Cluster Launch Power

you might look into aquiring some 'limp noodle' battery wire, I know that castle creations gets some in 8ga (and its a real pita to solder connectors on it too).
rex

The cluster box worked perfectly at the 7/17/10 CMASS Amesbury, MA launch.

Fired 48 motors in 3 clustered flights with no ignition failures, using Rocketflite ML igniters for almost all motors.

First flight was an 18" Applewhite saucer "Saucer of DOOM" on 7x D12-0 motors.

Made series strings of 3 Rocketflite ML igniters and wired 3 of these in parallel. Two extra igniters used for a test to build confidence for the following flights.

Igniter net resistance about 0.8 ohms. Box pushed about 19A at 16V into this or about 300W.

Second flight was an upscale FlisKits Thunderbird on 11x motors
1x ProX F30 White (24mm 3gr - new motor)
3x Estes E9
7x Estes D12
Thread with more info and pictures here: https://www.rocketryforum.com/showthread.php?t=8817

Used 2 series strings of MLs 2 long for the outboards, 2 series strings 3 long for central ring of motors, and ProX supplied ematch for the F30.

Total igniter resistance about 0.36 ohms. Box supplied over 40A at over 15V or more than 600W.

Third flight was the TOGinator on 30x motors
1x ProX I236 Blue (38mm 3gr)
2x ProX H133 Blue (29mm 3gr)
27x Estes D12
1200 Ns full J cluster
Thread with more info and pictures here: https://www.rocketryforum.com/showthread.php?t=13352

Used 3 series strings of MLs 2 long, 8 series strings 3 long, plus redundant ProX ematch for central I motor.

Total igniter resistance 0.16 ohms. Box pushed 85-90A at about 14V or 1200W to launch this.

As can be seen in the second TOGinator picture, sparks from the ignition of the upper motors lit the tops of some of the lower motors, causing the barbecue effect. It could be said that there were 50 ignition events in that flight despite the fact that there were only 30 motors.

Before these three ignitions the no-load battery voltage was 16.78V, after it was 16.75V, so lots of battery capacity left.

holy

crap

:eyepop:

Used the cluster box again at the end of July and twice in August to fire the Turbine Rocket Saucer. This is an original design inspired by FlisKits' Frick-n-Frack and Applewhite's saucers, combining clusters with saucer and helicopter design features. More pictures plus flight details and movies here: https://www.rocketryforum.com/showthread.php?t=13727

The "TRS" was fired 8 times at these 3 launch events. Every launch was powered by clusters of (mostly D) Estes 24mm motors - 7 launches on 4x motors and one on 8x.

Used Rocketflite ML igniters for all flights. For some launches, igniters were wired all in parallel, for others in series strings two long then assembled in parallel (to reduce current load).

First 3 pictures show the 8 motor cluster flight wired in combined series and parallel. Last two pics are a 4x motor flight with motors mounted in a more canted position to maximize spin.

36 motors were installed in these 8 flights and all motors were fired.

Cluster box has now fired 84 motors in 11 flights with no ignition failures.

The cluster box was featured in the Jan/Feb 2012 issue of Sport Rocketry in an article titled "Lightning Cluster Box, Electric Sledgehammer: 1300 watt output from a six-pound box!".

Got questions from folks looking to build their own. What follows is some additional info that may be helpful. Please feel free to post here or private message me with questions.


Wiring Diagram:

The attached image is a higher resolution copy of the wiring image in the article. I never drew up a neatly done wiring diagram, but this image shows all wiring connections.


Big Relay:

Polarity needs to match the relay's instructions going onto the activation coil for the big relay.

The part number I used was SS-598. Partsgeek does not seem to carry it anymore.

It can be found here, but the price has gone up: https://www.autopartswarehouse.com/...ardQQStarter_SolenoidQQ19921997QQSISS598.html

It is likely that any relay specified for a 1990 Ford Crown Vic would work well, because they are rated for 200A and have a clamping diode, reducing the voltage spike created when the big relay is de-activated.


Fuse:

The black part with copper tabs is a 175A fuse that I picked up at AutoZone: https://www.autozone.com/autozone/parts/Bussmann-Fuse/_/N-9ciet?counter=68&itemIdentifier=32346_0_0_

to protect against a short.

Late last year the fuse failed, broke inside without being exposed to high current, and it is no longer part of the circuit.

For a club launch system that is likely to be handled by a number of people, a fuse would be a good precaution. I picked this one because of the high current rating and I could connect to it directly with screws, so no fuse holder or extra wiring was needed.
.

If it were me, I'd build a complete launch system and work with the BoD to set it up for your flights. If they have to push the button, then so be it, put the controller on the LCO's table.

Clustering requires patience, time, and attention to detail, as you well know, so hurrying to setup your project on a club pad is not the way to go.

I have been to "other club" launches with torture racks. Hate 'em. uke: We fly misfire alley in both of our clubs here in Phoenix and it works soooo much better, and everyone builds their own GSE, which is half the fun. we have some cool pads and controllers out here. You misfire, you simply recycle and fly when your card comes to the bottom of the stack again (we load a box top down and pull the oldest out a slot on the bottom) Nobody waits...

I have launches 2 twin engine rockets and a 3-engine rocket, using a 24 volt battery, 35' of stereo wire and a simple button. They have worked perfect so far. The 1 safety system is the wire can connect/unconnect directly from the battery.

Here are the rockets...

2012 Year-End Update:

Just completed a LOT of updates to my rocketry website including many pictures and videos of fun cluster flights: www.bpasa.com

Have been using the cluster box for most of 3 flying seasons with excellent results.

Starting 7/2010 and continuing through 12/2012, the cluster box has been used for all my clustered flights firing 5 to 30 igniters at the pad, and most flights firing 4 igniters:

Year - Cluster Flights - - - - Motors - - Number
- - - - using Cluster Box - - Loaded - - ignition failures
2010 - - - 22 - - - - - - - - - 154 - - - - 1
2011 - - - 16 - - - - - - - - - 140 - - - - 2
2012 - - - 23 - - - - - - - - - 176 - - - - 1
Total - - - 61 - - - - - - - - - 470 - - - - 4

Sorry about all the dashes, couldn't get a clean table to show up here.

Bottom Line:
Using the cluster box and Rocketflite igniters has produced 99.1% successful motor ignitions over 3 years, firing 466 of 470 motors attempted in 61 clustered flights.
The combination of the cluster box's very high power output with high quality Rocketflite igniters has been very effective at successfully igniting clusters.

Notes:
1) For flights firing 6+ igniters I normally wire igniters in series strings of 2 or 3 and then combine these in as many parallel sets as needed.
Please see bpasa.com Rocketflite and TOGinator pages for pictures and more information on combining series and parallel wiring of igniters.
This is done to balance voltage vs. current demands of clustered igniter system.
2) Clustered flights in 2012 used Rocketflite's new CF (ClusterFire) igniters, which use their lower current MF wires with a pyrogen that burns almost as long as their excellent ML igniters.
3) Also used CF igniters to fire all 18 deployment ejection events with no failures in 2012.
4) Clustered flights in 2010 and 2011 used Rocketflite's ML igniters.

30 engine cluster fired by cluster box:

[video=youtube;M-3dYlUGUyE]https://www.youtube.com/watch?v=M-3dYlUGUyE&feature=player_detailpage[/video]