Cluster ignition help needed

[Marc_G]

Hi guys,

I tried my first cluster launch today. It was a Der Big Red Max (green, actually) with a 3x18 mount (I'll post more on my interchangeable mount system in LPR soon), and based on how it flew with a single D5-4 I figured 3 x Estes B6-4 would do nicely.

I used 3 Quest Q2G2 ignitors, with the leads wrapped together (so no whip needed). The ignitors were stuck into the engines and "held there" with the straws that accompany the ignitors.

To launch it, I used a routine Estes launch controller (4xAA batteries), with a modified sequence (hold down fire key, then insert launch key to ignite) since I've read that the continuity current in standard Estes controllers can ignite the Quest ignitors.

Only one engine caught. Got 10 feet up then crashed to the ground. Video coming (uploading to Youtube now). Annoyed me as it broke off a fin and slightly crimpt the BT.

Examination of the ignitors (still attached to the launch leads) showed all three ignitors had fired.

I'm wondering if one of them fired first, caught the engine, moving the rocket and the others got pulled out before they could ignite their engines.

Should I have taped the ignitors on or something?

I have other threads here about handling the current needed for Quest ignitors on the continuity test circuit (bought parts, haven't set up yet), but I was hoping to get away with just the AA batteries by using the low power Quest ignitors.

Any thoughts on successful clustering appreciated!

Will post video when available. It's pretty laughable. Next time I'll have people sit farther back!

Marc

[Marc_G]

OK here's the video:


http://www.youtube.com/watch?v=zKfBTMCO8iE

[JAL3]

My answer when I read the thead title but before I read your post was "Use the Quest Q2G2 ignitors" Then I saw that you had and it surprized me since I have a perfect record with them.

While the estes continuity lamp can indeed set off the Quest igniters because of the amperage it draws, I would suspect you would have better luck with a 12v system. I'd also make sure the igniterss are seated in the nozzles with contact against the propellant.

That's my 2 cents but I am not an expert like some around here are. I like clusters and have had some success with them and that success went to 100% with the Quest igniters but my club launches with a 12 volt system driven by an automotive battery.

Good luck.

[gpoehlein]

I echo what John said. Our club launcher uses an RC rechargeable pack (11.6V I think) and is flashbulb safe. What launch controller were you using. If you have one or are willing to buy one, I would recommend using the Quest launcher. The do sell a 12V adapter, but you can go to your local Radio Shack and get a pack of 9V clips and some wire and make an adapter yourself. For power, either get a 12V deep cycle gel cell (expensive) or pick up a rechargeable jump pack for about $30 at a Harbor Freight or Rural King type store. The quest launch controller will handle 12V and is designed to work with the Q2G2 igniters.

Only other thing I can suggest is to double check your wiring and make sure the igniters are all wired together in parallel and not series. With six wires coming out of the bottom of a rocket, it is easy to cross some leads and miswire it.

[bguffer]

Stake the wire that goes back to the launch controller to the launch pad or ground, but leave some slack from the stake point to the aft end of the rocket. If your rod is 3', i would leave at least 3' of slack.

Ideally this allows one motor to ignite, start the rocket upwards, but the wire to the igniters can follow the rocket up until the other motors light.

Some people tape the the wire to the rocket to make sure the late-to-ignite igniters are not pulled out of the motors before the late-to-ignite igniters ignite.

This video displays why it is good practice to stake your wire when flying a cluster:

http://www.youtube.com/watch?v=gzwacoEr7ns
If not staked, the wire can actually pull the rocket off trajectory until the igniters are spit out or pulled out of their motors.

Bob

[Gillard]

i did alot of clustering a few years back, and i have now moved completely away from using ignitors in the motors to using quick match.
quick match takes a little longer to set up but so far its been 100% success.

[adrian]

i did alot of clustering a few years back, and i have now moved completely away from using ignitors in the motors to using quick match.

The main snag there is that I believe the US requires an explosives licence to use quickmatch. The UK doesn't, making it a more practical alternative here.

Normally I'd echo the recommendation for a 12V controller with a beefy battery, but that's because I haven't seen Q2G2 igniters in the UK so it's either Estes igniters or quickmatch. However, it may be due to the lower power requirements of Q2G2 igniters, a stock Estes controller could fire three of them at once. Maybe try an experiment - twist three igniters together, connect them to the controller, and see what happens when you press the button - do they all light at once or do some of them delay?

Another possibility is those "straws" which may be a decent fit in Quest motors but not in Estes B6-4's. I'd use the pink plugs which would normally hold an igniter in a B6-4 regardless of what igniter it is. If the "straws" didn't hold the igniters properly against the propellant then that would cause one or more motors to fail to ignite.

Finally, I agree with staking down the controller wire, even if you're not launching a cluster. It helps prevent the wire from accidentally being pulled and taking the igniter out, whether by pulling the controller too far back or by someone accidentally kicking the wire. 3' of slack wire is more than I'd leave, maybe more like 1' unless the rocket is something like a boost glider with the motor mounted high up.

[TheAviator]

Another possibility is those "straws" which may be a decent fit in Quest motors but not in Estes B6-4's. I'd use the pink plugs which would normally hold an igniter in a B6-4 regardless of what igniter it is. If the "straws" didn't hold the igniters properly against the propellant then that would cause one or more motors to fail to ignite.

The straws are the way to go when using Q2G2s. The igniter wires are much thicker than the Solar igniters, so the pink plugs will not fit and will more than likely damage the pyrogen tip. As Adrian said, you do need to make sure that the igniter is all the way up in the motor.

As to how fast they light, it is instantaneous, even with the wimpy Estes controller. I hooked an Solar igniter to my PerfectFlite miniTimer3 powered by a tiny 6V battery (read: very wimpy current capability) to see what would happen. Not even a fizzle. I did the same thing with a Q2G2 and was startled by the loud pop. Moral of the story: Q2G2's light instantly, even with tiny amounts of current. I think the rated all-fire current is 200mA, as opposed to 2A+ for a Solar.

[terryg]

One thing that I always do is to lightly scrape inside the nozzle to ensure that the black powder is exposed.

[Rocketeer Gator]

I have a 3-E cluster that have launched once on Estes igniters.Only 2 lit so waiting on Quest igniters before I try again.Just a random thought since I have some 4FG BP is it OK to put a little BP in after the igniters then use the Estes plugs to hold it all in? Or is this against any "rules"??

[WillMarchant]

I have a 3-E cluster that have launched once on Estes igniters.Only 2 lit so waiting on Quest igniters before I try again.Just a random thought since I have some 4FG BP is it OK to put a little BP in after the igniters then use the Estes plugs to hold it all in? Or is this against any "rules"??

For BP motors you shouldn't need any "assist" with BP powder. And you shouldn't need to "scrape" the motor unless you see clay coloring on the BP grain in the motor. There are some other threads around discussing clustering and staging that talk about how you can gently get that clay off. I've not had to do that myself.

For clustering Estes igniters you'll want a beefy 12V power system. That usually means having a battery near the pad and a relay to control the power.

Also coil the launch leads near the pad so that there is some slack that the rocket can take up with it while the last motors ignite. But you probably only need that for a wimpy ignition system. Some people will suspend the leads to get the same affect. You can see the same technique used for boost gliders.

You might want to try an experiment and connect three of the igniters of your choice to the launch system of your choice using exactly the same wiring system you'll use on launch day. Try firing that and if you see the igniters firing sequentially instead of all at once you need to revise your plans.

I've had very good luck with the Quest Q2G2 igniters and BP clusters.

[WillMarchant]

While we're at it we should mention spiders like http://www.meatballrocketry.com/spider.htm and flash pans.

[Marc_G]

Hi folks, thanks for all the comments back.

I examined my video frame by frame, and it appears that the launch leads don't even wiggle when the rocket takes to the air. This tells me the two ignitors from the non-fired engines must have been yanked out perhaps by the thrust of the one ignitor that did fire its engine. The ignitors were twisted together so if one of them got pushed, it probably yanked the others out. The "straws" weren't a tight fit, but I hoped they were snug enough. Back to drawing board.

I like troubleshooting but changing one thing at a time, but this is an expensive way to go. Here's my plan:

1. I'm going to modify an electron beam controller with LED and suitable resistor to be safe to use with the Q2G2 ignitors. Got parts already.

2. I'm going to replace the wiring with a heavier gauge to make sure plenty of current gets to the pad. While I'm at it, I'll put new AAs in the thing.

3. I'll make a whip with some extra clips so that I don't have to wire the ignitors together.

4. I will test the system with video running watching the 3 ignitors to see what sort of delay between them I get.

5. If it looks good, I'll try on a rocket with 3 C6 engines, with a staked lead per above reply, and taped ignitors... if only one lights, a C should get it high enough to safely deploy the chute/streamer. Of course if all three light, that's the equivalent of 2 D's... I'll wait for it to come down.

Will post results when I get around to trying it. Might be a couple weeks.

Marc

[WillMarchant]

Cool, sounds like a plan.

You might want to wad up a piece of flameproof recovery wadding and stick one in the top of each motor. That will help prevent a non-firing motor from "back burning" if ignited by the ejection charge of one of the firing motors.

[Handeman]

I've been doing 3 and 4 motor clusters with Estes B and C motors for years. I use the Estes solar igniters and a 12V system, either mine or the clubs. I've never had a problem with motors not lighting. I use a clip whip that can handle 3 motors so when doing four, I wire some of the ignitors together.

My suggestion is to get rid of the Estes controller with the AA batteries, at lest for clusters, no matter what igniters you use. Go with a 12V system, lawn mower, garden tractor, or motor cycle battery, a car starter pack, drill/tool battery or some other source that will give you 12V at multi-amperes when launching.

[shreadvector]

Q2G2 igniters will "POP Out" of the nozzle if not secured properly.

Inserting the Estes plugs can be a problem.

Properly inserting the Quest straws that come with the Q2G2 igniters will do the trick. This means inserting the igniter and then pushing the straw in next to the igniter and pushing it in hard enough that the plastic straw deforms and is wedged in TIGHT.

I have seen many people barely insert the straws and they pop right out.

I am betting that in this case, one engine managed to ignite while the other two had the igniters pop out before igniting.

[Marc_G]

Yeah, I'm pretty sure my failure was straw-tightness related. I definitely didn't get any deformation going on! I'll give it another whack next launch date. Was hoping to have a chance on FRiday (I'm taking the day off) but forecast is rain. Drats. First rainy day forecast in a month and it's my day off.

Marc

[cjl]

Did all 3 igniters burn, or were the two remaining igniters unfired? Also, you did remember to hook them up in parallel, not in series, right?

[Mike Di Venti]

Cool, sounds like a plan.

You might want to wad up a piece of flameproof recovery wadding and stick one in the top of each motor. That will help prevent a non-firing motor from "back burning" if ignited by the ejection charge of one of the firing motors.

That shouldn't happen because there is a clay top on top of the ejection BP.
Now it may happen if one was to use a booster motor.
In all of my years flying Estes rockets and clusters I never heard anything like that before.

[Marc_G]

Did all 3 igniters burn, or were the two remaining igniters unfired? Also, you did remember to hook them up in parallel, not in series, right?

Parallel. And all 3 fired.

[WillMarchant]

From the Estes Model Rocketry Technical Manual comes this bit of wisdom:

Before installing the engines in your cluster rocket, pack the
front of each engine above the ejection end cap with flameresistant
wadding. This eliminates the possibility of one
engine’s ejection charge igniting the ejection charge of an
unignited engine and damaging the rocket. For more complete
information on clustering, see Estes Technical Report TR-6 in
The Classic Collection.

The theory is that some BP can get mixed in with the clay. Other theories say this is only necessary in old motors that have dimpled ends.

When TARC was allowing clusters we would fairly regularly see motors burn from the top. Many, if not all, of those could be due to the kids putting in booster motors because they think they only need one with ejection charge.

Sounds like a NARAM science project to me...

[SMR]

Q2G2 igniters will "POP Out" of the nozzle if not secured properly.

Inserting the Estes plugs can be a problem.

Properly inserting the Quest straws that come with the Q2G2 igniters will do the trick. This means inserting the igniter and then pushing the straw in next to the igniter and pushing it in hard enough that the plastic straw deforms and is wedged in TIGHT.

I have seen many people barely insert the straws and they pop right out.

I am betting that in this case, one engine managed to ignite while the other two had the igniters pop out before igniting.

I have had good luck with Q2G2 igniters also. Make sure it goes all the way in. I tear off a little piece of wadding and shove it in the nozzle, in lieu of either the Estes plug or the Quest straw. (This is what we did for years before Estes even HAD plugs.) Wire them in parallel and use a 12 volt relay ignition system. This is a launch of twelve D12-0's staging to three D12-3's. All fifteen motors lit.

[MrGneissGuy]

I have had good luck with Q2G2 igniters also. Make sure it goes all the way in. I tear off a little piece of wadding and shove it in the nozzle, in lieu of either the Estes plug or the Quest straw. (This is what we did for years before Estes even HAD plugs.) Wire them in parallel and use a 12 volt relay ignition system. This is a launch of twelve D12-0's staging to three D12-3's. All fifteen motors lit.

15??!!

I'm interested in how the experiments turn out as well.

On an off topic to Marc...where are you launching...is that a park, backyard, somewhere along the Monon Trail? I notice it seems most, if not all of your videos are from the same location. I'm always looking for good places to launch, and while Carmel's a bit of a drive (maybe an hour), I've driven farther for less.

[SMR]

To launch it, I used a routine Estes launch controller (4xAA batteries)

Also should add that there isn't much amperage in that controller. Years ago I tried to ignite a 3 motor cluster (very similar to yours but using Estes ignitors) with an Estes "Electron Beam" controller. NONE would light until I spliced in a bigger battery (from my son's Fisher Price Power Wheels Jeep). Then they ALL lit.

[Marc_G]

Hi guys,

I solved my cluster ignition woes by using the Q2G2 ignitors with a modified electron beam still using the 4 AA batteries but with an LED instead of the bulb and a suitable resistor in there to keep the continuity test current well below the fire amperage. I put a thread on here somewhere... here actually.

@MrGneissGuy:
I usually (OK, always so far) launch from the central hill in West Park in Carmel (just a couple blocks west of the intersection of Towne Road and W 116th street). The hill is at the center of a 500 foot radius clear circle of grass. There are a few small trees in rows but nothing threatening. There's also an extended recovery area of brush in most directions before you get real trees.

I'm also investigating launching from the field of Shamrock Springs Elementary which is up in Westfield near 161st and Spring Mill.

I do only LPR at these very public locations. Always looking for better fields. Haven't joined any local clubs or anything; I've only been a BAR for a few months. :-)

Marc

[jms]

I had a cluster failure myself this weekend, and to be honest I attribute it to either me screwing up the wiring (human error is typically first) or not enough juice in the portable battery pack.

Normally I use my Interlock controller hooked directly up to my vehicle, but this time I used a 12v portable pack that a fellow brought with him and admittedly he had only been able to charge it on the way to the launch. I had 100% success before, and only two motors fired this time around.

This is the FUN of clusters though! It's a challenge, and makes it that much more rewarding when they all fire as planned. Don't get discouraged.

[shreadvector]

What kind of motors and igniters? If they were igniters that require a lot of amps, then that could be the big problem when using a battery with unknown current delivery capability.

I had a cluster failure myself this weekend, and to be honest I attribute it to either me screwing up the wiring (human error is typically first) or not enough juice in the portable battery pack.

Normally I use my Interlock controller hooked directly up to my vehicle, but this time I used a 12v portable pack that a fellow brought with him and admittedly he had only been able to charge it on the way to the launch. I had 100% success before, and only two motors fired this time around.

This is the FUN of clusters though! It's a challenge, and makes it that much more rewarding when they all fire as planned. Don't get discouraged.