Bus bars

[dragon_rider10]

Considering parallel cluster with 3 engines. I've seen references to using a bus bar to wire the igniters in parallel. I've never seen it done in person. Would any conductive wire work or is there a particular best practice to consider?

Anyone have photos of such a setup?

john

[Micromeister]

Bus Bars are not a very reliably method of wiring bp clustered motors. Attached is a quicky reference sketch i've had very nearly perfect success since I started using it along with a relay ignition system some 30 years ago.
Hope this helps a little.

[dragon_rider10]

The polarity indications have always confused me. Is there a specific (-) or (+) lead on an igniter?

[The EGE]

The polarity indications have always confused me. Is there a specific (-) or (+) lead on an igniter?

As far as I know there are no polarized igniters. You just have to arbitrarily designate one lead (+) and the other (-) so that current flows across it. On all those clusters, you could switch the (+) and (-), so long as you switched so all ignters still get electricity.

[GregGleason]

Ohhh, it has been a long day.

When I saw the title for this thread, I had a vision of yellow school buses coming to a stop at Joe's Lounge.

Well, ...

... at least my buses were in "recovery".

Greg

[dragon_rider10]

Ohhh, it has been a long day.

When I saw the title for this thread, I had a vision of yellow school buses coming to a stop at Joe's Lounge.

Well, ...

... at least my buses were in "recovery".

Greg

[jsdemar]

Bus bars? I don't see any problem with the idea as long as nobody drinks and drives.

There's no polarity to an igniter. The "+" and "-" indicators on the diagrams are just to make sure each igniter is in parallel with the others. It wouldn't be good to have both ends of one igniter hooked up to "+", for example.

-jsd

[BobH48]

What I always use is extentions on the igniters.

After putting the igniters in the motors, I check continuity on each separately and then twist all the red wires together and all the blue wires together.

[BigRiJoe]

For those of us who are electrical challenged could you tell us the wire type, igniter attachment method and a good place to get the parts?

[Rex R]

well any decent hook-up wire (24ga) should work well, can't tell from the pic if they are soldered... radio shack carries hook-up wire

[MarkII]

I haven't done all that much clustering, but I have had 100% success using clip whips that have a hard connection to the ignition system. With the twisted lead method, I am 1 for 2.

As an aside, I have always read that wiring igniters in parallel was the way to go, and that one should avoid wiring them in series. Yet Boris Katan has talked about wiring igniters in series in some of the circuits in his massively-clustered rockets. I think he said that it was the only way to get enough juice to the dozens of igniters that he uses in his flights. I haven't been able to figure out how he gets away with using that type of circuit, but he seems to be successful with it.

[gpoehlein]

I've only just gotten started with clustering (I built a clone of the Estes Ranger to try it out) and these things are a lot of fun! I've been using the Quest Q2G2 igniters for my clusters - the longer insulated wires are perfect for clustering without clip whips, bus bars or anything else - just twist one the ends of the leads together in parallel and you're good to go. Plus, they take so little current to fire (they are NOT Estes controller friendly) that three of them light with no trouble at all! I can't wait to try my newest build - the Tube Daddy (tube finned Big Daddy with three 24mm motor mounts )

[judo]

I solder extentions onto my ignitors as well. I've got a BUNCH of scrap wire, CAT 5, I think. I cut it to about a 5"-6" in length and pull the little wires out of the sheath. Strip the ends, seperate the white/chaser from the ones that aren't white/chaser (if you read anything into that, please don't post it) and solder one to each ignitor.

And just for my own piece of mind, I wrap a bit of electrical tape around the connection.

Works for me.

I have three cluster rockets: TLP ALARM (2x24), Fat Boy (3x18), and PS Patriot (4x24).

[MarkII]

I may try that; I have a bit of Cat V stashed away. I haven't launched a cluster since last year, before I ever got any Q2G2s (and my Quest controller). I've got Cobra and Ranger clones (Greg, what did you end up doing to strengthen the fins?) that I really should get back to and finish so that I can give those igniters a try. Using my clip whips requires using my launch controller, which isn't possible at club launches.

[gpoehlein]

I may try that; I have a bit of Cat V stashed away. I haven't launched a cluster since last year, before I ever got any Q2G2s (and my Quest controller). I've got a Ranger that I really should get back to and finish up (Greg, what did you end up doing to strengthen the fins?) so that I can give those igniters a try. Using my clip whips requires using my launch controller, which isn't possible at club launches.

I just sanded and sealed them. I built the Ranger from a Big Bertha. I cut the body tube where the payload compartment was supposed to be and turned a CT-60 coupler into a plug by cutting two disks of 1/2" foam core and gluing one into each end of the coupler. I used the nose cone as is (I know - the Ranger had a balsa nose cone, but I didn't feel like the hassle and it is good enough for me ) as well as the fins. I then cut three motor tubes from BT-20 and glued them together as in the Ranger instructions, then filled the gaps with glue soaked tissue. Worked fine for me. I also did not try to install any motor clips - I've flown it a half dozen times so far and haven't kicked a motor yet. It flies great on Quest A6-4s and B6-4s - they are nice and smoky during flight and it's a really stable model. Haven't wanted to risk it on C6s yet.

[Handeman]

As an aside, I have always read that wiring igniters in parallel was the way to go, and that one should avoid wiring them in series. Yet Boris Katan has talked about wiring igniters in series in some of the circuits in his massively-clustered rockets. I think he said that it was the only way to get enough juice to the dozens of igniters that he uses in his flights. I haven't been able to figure out how he gets away with using that type of circuit, but he seems to be successful with it.

There are several threads, either here or in the archive, or RP?, about how Boris did the parallel/series connections. He did a lot of ground testing of igniters and knew exactly how they worked under the conditions he used. I do remember one thread where he explains exactly how and why he uses the series connection and why they work.

[BobH48]

For those of us who are electrical challenged could you tell us the wire type, igniter attachment method and a good place to get the parts?

I use a wire wrap tool and 30 gauge wrapping wire from Radio Shack.

Wrapping wire and tool

the leads are not soldered

[MarkII]

There are several threads, either here or in the archive, or RP?, about how Boris did the parallel/series connections. He did a lot of ground testing of igniters and knew exactly how they worked under the conditions he used. I do remember one thread where he explains exactly how and why he uses the series connection and why they work.

Yes, and I read those threads back when they were made; I also attended a workshop presented by Boris at this year's NARCON and read his article in Sport Rocketry when it appeared awhile back. Obviously he knows what he is doing; I wasn't trying to imply otherwise. (The proof of that is in his many successful launches.) Despite all of the explanation, I still don't fully understand what he does and how he achieves success. (Some of the theory, not to mention the technique, is well beyond the kiddie end of the pool where I dip my toes.) I do know that one part is that he uses high quality igniters that he dips himself, and also that he does beaucoups testing beforehand, as you pointed out. He also takes great care in designing the elaborate cobweb of wiring for the igniter connections.

[MarkII]

From this site:



Trying to trace all of the wiring in that picture makes my head hurt... There are more motors loaded for that one flight than I usually burn in a year.

[Micromeister]

Mark:
I think the easiest way to look at clustering is its all about balancing the load to get each and every igniter enough current at the same instant.
3 or 30 you still need both sides of the battery connected to each igniter and delivering enough juice (current NOT VOLTS) to heat the igniter. While the + and - signs are arbitrary as far as the individual igniter goes they become VERY important when considering many igniters. As someone already posted getting to many of one or the other on the same igniter means it will not ignite period, regardless of how many amps your pushing.

Personally the largest cluster i've built and successfully flown has been a 12 motor bp combination. Generally I'm happy staying within the 125g LMR propellant limit.

Instant ignition is also about the time it takes to bring all igniters up to burn temp. the more instantaniously the better as long as we don't pop those tiny 38gauge bridge wires so quickly they don't have time or heat to bring the pyrogen or propellant up to ignition temp.
You are exactly correct tho...Boris method works well for him, and he is STILL experimenting with additional ways to make his system work even better. As I've said for years Clustering is not just a Science it's also an ART. We really have to experience and become immersed in the practice before we really begin to appreciate everything that's going on inside at the moment of ignition I know I'm still learning everytime I add or subtract something to a clustering preperation procedure.

[WillyK]

Folks,

There are probably many acceptable ways to wire for clusters. The largest to date for me has been 4x BP. But, I have more plans on the horizon

Never used clip whips... just didn't get into the idea. If you're not into dipping your own igniters, I've used successfully the new Quest Q2G2 igniters (both leads are same color, mark one lead with a black sharpie). Prior to that I've also added 30 gauge wire wrap to the leads of an Estes igniter. Didn't wire wrap (although seems like a great idea), but did solder. A bit of work, but if you sit down some evening and do up a bunch, you can make up a bunch to last awhile. It gives you the flexibility to choose just how much lead wire you want (I used to do about 6") and by color-coding the different leads it was easy when it came to hooking multiple igniters up in parallel.

I've also had success with the hand-dipped igniters that Boris uses. This is the Rocketflite,
http://www.rocketflite.com/
(Greg Dyben's) Magfire "low-amp" pyrogen. For the smaller nozzle motors (RMS 24mm FJ's) instead of using Rocketflite's 26 gauge MF-12 wires, I've used FireStar's
http://www.craftershome.net/FireStar/
(Scott Dyben... yes they are brothers) 30 gauge low-amp FS-12-LA igniter wire for dipping with the Rocketflite product.

Not affiliated with either of these companies, just a happy customer.

So, many options out there.

... Bill

[JRThro]

I can't comment on bus bars, since I haven't used them.

But I have successfully clustered 2, 3, and 4 BP motors using Estes igniters with the leads twisted together, without using any extensions of the leads. It's kind of a pain, especially with 4 motors, but it's worked for me so far.

[Solomoriah]

I've twisted leads for up to three engines with good results so far... but for my 4x18 Big Daddy I think I'm going to order some Q2-G2's. My launch control system is all LED so they should work fine.

[MarkII]

I have made several launches of my 3-motor Micromaxx cluster saucer (a modified version of Art Applewhite's free MMX original saucer plan) using a standard clip whip and QMX igniters that were stripped of their plastic housings and supported in the nozzles by toothpicks. The motors are bunched together, Estes Ranger-style, instead of being spread apart like they are in the Diminutive Deuce. So, as you can imagine, space is tight. Also, the toothpick supports are very much on the rickety side. Finally, the leads on the QMX igniters are quite short. These igniters, like the current Micromaxx ones, have no pyrogen, just a bare length of nichrome bridge wire between the leads. It is really tricky to get everything hooked up without touching or falling off, especially when you are using a Quest Silo launch pad that is sitting on the ground. Still, it can be done. I have a perfect record with that saucer. I use my AT Interlock controller with a 12 volt power source to fire them.

[Micromeister]

I have made several launches of my 3-motor Micromaxx cluster saucer (a modified version of Art Applewhite's free MMX original saucer plan) using a standard clip whip and QMX igniters that were stripped of their plastic housings and supported in the nozzles by toothpicks. The motors are bunched together, Estes Ranger-style, instead of being spread apart like they are in the Diminutive Deuce. So, as you can imagine, space is tight. Also, the toothpick supports are very much on the rickety side. Finally, the leads on the QMX igniters are quite short. These igniters, like the current Micromaxx ones, have no pyrogen, just a bare length of nichrome bridge wire between the leads. It is really tricky to get everything hooked up without touching or falling off, especially when you are using a Quest Silo launch pad that is sitting on the ground. Still, it can be done. I have a perfect record with that saucer. I use my AT Interlock controller with a 12 volt power source to fire them.

To be perfectly honest: 2 & 3 motor clusters should work fine with just about any attachment method as long as your using a 12V battery and short lead lines.....most of the time. A bad igniter, sloppy igniter installation or hap-hazard twisting can cause less then the desired results. and for the casual 2,3, & sometimes 4 motor cluster flyer that'll work out fine.

But please understand a clipwhip is nothing more then an extension of the existing system to which it is connected. It is also adding another potential problem area in the connection/attachment points. If well made, with good materials a clipwhip should work just fine on small 2, 3 and most 4 motor clusters.
It's in the higher number of motor clusters, that Relay systems with direct leads, larger gauge wire connection and so on become so important. Preperation time and attention to detail are the most critical part to 3 & 4 motor clustering success that is: ensuring all igniters are good and in contact with the propellant, Contact clips and connections are clean and Tight, and the battery can supply the necessary 2amps pre igniter.

I started using Relays on all clusteres more the 30 years ago when I only got 3 of 4 motor to light on my brand new 1/70th Scale Saturn 1B. I wanted to be able to give myself and my clustered models the very best chance of success on every flight. That Saturn-1B and most of my other clusters are still flying. My cluster motor success rate is not perfect.. some intentional most not, I've Logged 13 unlit motors in all those thousands of clustered flights over the years.. but that's still a very high success rate. The more one practices a particular thing, studies the process involved and works out a procedure that works for their particular flying style, that individual will have the most fun with the ART of Clustering.

Some years back I wrote an Article "Clustering BP motors" that's published as a Tech-Tip in the Library at www.narhams.org Tip-006 has been updated periodically and is available for anyone to download or just read at their leasure if they are interested clustering BP motors. While it's not the only answer it's certainly been extremely successful for many who have used it's contents.