Yup - Another Thread on Clustering

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Hospital_Rocket

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Ok all you cluster gods, I'm hooked.

So, how do you cluster with RMS motors?

Both of my cluster birds (LOC VIPER3 & VIPER4) seem to preclude clustering as the aft closures would get in the way.

A
 

Donaldsrockets

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I would HIGHLY reccommend that you get some good aftermarket igniters such as Magnalites to insure a relaible ignition.

Also when it comes to composite clusters, AT's Blue Thunder propellant would offer the most reliability as it ingites almost instantly.

Another person that you might want to talk to on here would be n3tjm. He knows quite a bit on how to ignite composite clusters.

Good luck.
 

Hospital_Rocket

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Gee

I was thinking a patriotic 3 engine cluster would be really cool. A RL, a WL, and a BT.

Yes I was planning on launching from behind a pile of sandbagss!:D
 

hokkyokusei

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Pro38 motors (and the supplied igniters) are reputed to be good for clustering, though I'll admit it's not something I've tried.

Is the wall thickness of the LOC motor mount tubes that thin then? Seems strange as this _would_ pretty much limit you to single use motors. I'm pretty sure that the wall thickness of PML phenolic motor mounts is such that RMS motors can be used in clusters.
 

BlueNinja

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I vote for magnelites.

I think it would be more of a red and white cluster, blue thunder doesn't really have a flame. Maybe it does in the H and higher impulse.
 

marvSRG

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Pro38's and the supplied ematches are great for clustering. Midpower composite clustering is a bit harder though. ML-12 Magnelites work, but not more than 4 can be used without beefing up even a 12V launch system. My favorite MP cluster igniter were the Trailing Edge Technologies "Fire in the Hole" igniters, but I don't know if they are still made as the owner, Jim Turner, died a couple years back. I belive the company is still in business, but I don't know if the igniters are still made. They were great...good pyrogen and a tungsten bridgewire. Ken at Performance Hobbies showed me some tiny igniters he has called "Fireflys" They appeared ideal for those small nozzled composite motors, and for MP composite clusters. He gave them to me to use in my Ultimate to airstart some motors, but I ditched them b/c a standard 9V battery wouldn't light them...but I'm sure a 12V system would be fine. Just test first if you use them. Plus, I wasn't thinking and used a standard 9V, which, yes, sometimes work, but I'll try a 9V NiCad next time. Quickburst is also another igniter that may work...but no more than 2 or 3 at a time there as they, like Magnelites, suck up the juice. And they are a bit worse than Magnelites. 3 would be pushing it with those. I did a twin F50T cluster in my 4-29SS and used QB Twiggys. The flight was great, but padcam video showed that one F50T lit late. So that's my reccomendations...I can't think of anything else. I wouldn't reccomend Ignitermans as I've heard too many cluster problems with those. Just remember to be wary of your power on QB's and Magnelites. 3 is enough for QB's without a relay or anything of the sort, and for Magnelites 4 is the max without a relay....hey Doug- you did 7 Magnelites, right? Didn't you use a relay on that?
Hopefully he'll answer that one. Well, I hope that helped. Good luck with the cluster!
 

hokkyokusei

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Originally posted by Blue_Ninja_150
I vote for magnelites.

I think it would be more of a red and white cluster, blue thunder doesn't really have a flame. Maybe it does in the H and higher impulse.

Blue Thunder doesn't really have much smoke, but there's plenty of flame:
 

WRX03

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New here so don't get mad when I say this. Back in the 60/70's when we did clusters we but an eyebolt in the rocket and the saw horses we used for launching. We tied a rubberband between the rocket and launch pad in direct path of the rocket's exhaust. The rubber band would hold the rocket for a second until it burnt through or broke giving all/most of the engines time to ignite. Okay you can shoot me now :kill: We were kids, but it worked very well.

 

BlueNinja

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Oh, I was thinking of the MPR motors. Those i could not see any flame whatsoever.
 

marvSRG

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Oh, I was thinking of the MPR motors. Those i could not see any flame whatsoever.
True- no visible flame, but there's some invisible flame, and some flame drowned out by the daylight. You'd be suprised at what an E28T looks like at night. That spike of orange is much bigger and brighter, there's sparks from the burning liner, and sometimes you can catch a bit of blue. There's plenty there to do some damage if tied down.

We tied a rubberband between the rocket and launch pad in direct path of the rocket's exhaust. The rubber band would hold the rocket for a second until it burnt through or broke giving all/most of the engines time to ignite.
That's still one possiblility, yet I've reversed that in a way. As long as you use the same igniters, they'll all light at the same time...it's just that some motors will light faster than the others, and if nothing is retained, they'll move the rocket, and pull out the other igniters as they are burning, and not giving them time to light the other motors. Every time I cluster (especially when I'm mixing BP and composite) I try to retain the igniters to the rocket in some way. As long as you wire them correctly and make sure the clips will be pulled off and not with the rocket, then the igniters will light all together, and if there are any late motors then the clips will be pulled off as the rocket lifts and the igniters of the unlit motors can stay in them and fully burn and ignite the motors.

I was thinking a patriotic 3 engine cluster would be really cool. A RL, a WL, and a BT.
I just may do this with 38mm I motors @ the Freedom launch this year in my Phoenix. I would position it so that I'd have say an I300T, then a Pro38 I something (WL's too bright and would drown out the other motors), and then an I something Redline facing the crowd. I'd retain the igniters and also put pyrodex pellets in the top grains of the AT motors to get instant or near instant on ignition of all motors.

Fun stuff:cool:
 
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