More reliable - E9 or E12?

[J Blatz]

I have never had either pop.

What is the consensus on which motor (of current vintage) is more reliable?

 

[rstaff3]

I don't think my numbers may be that useful because most of the E9's were flown prior to the rampant reports began popping up. But here goes anyway.

Between 2002 and 2016, I flew 146 E9s and had one cato.

Since the E12s were released and 2016, I flew 31 and had 4 cato's.

 

[DeeRoc29]

I don't keep count, but I've been flying E9's for years and have never had a single failure.

Not flown an E12 yet so can't comment there.

 

[swatkat]

I'm 2 for ~50 on E9's
0 for 18 on E12's

 

[dpower]

The first batches of E12 (2011 date codes) I flew, had a high failure rate. Since then, they've been fine.

 

[tbonerocketeer]

My last Estes flight was 6 e9-8, 3 Catoed

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[Cabernut]

I've flown 3 E9s and several E12s, only cato I've had was a C11...

I've always had the impression that E9s were more prone due to the long burn time but I definitely could be wrong on that.

 

[shreadvector]

Let's examine that impression.

Do the motors that fail have the failure occur late in a long burn while they are moving very fast and at high altitude?

Of do they fail within a fraction of a second of ignition?

There is nothing scientific about this thread, it is mostly going to be posts from people who have had failures. There will be very few posts from the vast majority who have had zero failures.

And, of course, 99.67% of the tens of thousands of E9 and E12 motors were flown by people who have never heard of The Rocketry Forum, so there will be no input from them.

Finally, if the rumors that the E9 is discontinued in favor of the E12 are true, then you can stop worrying about the E9, and buy lots of E12 motors and test them out. If you still have any E9-6 or E9-8 motors, then use them in the upper stage of a model that uses an E12-0 (or and E16-0 or F15-0) for the booster.

I've flown 3 E9s and several E12s, only cato I've had was a C11...

I've always had the impression that E9s were more prone due to the long burn time but I definitely could be wrong on that.

 

[markkoelsch]

I have tried 4 e9 flights. 3 Catoed. I will never touch one again.


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[Nytrunner]

Haven't had an E9 pop on me.

Have witnessed several pop in other rockets, but those were from known bad date codes upon autopsy.

 

[Rocketjunkie]

All Estes motors cato occasionally. If the E9s and E12s are as reliable as D12s I'm happy. In my experience the E9s have been in the pipeline long enough for environmental factors to be evident and I see E9s to have the reliability. E12's and especially the 29 mm motors, I will wait a few more years to see what environmental variations will do to the cato rate. The old Rocketflite big BP motors were good when new, but deteriorated badly with age.

 

[EXPjawa]

I've only seen one E12 cato, but it still the only one I've tried to fly. I do have the remaining two from the package, but have been reluctant to use them. I've not had E9 failures, but have only used a few of them as well.

 

[Nytrunner]

Stick them in a frisbee and let em rip!

 

[MALBAR 70]

I've flown quite a few E9's and E12's and have only had two or three E 9 cato's.
Never had an E12 cato on me (knocks on wood).
The most destructive cato I've had came from a C 6-5. It completely destroyed an MPC Red Giant.

 

[bibbster]

Finally, if the rumors that the E9 is discontinued in favor of the E12 are true...

It's true. My local hobby shop had their distributor tell them that so I contacted Estes and they confirmed it.

 

[shreadvector]

"It's twue!...It's twue!!!"

It's true. My local hobby shop had their distributor tell them that so I contacted Estes and they confirmed it.

 

[tbonerocketeer]

It's true. My local hobby shop had their distributor tell them that so I contacted Estes and they confirmed it.

Based on other sites, the e16 and F15 are as well.

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[bibbster]

Lovely. So what does one who just got into the hobby and doesn't fully understand the motor designations do for engines for the rockets that specify these engines and no other options?

 

[shreadvector]

They ask Alexa.

Or they contact the manufacturer using their website listed in multiple places all over their product packaging, instructions, etc.

Lovely. So what does one who just got into the hobby and doesn't fully understand the motor designations do for engines for the rockets that specify these engines and no other options?

 

[bibbster]

Yeah, I guess I'd rather contact the manufacturer instead of asking on a forum where everyone has been helpful until 12:11pm today. :lol:

 

[Zeus-cat]

I have had one E9 CATO and I have flown 38 of them. I have had one D12 CATO and have flown 219 of them. The D12 failed instantly and was pretty spectacular. Beautiful white smoke against a brilliant blue sky and it made a heckuva bang when it blew. Too bad no one got a photo or video of it. The rocket was undamaged and flew 10 minutes later on a new motor.

 

[viciouspeanut]

Yeah, I guess I'd rather contact the manufacturer instead of asking on a forum where everyone has been helpful until 12:11pm today. :lol:

If the package only references an E9, an E12 would fly it just fine. E designates the total impulse (Newton Seconds), and 12 designates the newtons of average thrust. Multiply that by burn duration and you have the total impulse. Of course there is way more going on, such as initial thrust spikes, etc. Thrustcurve motor guide is a handy free online tool that can help you out a lot too.

 

[bibbster]

Thank you, Mr. Peanut, err...viciouspeanut. My concern comes from reading about using the wrong size engine and destroying the rocket because of it. My daughter won't be real excited if I destroy her rockets. :lol:

I'll check out Thrustcurve again and try to wrap my brain around what it going on with an engine as it ignites and shoots the rockets to the sky.

 

[rharshberger]

Yeah, I guess I'd rather contact the manufacturer instead of asking on a forum where everyone has been helpful until 12:11pm today. [emoji38]

We also use OpenRocket or Rocsim to determine motor choices and delay lengths😁

 

[bibbster]

Thank you, Rich. Do those programs have tutorials by chance?

 

[viciouspeanut]

Thank you, Mr. Peanut, err...viciouspeanut. My concern comes from reading about using the wrong size engine and destroying the rocket because of it. My daughter won't be real excited if I destroy her rockets. :lol:

I'll check out Thrustcurve again and try to wrap my brain around what it going on with an engine as it ignites and shoots the rockets to the sky.

Haha, I need a Mr Peanut avatar!

You are probably seeing people use people use fast burn composite motors in kits designed for black powder motors. Balsa fins (and just large flappy fins) aren't especially fond of that lol.

As for simulator tutorials I can't really recall, but I learned from just playing around with it. We have a few gurus here who might be able to assist on that too. Check out the motor profiles on thrustcurve and it'll really help you get a good idea of how the burn rate works out on these motors. Pretty cool stuff.

 

[tHoagland]

Thank you, Rich. Do those programs have tutorials by chance?

I'd suggest looking at the book Make:Rockets by Mike Westerfield. Not only does it have a short intro into simulating rockets with openRocket but is also has great descriptions of how model rockets work, choosing motors, and even designing your own rocket.

Tim

 

[shreadvector]

E9 motors are almost gone from the Estes website motor page. Only the E9-4 remains:
https://www.estesrockets.com/rockets/engines/e-engines

All of the 29mm E16 and F15 motors remain listed:
https://www.estesrockets.com/rockets/engines/e-and-f-29mm

The words "out of stock" mean exactly that. They do not mean "Discontinued".

If they sell faster than they can make them, they are out of stock.

I have a bunch of E9-4 packs, so maybe it's time to start burning them up in my Starburst:
https://www.locprecision.com/product/pk-28starburst/

I'm expecting zero catos.

 

[bibbster]

I'd suggest looking at the book Make:Rockets by Mike Westerfield. Not only does it have a short intro into simulating rockets with openRocket but is also has great descriptions of how model rockets work, choosing motors, and even designing your own rocket.

Tim

Thanks, Tim, I'll see if I can pick up a copy somewhere.

EDIT: I happened to recently receive a $5 coupon for Google Play ebooks that I almost forgot about. I just downloaded the book for $5.46. Thanks again, Tim!

 

[tHoagland]

Glad it's worked out. How do you like the book in electronic form? I buy most of my novels as ebooks for a paperwhite kindle but given the excessive (in a good way) number of photos in this book, I bought the hard copy but am not opposed to owning it both ways..

I'd also note that Mike Westerfield also authored "Make:High Power Rockets". Another well written book that you may be interested in exploring in the future