Cluster - how big?

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Sooner Boomer

Sooner Boomer

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What's the biggest cluster (highest number of motors) you've successfully gotten to ignite at once? I've got a 7-engine Fat Boy I've been trying to light up. So far, I've gotten 4, 5, and 6 motors to light off at once, but never all 7. I've found it takes a LOT of current to get them all going at once (wired in parallel). We tried our wireless system for the first flight but it just wouldn't light even one. We tried using a flash pan with limited results (4 lit). I've been using "normal" Estes igniters. Last time (6 lit) I think I used the new silver igniters (Star Fire or somesuch?). I've been thinking about putting a small dab of starter mix on each nozzle and using a better flash pan.

Here are some videos of flights:

at Sayre (1st flight) 4 motors lit


at Argonia - AirFest 27 - no video yet - 5 motors lit

at Pawhuska (High Fronteer) 6 motors lit
 
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I did a simple low power cluster of 5 Q-jet 18mm D motors and out of 3 tries only 1 was 100% successfull with all motors lighting.
 
I’ve gotten 7 C-6s to light using an 11.1v lipo battery to provide the current. I’d have to check what the C rating on that battery was but I don’t think it was anything too crazy. It was also using standard Estes igniters.
 
There was jus a 313 C-motor cluster flown at BALLS with a cental J-motor hybrid, 299 of the 313 motors lit! Sorry cant find the Facebook link to it now....hate FB. My personal best cluster 4x AT E18W
 
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LOC Ultimate, 6x F42 + 1x H180. All using custom igniters (magnelite) on a 12v SLA relay based club controller. All 7 on the ground but the F42s came up to pressure quickly and launched the rocket. The H180 didn't come up to pressure until about 50 ft above the pad. All 7 igniters wired in parallel.
 
Sooner Boomer said:
What's the biggest cluster (highest number of motors) you've successfully gotten to ignite at once? I've got a 7-engine Fat Boy I've been trying to light up. So far, I've gotten 4, 5, and 6 motors to light off at once, but never all 7. I've found it takes a LOT of current to get them all going at once (wired in parallel). We tried our wireless system for the first flight but it just wouldn't light even one. We tried using a flash pan with limited results (4 lit). I've been using "normal" Estes igniters. Last time (6 lit) I think I used the new silver igniters (Star Fire or somesuch?). I've been thinking about putting a small dab of starter mix on each nozzle and using a better flash pan.

Here are some videos of flights:

at Sayre (1st flight) 4 motors lit


at Argonia - AirFest 27 - no video yet - 5 motors lit

at Pawhuska (High Fronteer) 6 motors lit
Click to expand...


Wish I'd known that was you with the FatBoy, I'd have said hello! Next time!
 
I launch my 7 motor Cluster Ducks at every launch, original and upscale, and never have a motor not go. The two keys are:
1) Use a relay cluster box that dumps an entire LiPo when the button is pressed
2) Use MJG igniters (wired in parallel) for both black powder and composite motors: https://electricmatch.com/rocketry
 
The Cluster Box is based on this classic design: https://bpasa.com/Cluster-box.htm
The only changes I made were to add a digital voltage display that I already had laying around, and a big rotary switch to isolate the battery when not in use. I also used somewhat larger gauge output wires and clips that I already had. Mine fits in a wooden cigar box. The hardest part is remembering to retrieve it so as to not confuse the next person to use that pad!
 
3 F-67's and 3 F-25's on two occasions in the same 3 motor rocket. I had an odd igniter in one of the F-67's and it came up to pressure about 20' in the air.

The three F-25's went fine.

I've got a Magnum with a 54mm surrounded by six 29mm's. That one is probably going to get an I-280DM and 4 H-115 DM's. Weather permitting.
 
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Motoreater, 54 & 8 29s, Ultimates, 7 24 or 29 or 38s, Fat Boy, 12 13mm. Biggest cluster was the Fat Boy on 4 Rx C20-8s and 8 A3s. Dipped starters for the C20s and fuses to the A3s lit from the C20s. For the pictured flight, these are all A3-4s Only the center 3 go through the top CR, the rest are vented between the motor tubes. All are still flyable, and except for the Fat Boy, all have electronic ejection. MUCH safer if all the motors don't light.
DSC00088.JPG Rear.jpg Fuse1.jpg
 
I've flown my Hydra VII twice - both times all 7 ignited
Used part of my stash of Q2G2 the first time and some enhanced Estes igniters the second time
 
T34zac said:
I’ve gotten 7 C-6s to light using an 11.1v lipo battery to provide the current. I’d have to check what the C rating on that battery was but I don’t think it was anything too crazy. It was also using standard Estes igniters.
Click to expand...
I used to have a FatBoy with 7 C6-7 motors. Got them to all light 3 different times using std 12V launch system and Estes igniters of the day.
 
First you need to throw those Este's ignitors in a dumpster. I use flashbulbs for BP clusters. I have lit 13 at once.
 
I would have to double-down on Dugway's posts above. If you are into clusters, make a Cluster Box. Nothing beats having all that 4S LiPo goodness at your disposal when the button is pushed.

Also, he is right on the MJG igniters if you are using BP motors. I have done up to 12 motor clusters with those igniters and have never had one not light. And, the long wires make it so much easier to wire up the cluster.

For high power clusters, I can't imagine doing it without Pyrodex pellets. The potential for a mishap goes way up with high power clusters - you really want them all to light and light fast. If you use Pyrodex, you can use just about any initiator. I have 29mm, 38mm and 54mm clusters and use Pyrodex for them with 100% initiations. One of my next projects is an 8" rocket with a 4 x 75mm cluster, just waiting on some custom fins from Tim at Wildman to start that build.
 
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My experience has been that MJG matches dipped in Boron/Potassium Nitrate/Viton are very reliable and fast. In the last year I have had zero failures.

My experience with the packaged igniters has been different.
 
Daddyisabar said:
Eight in the Lancaster. 4 D12 3 in the engine nacelles, 2 C6 0 tractor, canted and plugged in the cockpit and two mid body canted and plugged C6 0. Widely spaced motors in pods are cool! Canted tractor motors rock! Put them all together and have loads of ignition fun!

View attachment 483912
Click to expand...

This.Is.EPIC.COOL.
 
I have to comment here. There's a HUGE difference between gluing a bunch of motors together and whacking that mess on the bottom of a rocket, vs a rocket that has conventional motor mounts for each engine, and they all fit inside a body tube. The first example is a stunt.
 
I got 6/7 FJ Q-Jets to light on a single flight, using a 12V with no special relaying or boost.
 

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