Anatomy of an E9 CATO

This CATO happened at a club launch in January. Just now getting a chance to share the photos. I pulled these images from a video I took of the launch. Motor was an Estes E9-4. No injures; moderate damage to motor mount. MESS report submitted. The mushroom cloud is my favorite image.

The motor...

Nice fireworks show.

So what are your suspicions as to the cause of failure? Nozzle? Cracks in the grain? I agree: the mushroom cloud is impressive...

Because of things like this, I'm very hesitant to put any BP motor past a D-12 in any of my (or my kids') rockets. Glad no one was hurt and the rocket can be repaired...



Later!

--Coop

Coop said:

So what are your suspicions as to the cause of failure? Nozzle? Cracks in the grain? I agree: the mushroom cloud is impressive...

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I'm really not sure. I keep all my motors in the house to avoid temperature cycling. It was cold the day of the launch (low/mid 40) but the motor wasn't outside that long before we launched it. I do a quick visual on all motors and nothing looked out of the ordinary. As you can see from the last photo both the nozzle and plug blew out. As a precaution I destroyed the rest of the package with this lot code.

Date code?

06 14 01
A

June 14, 1901. There's the problem.

Vern must have made this one on Mabel I...

Trooper said:

June 14, 1901. There's the problem.

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It looks like the bond between the casing and the propellant grain failed on ignition. Due to the increased surface area, the motor overpressurized and blew out the nozzle and set off the BP charge.

The motor was 13 1/2 years old. I only saw 1 reported E9 failure from that lot in 2013, and it was a delay failure. You probably just experienced a random statistical failure. You should report the failure (and attach a photo) to Estes if you haven't done it already. I'm sure they'll take care of you.

Bob

cerving said:

Vern must have made this one on Mabel I...

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In kindergarten.

I don't like to hear this. I just re-built my Double Shuttle for the 3rd time after two E12 cato launches. I figured that I would go back to E9's, which are reliable(?). Thanks for the lot number. I need to check my inventory.

I don't think there's an issue the 2001 E9 lot.

There were 15 E9s failures from lot 06 28 11 and 9 E9s failures from lot 8 18 11 reported out of the 40 reported E9 failures in 2013 . You should understand however that in a single 8 hours shift, Estes makes about 5,000 motors. That's 1 in 300 and 1 in 500 respectively if the lot number was only used for one day which I believe is incorrect and an underestimate of the motors produced with that lot number.

Over the same time period, 43 E12 failures were reported from lot 8 18 11 out of the 50 reported E12 failures in 2013. That's about 1 out of 116 occurrence if the lot only consisted of 1 days run which is probably incorrect.

I would guess that 80-90% of the rocket launches in 2013 involved Estes engines, so these failure, which are disastrous if they happen to you, are really not common occurrences.

Bob

I had my first E12 failure (after many successes) a couple of weeks ago. It was from the 8 18 11 batch as well (as have my successes, generally). It failed much like the E9 in the OP, but before the rocket (my QCC Explorer) ever left the pad. The motor mount was blown out on the ground below the pad and the upper section - from the top plate of the Semroc baffle through the nose cone - was blown 20 feet or so in the air on a fireball and landed nearby. The rest of the baffle was not found.

It's been reported to Estes, MESS report filed, and replacements are on their way.

I have a number of E9s with that date code as well....and now I'm a little more reticent about using them.....

added: The QCC is ready to fly again. I was able to put new centering rings on the motor mount and install it from the top, and assemble another EB-60 baffle from stock on hand. Mine is modded so that the upper portion is a payload section rather than just a continuation of the BT, so it wasn't that far to push the rebuilt motor mount in from the other end.

further added: after looking at the OP's pictures, I'm thinking his E9 and my E12 failures occurred at the same launch - the January WAC launch at Sixty Acres in Redmond, WA.....

Great shots. Sorry form your loss. Did you at least get a full chute deployment?

bobkrech said:

I don't think there's an issue the 2001 E9 lot.

There were 15 E9s failures from lot 06 28 11 and 9 E9s failures from lot 8 18 11 reported out of the 40 reported E9 failures in 2013 . You should understand however that in a single 8 hours shift, Estes makes about 5,000 motors. That's 1 in 300 and 1 in 500 respectively if the lot number was only used for one day which I believe is incorrect and an underestimate of the motors produced with that lot number.
Bob

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That failure statistic assumes every motor produced has flown. I am not sure how to account for all the motors in the supply chain (store inventories, warehouses, flyer's stashes, etc) but I do know that our small club has seen about 5 E9 CATOs in the last couple years, similar to the OP. Being generous, I would guess at total of about 50 E9s have been flown by our club. That is 1 in 10 failure rate, which is pretty high, to me. I know I am wary of using one now in a "nice" rocket.

Yes, MESS reports have been submitted (at least the flyers told me they did), and yes, Estes was alerted.

I've seen many many E9 & E12 launches over the years... Yes.. I have seen numerous failures too.. but no more than any other motors. I personally have only experienced one E9 cato back when they first came out. From talking to those in the "know" as they say, it isn't so much of the heat cycling as much as launching them in the cold. I think it was something like 70 degrees lower than the highest temp they have been stored in... so.. its not to hard to assume that most motors have seen upwards of 120 deg in a UPS truck or warehouse so maybe you shouldn't launch them below 50 deg??

Jerome

bobkrech said:

You should report the failure (and attach a photo) to Estes if you haven't done it already. I'm sure they'll take care of you.

Bob

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Sent report and pictures to Estes a little over 2 weeks ago. No response.

BEC said:

... replacements are on their way.

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You must know somebody at Estes.

Bat-mite said:

Did you at least get a full chute deployment?

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No but I did get a charred chute.

bobkrech said:

I don't think there's an issue the 2001 E9 lot.

Bob

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As an aside, these were purchased within the past 12-18 months.

I had an E9 CATO last summer. It was a new purchase, and (as far as I know) it never experienced cold weather. Just blew up on the pad, and tried to take my Big Daddy with it.

sl98 said:

Sent report and pictures to Estes a little over 2 weeks ago. No response. You must know somebody at Estes........As an aside, these were purchased within the past 12-18 months.

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No trying to make excuses for not answering their e-mails, but you should realize that over 95% of e-mail traffic at most businesses are spam, so most use a spam filter. I have no idea what Estes uses but it's possible yours got trapped or Estes is way behind in reading their e-mails. I suggest you call Estes customer service during business hours. They answer their phones.

Bob

Estes had a mail sever problem a couple of weeks ago and they did not get any e-mail for approxiamtely a week. it should be working now.

I sent an e-mail on Sunday and did not hear back, so i may follow up with a phone call. It was not related to a motor failure.

A flyer at our launch on Saturday had an E9 fail as it approached the top of the launch rod. This was much more typical of the D12 failure modes I described in my R&D report, where the flame front has either reached the sidewall or is just about to reach the sidewall but is able to reach it sooner than normal because of a small crack that develops around the outer nozzle/propellant interface. This crack actually lowers peak thrust because you get a smaller dome, but if the propellant to casing mechanical bond is compromised, then the flame front can propagate up the sides and you get a cato.

bobkrech said:

No trying to make excuses for not answering their e-mails, but you should realize that over 95% of e-mail traffic at most businesses are spam, so most use a spam filter. I have no idea what Estes uses but it's possible yours got trapped or Estes is way behind in reading their e-mails. I suggest you call Estes customer service during business hours. They answer their phones.

Bob

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rocketguy101 said:

That failure statistic assumes every motor produced has flown. I am not sure how to account for all the motors in the supply chain (store inventories, warehouses, flyer's stashes, etc) but I do know that our small club has seen about 5 E9 CATOs in the last couple years, similar to the OP. Being generous, I would guess at total of about 50 E9s have been flown by our club. That is 1 in 10 failure rate, which is pretty high, to me. I know I am wary of using one now in a "nice" rocket.

Yes, MESS reports have been submitted (at least the flyers told me they did), and yes, Estes was alerted.

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Let me explain what data we obtain and how I analyze it.

The only way S&T collects MESS data is when and if a motor failure is reported to S&T via the NAR website and since last year motorcato.org

In 2013, S&T received 194 MESS reports from the NAR and motorcato websites. Of these 124 were on Estes BP motors. Of these 50 were E12s and 40 were E9s.

43 of the 50 E12s came from the 8 18 11 production lot. Of the other 7, 4 came from 3 different lots, and the lot of the remaining 3 was not identified.

My analysis of the reported E12 failures indicates that there were statistically more failures from the 8 18 11 lot than any others.

Of the 40 reported E9 failures, 15 came from lot 6 28 11 and 9 came from lot 8 18 11. Of the other failures not more than two came from any single lot.

My analysis of the reported E9 failures indicate that there were statistically more failures from the 6 28 11 and 8 18 11 lots than any others.

I have personally witnessed both E9 and E12 failures and in several cases, more than 1 motor from the same package failed which leads me to believe that it you could likely have several bad motors in a row so it is possible to have 2 or 3 bad motors in a pack. If you buy your motors from a single vendor, it's possible that their wholesale order had a bunch of bad motors that were not detected by Estes QC which entails static firing of ~3% of the motors coming off the production line. I'll speculate that is the case in your observations. I know this was what I observed.

Aside from those 2 lot numbers, I just have not seen any trend on motor failure that raise any flags. I've also seen a number of good flight with E motors from 8 18 11 and 6 28 11 motor lots, so it's hard to make any more claims than what I have reported.

We just don't have sufficient data to draw any further conclusions.

Bob

Is'nt that what Estes E Motors are supposed to do?

TopRamen said:

Is'nt that what Estes E Motors are supposed to do?

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This seems to be your standard response.... it doesn't do anybody any good by being so negative. It was somewhat amusing the "first time"... ya.. the "first time"

You have stated that you have never launched one of these motors, nor seen one launch in person. You might want to reserve your comment until you have some actual experience in the matter. These motors are quite fun to launch. Nice smoke and sound. I agree with another TRF poster with whom I launch with. He has speculated that we hear more about E9 & E12 failures because they are just more noticeable. I have seen far more little 18mm BP motors go pop.. but nobody seems to care much.

JeromeK99 said:

This seems to be your standard response.... it doesn't do anybody any good by being so negative. It was somewhat amusing the "first time"... ya.. the "first time"

You have stated that you have never launched one of these motors, nor seen one launch in person. You might want to reserve your comment until you have some actual experience in the matter. These motors are quite fun to launch. Nice smoke and sound. I agree with another TRF poster with whom I launch with. He has speculated that we hear more about E9 & E12 failures because they are just more noticeable. I have seen far more little 18mm BP motors go pop.. but nobody seems to care much.

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Ok, valid Points all. Did'nt mean to pee in your Coolaid. Eventually, I will try them. Last year as a matter of fact I began a Build specifically for E Motors.
I'll refrain from making Comments about them from now on since it bothers you.

Sorry... I did come off a bit cranky...

I just hate to see comments like that with no real basis. It will effect how others perceive a product before actually seeing them in action. The Estes E series BP motors are quite spectacular and available to any rocketeer.

Jerome

JeromeK99 said:

Sorry... I did come off a bit cranky...

I just hate to see comments like that with no real basis. It will effect how others perceive a product before actually seeing them in action. The Estes E series BP motors are quite spectacular and available to any rocketeer.

Jerome

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Don't worry, I took it in Good Jest.