RocketRev]

I use e-matches, for BP clusters and they come with a plastic safety cap. I've found that cutting that little cap with some side cutters makes a nice little retainer when used in conjunction with masking tape.

Back in the day, before Estes supplied the plastic ignitor retainers, we'd wad up some tissue paper to do basically the same thing as I described above.

View attachment 536958View attachment 536957View attachment 536956View attachment 536955

Hey, I have to ask....what is the rocket with the F-79 tail number with its ventral surfaces facing up? I don't recognize it. It looks like something I'd like to build.
Brad "was curious........"

ps: oh dear...sounds like the beginning of a Curious George book.

 

[lakeroadster]

Hey, I have to ask....what is the rocket with the F-79 tail number with its ventral surfaces facing up? I don't recognize it. It looks like something I'd like to build.
Brad "was curious........"

ps: oh dear...sounds like the beginning of a Curious George book.

Link to build thread: Lakeroadster's F-79 Lone Wolf

 

[RocketRev]

Hey, I have to ask....what is the rocket with the F-79 tail number with its ventral surfaces facing up? I don't recognize it. It looks like something I'd like to build.
Brad "was curious........"

ps: oh dear...sounds like the beginning of a Curious George book.

Thanks. It's a good thread

 

[BEC]

I would absolutely not trust clusters with anything less than a high-current capable 12V battery, either a lead-acid gel cell or a LiPo. I'd especially not trust it with the basic Estes igniters. Google says a typical 9V battery has about 1-2 ohms of internal resistance; this means you lose 1-2 volts of output per amp of current draw, meaning that at about 2A per igniter you're down to 5-7 V for just one, with the picture only getting worse as you add more.

The PSII controller that @maxim asked about uses 6 C-cells to get 9V, not one of those little 9V batteries. It also has a built-in two-motor clip whip (well, two clip leads on each igniter lead).

It will easily fire a two-motor cluster using regular Estes igniters. I've not tried three.

I also really don't like the current snot-looking Estes igniters for clustering -- they just take way too much current to light reliably, and if the tip isn't in perfect contact with the propellant you won't get anything no matter how much juice you give them. If you can find the older black-tipped igniters, those are much better as the black pyrogen stuff lights easier than the powder does, giving you a bit more leeway.

The "snot-looking Estes igniters" are not the current ones. The current ones (as in the last couple of years) are grey and work as well as the old ones. They are a touch slower, so it's not good to mix them with the old black ones in a cluster.

Ematches are definitely the way to go, though -- they're much more reliable and only require a few hundred mA of current, although I'd still definitely go for a 12V battery if you can. I highly recommend grabbing a box of MJG Firewires -- they're not super cheap, but you get basically a lifetime supply at once, and they're much more reliable than many of the other options on the market (as well as being ATF certified, unlike most of the no-names.)

The PSII controller would have NO trouble with three of the MJG e-matches.

Of course there is another thread about putting a 3s LiPoly in this controller....for even more capability.

 

[LithosphereRocketry]

The PSII controller that @maxim asked about uses 6 C-cells to get 9V, not one of those little 9V batteries. It also has a built-in two-motor clip whip (well, two clip leads on each igniter lead).

It will easily fire a two-motor cluster using regular Estes igniters. I've not tried three.



The "snot-looking Estes igniters" are not the current ones. The current ones (as in the last couple of years) are grey and work as well as the old ones. They are a touch slower, so it's not good to mix them with the old black ones in a cluster.


The PSII controller would have NO trouble with three of the MJG e-matches.

Of course there is another thread about putting a 3s LiPoly in this controller....for even more capability.

Thank you for the correction on C cells - those would do a much better job on clusters, although I'd still prefer something higher-current.

I haven't bought Estes motors in a little while since I tend to buy in bulk, so I haven't tried the new igniters, so I can't speak to that. I know with the snot igniters I get regular enough ignition failures even on 12V SLA that I wouldn't trust them with clustering in any circumstances, and I've had one cluster ignition failure out of 3 launches even with the "good" black-tip Estes igniters on 12V so even those aren't perfect.

As mentioned, C cells on ematches are probably fine, but why bother? Throwing a 3S LiPo in the PSII controller is definitely the easiest way to go at only a $20 investment - that should have no problem with any reasonable igniter combination and will handle proper HPR igniters as a bonus.