LOC 4-29 ss - cluster igniter question

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csoechtig

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My latest build is a LOC Precision 4-29 ss. This is a 4x 29mm CLUSTER rocket. It is a pretty clever design with four fins that fit into the grooves between the motor tubes, which extend two feet aft of the end of the main body tube. I modified the rocket (only slightly) to allow for dual deploy. Also, I plugged the forward ends of the MMT tubes and used a #10 threaded rod for motor retention. It requires a washer and wing nut for a firm hold.

LOC 4-29 ss 1.jpg

LOC 4-29 ss 2.jpg

This is my first cluster motor build and am looking for tips/advice on igniters. The maiden launch will be relatively tame with 2x G64W motors. I plan to use 2 twiggy (by Quickburst) igniters. I've used these on many single mid-power flights with great success.

QB.JPG

According to their website, Twiggy igniters are reliable for up to 3x 29mm clusters. So, what do you suggest when I step up to 4x motors? I've read a lot about making your own igniters or converting/dipping e-matches. However, I have zero experience with this and would prefer to keep it simple. Also, it seems like most homemade igniters would be too large in diameter to fit in the narrow grove of a 29mm commercial motor.

Any suggestions would be appreciated.

Thanks,
Chris
 
My latest build is a LOC Precision 4-29 ss. This is a 4x 29mm CLUSTER rocket. It is a pretty clever design with four fins that fit into the grooves between the motor tubes, which extend two feet aft of the end of the main body tube. I modified the rocket (only slightly) to allow for dual deploy. Also, I plugged the forward ends of the MMT tubes and used a #10 threaded rod for motor retention. It requires a washer and wing nut for a firm hold.

View attachment 182717

View attachment 182718

This is my first cluster motor build and am looking for tips/advice on igniters. The maiden launch will be relatively tame with 2x G64W motors. I plan to use 2 twiggy (by Quickburst) igniters. I've used these on many single mid-power flights with great success.

View attachment 182719

According to their website, Twiggy igniters are reliable for up to 3x 29mm clusters. So, what do you suggest when I step up to 4x motors? I've read a lot about making your own igniters or converting/dipping e-matches. However, I have zero experience with this and would prefer to keep it simple. Also, it seems like most homemade igniters would be too large in diameter to fit in the narrow grove of a 29mm commercial motor.

Any suggestions would be appreciated.

Thanks,
Chris

Twiggies would do well with a cluster box that can provide more current directly to specifically your rocket.

I haven't personally experimented with clustering on low current igniters yet so that is all the advice I can offer.
 
AeroTech FirstFires work great or, even better, check out www.rocketflite.com. Get ClusterFire pyrogen and FS-12-LA or ML wires. These are great for clusters and of course, using a relay with a 12 V system is best. You also can use their ML pyrogen and igniter wires but they require a little more juice. Definitely need a relay for those.

Also always remember to leave lots of slack in the leads (extra if possible) and/or attach the igniter leads to the rocket so that the clips can fly free but the igniters can fly with the rocket until they lioght the motors up.
 
+1 for what Marcus says- I love the the pre-made nicrome wraps from Rocketflite and a single dip fits most G motors. For added insurance on a cluster, I go with Cez motors due to the BP pellet helping to get simultaneous fire going.
 
I plan on using CTI motors in my 2x29mm cluster. In my experience, CTI motors light easier because of their BP pellets. Of course, I haven't tried a cluster of them yet.
 
I second (or third) cluster fire/magnelite. I've had terrible luck with first fires.

Remember some propellants are harder to light than others. Blues are generally easiest. Everything else I get the second motor coming up after the rocket leaves the rail. Gives a nice little wiggle on the way up.
 
I placed an order for the ClusterFire (CF) Pyrogen Kit and 2 packs of MF- 24 wire. I got the extra length based on David's feedback.

I might have more questions when the kit arrives and start making igniters. Until then - thanks for the feedback!
 
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There's enough dip to literally make a couple hundred ignitors. If you have a safe place to store it, it will last a long time.

I've used magnelite with ML-24's to light I200w, G76G, and G138t motors. They don't disappoint. It also helps to scuff the top grain a bit when you build the motor. Leave the dust in the core.
 
I have successfully launched my Viper 4 (24mm smaller brother) on several different CTI motors with no modifications to the igniters. Just twisted the leads together in parallel. No failures to date, lite all four motors each time.


Because I am addicted, this is coming from my phone.
 
Good point, diz. To take that a step further, you can also paint a very thin layer of that pyrogen on the top grain. I've done it down to LMS F20Ws.

Just curious, what was your bad experience with FirstFires, Diz? I know on your 2x29mm cluster rocket you have mentioned a couple of late or misfires but I can't recall what igniters you used for those flights. I've used them several times but the most I tried was a three motor cluster. I've had success with 1xI280DM + 2xH178DM, 2xH220Ts and 2xH195NT. I plan to try 4 with the mini first fires when I get my hands on some of the new EconoMax's for a 4xG74W cluster in my own 4-29.
 
I've on ff jr f42T, first fire jr on G80T, but failure on G76G. Granted green is hard to light quickly, but I've stayed away from first fire since then.

Single motor launches I've had a few FF fail/sputter, but never on the magnelite. So I just go with those now.
I'd be comfortable lighting blue with them, but not much else when I have the option.
 
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Gotcha. You will notice the clusters I tried them on are all easy to light as well. Blue obviously, but Aerotech Sparky is easy to fire up too. That is dark matter, not metalstorm white, which is harder.
 
I really need to finish up my 3x29 1x38 mini magg and load it up with some DM, maybe a blue core
 
BTW - - if anybody has a thread (or pictures) of prepping/mixing/dipping the Cluster Fire igniters, I would GREATLY appreciate it. I'm sure when the kit arrives, it will make sense. But, I'm looking at the directions on-line and they are a little confusing.

THANKS!
 
If it's like the magnelite, there's a paper funnel to mix some powders into a jar. Then you add the liquid until it hits the right consistency. Mix it up and then dip. Everything is included, and once it's in front of you it all makes sense.
 
I've had success with copperheads of all things on f42T, first fire on G80T, but failure on G76G. Granted green is hard to light quickly, but I've stayed away from first fire since then.

Single motor launches I've had a few FF fail/sputter, but never on the magnelite. So I just go with those now.
I'd be comfortable lighting blue with them, but not much else when I have the option.

I have used FirstFires on G138T clusters without problem, but only in pairs. G76s are less good.
 
F42T, ff jr
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G80T FF Jr
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G76G FF Jr
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G138T magnelite (note less photos)
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G76G magnelite
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I200W magnelite (ML-24)
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I like clusters. :) Longer wires help. I've experimented a bit with "heavy" dipping vs light. It seems to have little effect. The only failures with magnelite I've had were on someone else's G64W that had swollen so badly it just wouldn't light. Everything else rips. Less dip makes them easier to fit into G sized slot-loading motors.
 
Have you considered flying this on a cluster of 4 Estes F15 BP motors? Those and Q2G2 should make for a nice launch that is just about bullet proof from the motor ignition perspective.
Personally I would go with a 4 motor cluster using Blue Thunder propellant, or something similar that ignites quickly and use a launch rail, rather than a rod.
A 50% ignition success on a 4 motor cluster should have a more nominal flight as compared to 50% ignition success on a 2 motor cluster.

Good choice on your decision to add electronic deployment, as it will help to save your airframe when things don;t quite go as planned.

John
 
Have you considered flying this on a cluster of 4 Estes F15 BP motors? Those and Q2G2 should make for a nice launch that is just about bullet proof from the motor ignition perspective.
Personally I would go with a 4 motor cluster using Blue Thunder propellant, or something similar that ignites quickly and use a launch rail, rather than a rod.
A 50% ignition success on a 4 motor cluster should have a more nominal flight as compared to 50% ignition success on a 2 motor cluster.

Good choice on your decision to add electronic deployment, as it will help to save your airframe when things don;t quite go as planned.

John

John,

Considering I plugged all 4 mmt tubes, I can't use single use motors. My logic for plugging them was so I could fly with 2 motors and not worry about drogue ejection charges escaping thorough the unloaded tubes. Therefore, I need to use reloadable motors with no BP.

I definitely wanted dual deploy for safety reasons. If the rocket is loaded with 2 G's and only one motor ignites, it will have a very low thrust to weight ratio and might only reach 300-400 ft. Electronic ejection guarantees separation at apogee. If apogee is below the pre-set altitude for the main, the main will fire 1 second after drogue.

Chris
 
John,

Considering I plugged all 4 mmt tubes, I can't use single use motors. My logic for plugging them was so I could fly with 2 motors and not worry about drogue ejection charges escaping thorough the unloaded tubes. Therefore, I need to use reloadable motors with no BP.

It won't work with BP motors obviously, but you can take AP SU motors and remove the BP from the well, seal it with some wadding and tape, and be ok. (someone will probably jump in and call this motor modification, but I don't buy that)
 
My 4-29SS on 4 F15's, dual deploy, got 1100 feet. Nice flight.

You can use tape thrust rings and friction fit - not too tight - and they will eject when the ejection charge fires.
 
I dipped 24 igniters yesterday and conducted a test with 4x on a clip whip... I was pleased that all 4 fired up on a 12 volt battery. However, you can clearly see that igniter #2 fired up about 0.5-1.0 second before the other 3.

I still think this would be OK. Even if one G motor fired up right away, it would be a slow acceleration up the rail (considering the rocket will weigh +/- 5lbs). This would have given time for the other 3 to ignite. What do you think?....

[video=youtube;w6s4qoHcNCM]https://www.youtube.com/watch?v=w6s4qoHcNCM[/video]
 
Interesting. Maybe that initial one had a lower resistance for some reason. I don't know if they have anything to do with it, but I would eliminate the clip whip and just twist your wires together. You should have plenty enough slack to do that.
 
The first launch of my 4-29 SS was a success. I flew it on 2x G64W AT reloads using 2 freshly dipped Cluster Fire igniters. It peaked out right arounf 1000 ft. Next flight will be on 4x G64W's...

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[video=youtube;Plf6Wt2PZs0]https://www.youtube.com/watch?v=Plf6Wt2PZs0&feature=youtu.be[/video]
 
They were the ML 24's. Worked great!


Sent from my iPhone using Rocketry Forum
 
I have the 4-29SS. Flown on 2-G64 and 2 estes F18-8 using the estes motors for ejection. dang cool flight. Also flown twice with just 2 G64s and twice with 2 G53s.
I used supplied aerotech igniters on the Gs and estes sonic igniter on the Fs (continuity checked on the pad) Although I probably wont mix the motors like that again. It was probably luck the motors all lit and we had a straight launch. Looking forward to more great cluster flights with this one..Have fun!
 
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