Can I modify a Estes Electron Beam controller for clusters?

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grimlock3000

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I have two Estes Electron Beam controllers. One is what I use for my single engine LPR flights, the other one is sitting in an Alpha III Starter set I bought for $10. Is there any wiring mods I can do to make the Electron Beam safe for clusters?

Or should I just scratch build a 12v launch controller? I have a starter box for my RC car with a 12v battery inside. I could use that battery as a power source and make a switch and firing lock from Radio Shack parts.

I want to try a 2 or 3 motor kit like a Deuce's Wild or a Thrustline A-SLAM.
 

sandman

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Join the NAR. When you join you will recieve a magazine with an article for modifying the Electron Beam launcher for use with a 12v battery.

The modification is cheap and easy.

You do have to buy some battery clip a piezo buzzer (a 12v one to replace the lamp) Oh...yea...and a 12v battery!

sandman
 

grimlock3000

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Here is what I have to work with:



This is the inside of the starter box I use for my nitro RC car. The black thing is a high torque electric motor that can turn over tight nitro motors like nothing. With enough juice to crank over nitro engines, I figure it should be able to spark some launch igniters. The starter box gives me a handy way to tote around a 12v lead acid battery. The plugs on the side are standard sized banana plug jacks with an always on 12v connection so I can just plug in launch wiring when needed:



The switch on the side just disconnects the electric motor so I would always leave it off for rocket use. Here is a shot of the battery:



I already have the banana plugs for the side and plenty of thick speaker wire. Is this as easy as running the 12v jacks on my starter box to a launch button and safety key, then running leads out from there to a clip whip? Then for launch I just turn the key to arm the wiring, then press the button to connect the circuit?
 

sandman

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OK then. This is all you have to do.

I can do drawings for you later if needed.

Go to Radio Shack and get a 12v piezo buzzer. Solder the leads from the buzzer to the + and - leads for the lamp (throw the lamp away).

Solder one lead to the battery + and one to the battery - inside the Electron Beam launcher.

Each one of those leads should have a banana plug on the free end to attach to your battery box.


When you hook up the leads, wire the clips to an igniter and plug in the launch arm key the peizo buzzer will screem to let you know you have continuity.

Count down and launch!
:D

sandman
 

grimlock3000

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OK, I got inside the Electron Beam and it does not look that beefy. Would I be better off to not use an Electron Beam at all and just use a custom switch box with two sets of wires? One set of wires with banana plugs for the 12v source, and the other set would go to the clip whip.
 

sandman

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Well, the Electron beam unit can hold the piezo buzzer, it has the launch key and the fire button already on it.

But yea you could just replace it.

sandman
 

grimlock3000

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Initially I was just thinking about being able to launch a Deuce's Wild and figured the Electron Bean could be messed with to get it working. Now I am just a bit concerned about the Electron Beam being a weak link if I ever go for a cluster of Ds or when I get a MPR rocket with a G80 or something. I do not want to fry anything or have a launch failure, then come back here and have people say, "You tried launching XYZ with a modified Electron Beam? Duh, of course it messed up, those tiny wires can barely light a C." If it is something I would end up replacing anyway, I would like to make sure I do it right this time :)

Thanks for the help btw! I am hoping to get a new launch controller going by this weekend, then I can go field test it with some single engine launches and start thinking about what cluster rocket I should start out with. The rocketry addiction is really setting in, I want more :D
 

bobkrech

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As Sandman says, the Estes Electron Beam can be readily modified to operate with a 12 volt battery, but this is not necessary for any kits that Estes has sold, the largest of which is a 3 motor cluster.

You might want to go to the Estes Educator site, https://www.esteseducator.com/cfusion/publications.cfm to get some further info.

Estes ignitors have a resistance of 0.8 ohms and require 2 amps to fire, so using Ohm's law we can calculate minimum all fire voiltage of only V=ri=0.8x2=1.6 Volts! The Estes Electron beam launcher used 4 AA batteries supplying 6 volts, so voltage is not the problem. Current is!

Using Ohm's law, we can figure out the current that can be supplied by the launcher into an ignitor. It will depend on the internal resistance of the batteries, the resistance of the wires, and the switches, and the ignitors.

A fresh Duracell AA battery has an internal resistance of 0.12 ohms, so the resistance of 4 batteries in series is about 0.5 ohms.

https://www.duracell.com/oem/primary/alkaline/mn1500.asp

The resistance of the controller is probably 1 ohm or less, even if the clips are old.

Let's solve the problem for 1 ohm, and then for 0.5 ohms, and then for the actual values.

The maximum curernt draw is a zero ohm ignitor. This assumption is close to what you get with a cluster. (The Resistance of 1, 2, 3, 4 and 5 Estes ignitors are: 0.8, 0.4, 0.26, 0.2, 0.16 ohms respectively.)

So to calculate the delivered current we again use ohms law solved for current: i=V/r=6/(0.5+1)=6/1.5=4 amps, so if the launcher resistance is 1 ohm, you will definately fire 1 ignitor, probably fire 2, but definately not 3.

If the launcher resistance is 0.5 ohms, i=V/r=6/(0.5+0.5)=6/1=6 amps, and you can fire definately fire 2 ignitors, and maybe 3 ignitors.

The actual resistance of the Estes Electronbeam Launcher is about 0.36 ohms if the clips are clean. so with fresh standard AA batteries, you can deliver i=V/r=6/(0.5+0.36)=6/0.86= 7 amps, or 2.3 amps per ignitor, so all 3 fire.

A pretty good minimum cost engineering design, since the largest cluster sold by Estes is a 3 motor cluster.

Read https://www.esteseducator.com/Pdf_files/1924_launch.pdf and you'll learn how to answer these questions.

Bob Krech
 

Karl

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I would just make my own launch controller , then if anything goes wrong , you will be able to find the fault because you know where everything is , and how everything works.
-Karl
 

JRThro

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I was just searching for threads on modifying the Estes controller, and I found this one.

I'm building a 2-motor cluster rocket, which is what prompted my search.

From what I've read, the 6V Electron Beam is not all that reliable for launching even 2 motor clusters, so I'm going to look into modifying mine for 12V operation. Not as shown in the NAR member guidebook, but by wiring a second set of 4 AA batteries in series with the existing internal set of 4 AA batteries.

I have a 4 AA battery holder that I bought at Radio Shack last year, and that's what I'm planning to use as an "add-on" to the Electron Beam. Probably will mount it on the bottom of the Electron Beam, at first with velcro pads until I'm sure it works.

Now I need to find my NAR member guidebook to see how the author of the article opened up his Electron Beam.
 

grimlock3000

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Wow, this thread came back from the dead :) Anyway, I never did anything to an Electron Beam to work with clusters. I took one of the Ester controllers apart and it is total cheapness in there, very low quality and not something I wanted to work with further. While I am sure it could have worked, I am more the type of person to overbuild something so I KNOW it will work, even in non-optimal conditions. I ended up with a homebrew controller, fairly cheap, can easily handle clusters, and it works way better than an Electron Beam even for single engine launches:

https://www.rocketryforum.com/showthread.php?s=&threadid=16641

If you want to go one step further, I would really reccomend the DIY approach. My controller was fun to design and put together, and very satisfying to use.
 

JRThro

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Originally posted by grimlock3000
Wow, this thread came back from the dead :) Anyway, I never did anything to an Electron Beam to work with clusters. I took one of the Ester controllers apart and it is total cheapness in there, very low quality and not something I wanted to work with further. While I am sure it could have worked, I am more the type of person to overbuild something so I KNOW it will work, even in non-optimal conditions. I ended up with a homebrew controller, fairly cheap, can easily handle clusters, and it works way better than an Electron Beam even for single engine launches:

https://www.rocketryforum.com/showthread.php?s=&threadid=16641

If you want to go one step further, I would really reccomend the DIY approach. My controller was fun to design and put together, and very satisfying to use.
I've had a DIY controller in the back of my mind for a long time, and I've followed various threads about your controller and others that people have built. It would be fun and rewarding, I'm sure; I just do not have the time to do it.

After reading a bunch of other threads yesterday, I might end up just adding an external power connector (clips?) to the Electron Beam, and using a pair of rechargeable 7.2 V batteries as the source. I see them for sale at Wal-Mart all the time when I go there to buy motors.

So I'm still mulling things over a bit, but I have GOT to have something ready by Memorial Day weekend so I can test-fly my 2-motor cluster rocket, as discussed in the thread linked below. I'm planning to fly it at a Cub Scout rocket launch on June 4th, so I've got to have some reliable way to ignite both motors.

https://www.rocketryforum.com/showthread.php?s=&threadid=16276
 

grimlock3000

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It would be fun and rewarding, I'm sure; I just do not have the time to do it.
It does not take that long at all when you get the right parts. I could probably do another one of these in less than an hour, and that includes waiting for some of the epoxy to set.

Anyway, when you get a power source, check out cheap motorcycle batteries as well. It might be cheaper to just get a cycle battery to use as a power source instead of two 7.2v batteries. Also, I believe you will want to replace the continuity bulb in the Electron Bean with a 12v bulb, however I forgot the specifics of this.
 

JRThro

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Originally posted by grimlock3000
It does not take that long at all when you get the right parts. I could probably do another one of these in less than an hour, and that includes waiting for some of the epoxy to set.

Anyway, when you get a power source, check out cheap motorcycle batteries as well. It might be cheaper to just get a cycle battery to use as a power source instead of two 7.2v batteries. Also, I believe you will want to replace the continuity bulb in the Electron Beam with a 12v bulb, however I forgot the specifics of this.
You're right, I will need to replace the bulb.
 
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