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E Model Rocket Launch Controller

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tfrielin

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I'm getting into for the first time launching F-15-6 engines and F-26-6FJ engines (for Estes Mammoth Nike Smoke respectively). So, is the Estes E Model launch controller sufficient to ignite each of these engines?
 

samb

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Yes for the F15 (black powder) and maybe (not) for the F26 (APCP). The composite motors are more reliably ignited with a 12V controller, however you can light one with the Estes E controller by sittin' on the launch button, prayin' to the rocket gods, and using fresh alkalines (and lotsa spares). Do you already have an E controller ? The best controller Estes currently sells is the PSII with 6 C alkalines or LIPO battery power.

estes psii controller.jpg

https://www.estesrockets.com/002240-pro-series-iitm-launch-controller
 

ThirstyBarbarian

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I agree with what samb said above. The igniters (or "starters") for F15 motors are exactly the same as for other black powder motors, so ANY Estes controller will actually light the igniter --- it's just that some don't have long enough wires for a safe distance, so they sell E Controllers and Pro Series controllers with longer wires.

If you are going to use Estes brand igniters for your composite motors, then their controllers will work, because even their igniters for composite motors can be lit with less than 12 volts. If you are going to use other brands of igniters, such as Aerotech First Fire (and you probably will), then you will need a 12-volt controller.
 

Scott_650

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Anyone have a good LiPo battery source for the PSII controller? Mine has worked great with alkaline batteries for BP motors but I'm supposing a better battery will be a good thing for composite motors.
 

Woody's Workshop

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I have one of these. I was going to put a lipo battery in it. But after contacting several hobby suppliers none could offer up a battery that would work.
They all tried to contact Estes for what they had in mind, even though I sent the specs from the instructions.
I ordered a pair of JST plugs with both ends (only way I could get them) with 6" wires for $2.39 They came in the mail today.
I'm going to use a 6' extension cord and cut the ends off. Solder the JST plug on one end that fits the plug in the controller.
I will use a slide on connector that fits a 12v, rechargeable battery.
I'll keep it all in an old plastic tool box with with all 3 sizes of launch pads.
Should be able to launch just about anything with that set up.
The battery is $15 bucks shipped, the controller I got a couple years ago in the bonus xmas gifts box I won.
All I've been using for years is 20' of 2 zip wire with a little round door bell button from the end with battery clips, and mini clips on the other end for igniters.
No safety key, no continuity light, just hook up, press and whoosh.
But I fly all by myself in a life long friends farm field.

Anyone interested in in the other pair send me a pm. I'll never have a use for them.
$1.50 shipped to the 48.

Yes for the F15 (black powder) and maybe (not) for the F26 (APCP). The composite motors are more reliably ignited with a 12V controller, however you can light one with the Estes E controller by sittin' on the launch button, prayin' to the rocket gods, and using fresh alkalines (and lotsa spares). Do you already have an E controller ? The best controller Estes currently sells is the PSII with 6 C alkalines or LIPO battery power.

View attachment 309490

https://www.estesrockets.com/002240-pro-series-iitm-launch-controller
 
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caveduck

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Time for a slight bit of engineering. Over in this thread https://www.rocketryforum.com/showthread.php?62122-Estes-Pro-Series-II-Launch-Controller it's reported that the PSII controller will put 3.17 amps through a dead short across the clips with 9.24V of alkaline cells. That implies a total internal resistance (batteries + circuit) of a bit less than 3 Ohms. The internal resistance of 6 brand-new C alkaline cells is about .75 Ohms, roughly doubling to something like 1.5 at 50% discharge. Assuming the test batteries were 50% discharged, we have about 1.5 ohms in the circuit itself, which seems reasonable.

This is where LiPo batteries win BIG - per cell internal resistance is on the order of 10 *milliohms*, a huge reduction over alkaline cells. Therefore a 2S LiPo at 7.4V will generate much more amperage than the 9V alkalines - about 4.9A, and a 3S at 11.1V should provide about 7.4A. That will give you a lot more margin with high current ignitors. Er, starters. You don't even need a very big LiPo pack - a 500 mAh 20C rated pack will source 10 Amps continuous, more than enough for a basic launch controller.
 

dhbarr

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A 25500 Lithium battery should be a drop-in replacement for a C. Not sure if 22V is where you want to be, but certainly plenty of juice available.
 

JumpJet

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There are many 3-cell lipo batteries out there that will work. Hobby King has many packs that will work. There are a lot more packs that will work if you use an JST adapter or change the plug to a JST connector.

Even a small 300mAh pack would work since you are only going to be drawing a couple amps from the pack for a short while. I've set off 8 igniters at a time using a similar size battery.


The attached image is a pack Tower Hobbies sales.

John Boren

3 cell lipo.jpg
 

TangoJuliet

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Do LiFe batteries provide similar stats as the LiPo?

I only ask because I understand the LiFe technology to be safer in terms of storage and charging according to some of my R/C buddies to know electrical things much better than I do. I've had some LiPo's in the past, but was very leary of them because I'm away from home quite often and I've seen evidence of fires due to improper charging or damaged packs, and I've been told that storage rates need to be closely monitored.
 

JumpJet

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All the LiFe Packs I know about are used for transmitter packs that are LOW current draw. I really don't know enough about them to give you a good answer.
I know a 7 or 8 cell 900 mAh MiNH battery would work but they are very hard to find these days. If you purchase a Lipo Charger you shouldn't have a problem with your Lipo Battery pack.


John Borenj
 

Scott_650

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My original alkaline C cells have lasted through a fair number of launch sessions over the last six months but, with the hopeful increase in launches after my upcoming retirement, probably worth buying a LiPo pack and charger.
 

caveduck

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LiFe cells main advantages are being more resistant to overheating and having a flatter voltage vs time curve. But in almost all other respects they are considerably inferior to LiPos, which explains why they aren't as common. Energy density is lower and current delivery is about 1/4 as much (typically 5C continuous / 10C burst), and they only produce about 3.3V per cell instead of 3.8+. The flatter voltage curve is a double edged blade as it makes charge level sensing less accurate. There's some nice test data with voltage curves here: https://rightbattery.com/lipo-liion-life-batteries/ They will work for a personal launch controller just fine though - a 3S will push over 6A across shorted clips, within the burst capacity of a 700 mAh or larger pack.
 
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JumpJet

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My original alkaline C cells have lasted through a fair number of launch sessions over the last six months but
You should get over 300 launches with a good set of Alkaline Batteries in this controller.


John Boren
 

dhbarr

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It shouldn't especially matter. The pad controller has very little idea of what's on the igniter.

ALTHOUGH: if you're approaching marginal and really smoosh-jam the launch button, you'll see a decline.

LiFeS2 is a great ( though pricey ) sub for Alky; YMMV.
 
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