First G-80 - exploded

[CCollins]

First time trying to shoot a G series motor didn't end so well. Previous shot with an F had gone flawlessly. Both shots were with the Aerotech Estes branded motor. First was an F-26. Second was the one that exploded, it was a G-80. The only difference was that the second one was shot with an Estes Sonic igniter - the first had a Aerotech First Fire Jr. Motor did not "ignite" - it still has a large amount of propellant in it from just feeling the weight. When it exploded, it blew the side off of the motor case, split the motor mount and blew out a huge chunk of the side of the rocket as well. Sent that chunk flying over us - you can see it in the video. No idea what happened but it was a bit scary. I kept the igniter and motor. Think I would have any luck with Estes customer service getting a replacement? From what I have read, sounds like I will be sticking with First Fire Jr. or Copperhead igniters from now on although I can't be sure it was solely the igniter's fault. Igniter was inserted fully to the top of the motor and taped in place prior to setting it on the pad. Too bad really, rocket looked fantastic and had flown like a champ earlier in the evening. Also flew a Mega Der Red Max on an F-50 that went great. Loved this Argent - was really looking forward to a big flight. Conditions were perfect too. Ugh. Might be repairable - might not. I'll have to gather myself and go carefully survey the damage later. Any ideas?

https://www.dropbox.com/s/28b2arufyz62m0f/VIDEO0010.mp4

-CC

 

[blackbrandt]

Hi and welcome to the forum!

Some things that you will want to know.

That motor failing like that is called a motor CATO (Motor catastrophe at takeoff).


That can be caused by several things:

A crack in the propellant grain can allow more propellant to burn at once than the casing was designed to handle since more propellant surface area is exposed. This is common in black powder motors that have been dropped.


A small chunk of propellant can fall into the nozzle and block it which can cause a pressure buildup and an explosion.



There may be a defect in the casing, nozzle, propellant, binding of the propellant to the casing, or any of a combination of these.

Also, was the motor resting on the blast deflector, or was it off? If it was resting on the blast deflector, you have most likely had the motor overpressurize, and then blow the case.




Posting a picture of the motor will allow us to tell you what happened. Estes, although I have not had experience with them, is apparently decent at getting a replacement motor. If you file a MESS report, it also helps.



Once again, pictures will help us.



Welcome to the forum!!

 

[bandman444]

Hi and welcome to the forum!

Some things that you will want to know.

That motor failing like that is called a motor CATO (Motor catastrophe at takeoff).

That can be caused by several things:

A crack in the propellant grain can allow more propellant to burn at once than the casing was designed to handle since more propellant surface area is exposed. This is common in black powder motors that have been dropped.

A small chunk of propellant can fall into the nozzle and block it which can cause a pressure buildup and an explosion.

There may be a defect in the casing, nozzle, propellant, binding of the propellant to the casing, or any of a combination of these.

Also, was the motor resting on the blast deflector, or was it off? If it was resting on the blast deflector, you have most likely had the motor overpressurize, and then blow the case.

Posting a picture of the motor will allow us to tell you what happened. Estes, although I have not had experience with them, is apparently decent at getting a replacement motor. If you file a MESS report, it also helps.

Once again, pictures will help us.

Welcome to the forum!!

Wow! Way to go BB. That was a fantastic response!

CCollins. Welcome to the forum. The only thing I will add, BB hinted toward it, is contact Estes. I have heard good stories about them replacing motors and even some damaged kits.

Good luck.

 

[Yoehahn]

Hi and welcome to the forum!

Some things that you will want to know.

That motor failing like that is called a motor CATO (Motor catastrophe at takeoff).

That can be caused by several things:

A crack in the propellant grain can allow more propellant to burn at once than the casing was designed to handle since more propellant surface area is exposed. This is common in black powder motors that have been dropped.

A small chunk of propellant can fall into the nozzle and block it which can cause a pressure buildup and an explosion.

There may be a defect in the casing, nozzle, propellant, binding of the propellant to the casing, or any of a combination of these.

Also, was the motor resting on the blast deflector, or was it off? If it was resting on the blast deflector, you have most likely had the motor overpressurize, and then blow the case.

Posting a picture of the motor will allow us to tell you what happened. Estes, although I have not had experience with them, is apparently decent at getting a replacement motor. If you file a MESS report, it also helps.

Once again, pictures will help us.

Welcome to the forum!!

-sniff- they grow up so fast :')
Great answer BB

 

[rcktnut]

When I became a bar, I flew a couple hundred or so of single use Aerotech motors during the first 7-8 years back into the hobby and only had 2 that blew out the nozzels at pressure up. No damage to the rockets, fuel grains still intact. I think the problem now is that they are either using inferior casings, or the casings are on the threshold of the pressures they can withstand. Seems to be alot of rockets getting blown up. The casings are splitting, rather than the nozzels being blow out.

 

[Rex R]

I've been told that it is normal for the propellant to self extinguish when the internal pressure drops that rapidly. you'll want (if possible) at least one picture of the failed motor showing the lot number, and one showing the area that ruptured (if they are not one and the same). Estes has been very good at replacing motors and kits. I'd visit their website (say on Tuesday) and use their webform to report the 'catastrophic motor failure' as well as filing a Mess report with NAR.
rex

 

[DizWolf]

I'd give the webform a shot first, but there have been issues with it not reporting to Estes properly at times.... If you don't get a reply in a few days I'm sure people here (myself included) have some direct email addresses in their email histories from prior claims. Customer Service once you actually get someone is superb.

Seems like an oddly long delay from countdown to CATO. In my experience Blue Thunder motors take off pretty quickly.

Depending on how it blew out the side of the rocket, it may or may not be an easy fix. Did the fins sustain any damage/ how do the CR's look?

 

[gdjsky01]

Estes wil take care of you. Try the form. If no answer in a day or two, try again. They sometimes take twice to get a hold of. Or PM mem and I have an address that worked (if the form does not).

Estes always replaced the motor(s) and the rocket.

 

[marcusSRG]

When I became a bar, I flew a couple hundred or so of single use Aerotech motors during the first 7-8 years back into the hobby and only had 2 that blew out the nozzels at pressure up. No damage to the rockets, fuel grains still intact. I think the problem now is that they are either using inferior casings, or the casings are on the threshold of the pressures they can withstand. Seems to be alot of rockets getting blown up. The casings are splitting, rather than the nozzels being blow out.

I bet you're noticing more casing ruptures than blown nozzles because the new AT SU motors have a fully molded case, including the nozzle. With this change of design it would seem more likely for the casing to rupture rather than blow out the nozzle in the rare case of a failure. The old SU motors had their nozzles epoxied in...I would think these would be more likely to blow the nozzle in a failure.

 

[CCollins]

Here are some shots of the damage. Thanks for the input. I will look into the Mess report and contact Estes Customer Service.

 

[gdjsky01]

Also we now have the forums to spread the information. Not that the net is NEW but now almost EVERYONE uses it. So we find out about more cases.

 

[DizWolf]

View attachment 124075

I bet that'd fly fine just as is. Looks like it was built solid.

To fix, I would soak some paper or a short cut of random tubing in glue or epoxy to patch the MMT.... then glue and fill the BT chunk if it still fits.

 

[rcktnut]

I bet you're noticing more casing ruptures than blown nozzles because the new AT SU motors have a fully molded case, including the nozzle. With this change of design it would seem more likely for the casing to rupture rather than blow out the nozzle in the rare case of a failure. The old SU motors had their nozzles epoxied in...I would think these would be more likely to blow the nozzle in a failure.

OK, I see, I haven't bought any SU in a long time. A guy in our club just recently got back into the hobby, and he has launched a bunch of the Estes F's & G's without any problems. Never seen the new ones up close, did not know they are one peice molded.

 

[bobkrech]

First time trying to shoot a G series motor didn't end so well. Previous shot with an F had gone flawlessly. Both shots were with the Aerotech Estes branded motor. First was an F-26. Second was the one that exploded, it was a G-80. The only difference was that the second one was shot with an Estes Sonic igniter - the first had a Aerotech First Fire Jr. Motor did not "ignite" - it still has a large amount of propellant in it from just feeling the weight. When it exploded, it blew the side off of the motor case, split the motor mount and blew out a huge chunk of the side of the rocket as well. Sent that chunk flying over us - you can see it in the video. No idea what happened but it was a bit scary. I kept the igniter and motor. Think I would have any luck with Estes customer service getting a replacement? From what I have read, sounds like I will be sticking with First Fire Jr. or Copperhead igniters from now on although I can't be sure it was solely the igniter's fault. Igniter was inserted fully to the top of the motor and taped in place prior to setting it on the pad. Too bad really, rocket looked fantastic and had flown like a champ earlier in the evening. Also flew a Mega Der Red Max on an F-50 that went great. Loved this Argent - was really looking forward to a big flight. Conditions were perfect too. Ugh. Might be repairable - might not. I'll have to gather myself and go carefully survey the damage later. Any ideas?

https://www.dropbox.com/s/28b2arufyz62m0f/VIDEO0010.mp4

-CC

Please fill in a MESS report at https://www.nar.org/NARmessform.html

and also send your photos and report the failure to Estes customer service with the motor date code for a warantee claim.

(Sorry - I didn't read the beginning of the thread. While Aerotech makes the motor, they are relabeled for Estes and Estes warantees it.)

Bob

 

[eggplant]

Hi, welcome to the forum!

Sorry about the motor issue! I have never had this happen to me, but the advice that you received sounds fine! Just one little thing, we don't "shoot" rockets, we fly or launch them.

I hope that your next flight goes better!

 

[shreadvector]

From the label, it was an Estes branded G80 motor, so even though Aerotech manufactured it for Estes, it would be Estes that handles the warranty claim for the motor and rocket.

As for some earlier comments about the cause of catos (not from Bob)....here is come clarification and correction:

Balck powder motors will not get a cracked grain from dropping them. This has been proven by scientific experiment and reported by several people in their NAR R&D reports (including me). You would need to hit the motor with a hammer very, very hard to get the grain to crack.

Composite propellant motors can indeed fail at ignition from a few causes such as a clogged nozzle (propbably not the case with the reported igniter for this particular motor) or a bubble in the propellant resulting in a huge increase in burning surface area or a defect in the casing. Now, the casing defect could be the result of mishandling (gripping with big channel-lock plyers so tight it creates a crack in the casing), but I am not sure if dropping thse casings would affect them. I would ask Aerotech if they did studies of the effects of dropping and rough handling. I would bet they did, but I have no real information - hence the "ask Aerotech" suggestion.

Composite motors are more likely than black powder motors to have a cato later in flight as the burning propellant surface can reach a bubble at any time in the burn. Also, an improperly assembled RMS motor could experience an o-ring burn through later in burn (but usually does so right after ignition). And if a chunk of the internal liner breaks free it could block the nozzle and lead to a cato and this usually occurs closer to the end of motor burn as more of the liner is exposed inside the motor.

See the cato document linked below for other info.

Please fill in a MESS report at https://www.nar.org/NARmessform.html

and also send your photos and report to Aerotech with the motor date code for a warantee claim.

Bob

 

[DizWolf]

Also we now have the forums to spread the information. Not that the net is NEW but now almost EVERYONE uses it. So we find out about more cases.

This is true, however there seem to be more reports of Estes motors blowing up than Aerotech. I'm not sure if it's actually the case or not. But if it is, it'd be worth looking at why.

 

[shreadvector]

This is true, however there seem to be more reports of Estes motors blowing up than Aerotech. I'm not sure if it's actually the case or not. But if it is, it'd be worth looking at why.

Because there have been X times more Estes G80 motors sold and fired compared to Aerotech?u

 

[Davidtmp]

This kind of worries me about the new HP single use motors. I'd hope they don't have issues as the rockets that will be damaged are going to be more expensive and not an Estes or Aerotech kit.
As far as the OP, since you had an Estes kit and motor, I'd be willing to bet you'll get a new kit and probably another motor out of them. They do take care of us. Tell Christine we all said Hi and Love Her!!

 

[shreadvector]

Single use new Aerotech motors are very very different construction than the G80.

This kind of worries me about the new HP single use motors. I'd hope they don't have issues as the rockets that will be damaged are going to be more expensive and not an Estes or Aerotech kit.
As far as the OP, since you had an Estes kit and motor, I'd be willing to bet you'll get a new kit and probably another motor out of them. They do take care of us. Tell Christine we all said Hi and Love Her!!

 

[DizWolf]

Because there have been X times more Estes G80 motors sold and fired compared to Aerotech?u

Wait, More estes Pro Series G80-7's sold and fired than AeroTech G80-7's? Really? And the CATO's seem to go across the board on the new Estes motors. I find it hard to believe there have been more made and fired than Aerotech branded motors.

 

[cerving]

Maybe not historically, but I bet it's true NOW. With 40% off at HL, I would be hard pressed to think of a reason to buy an Aerotech-branded motor instead of the Estes ones. I haven't had any problems with the Estes G80's that I've bought (other than the stupid 6V Estes Pro igniters fizzling out on 12V).

Wait, More estes Pro Series G80-7's sold and fired than AeroTech G80-7's? Really? And the CATO's seem to go across the board on the new Estes motors. I find it hard to believe there have been more made and fired than Aerotech branded motors.

 

[bobkrech]

From the label, it was an Estes branded G80 motor, so even though Aerotech manufactured it for Estes, it would be Estes that handles the warranty claim for the motor and rocket.

As for some earlier comments about the cause of catos (not from Bob)....here is come clarification and correction:

Balck powder motors will not get a cracked grain from dropping them. This has been proven by scientific experiment and reported by several people in their NAR R&D reports (including me). You would need to hit the motor with a hammer very, very hard to get the grain to crack.

Composite propellant motors can indeed fail at ignition from a few causes such as a clogged nozzle (propbably not the case with the reported igniter for this particular motor) or a bubble in the propellant resulting in a huge increase in burning surface area or a defect in the casing. Now, the casing defect could be the result of mishandling (gripping with big channel-lock plyers so tight it creates a crack in the casing), but I am not sure if dropping thse casings would affect them. I would ask Aerotech if they did studies of the effects of dropping and rough handling. I would bet they did, but I have no real information - hence the "ask Aerotech" suggestion.

Composite motors are more likely than black powder motors to have a cato later in flight as the burning propellant surface can reach a bubble at any time in the burn. Also, an improperly assembled RMS motor could experience an o-ring burn through later in burn (but usually does so right after ignition). And if a chunk of the internal liner breaks free it could block the nozzle and lead to a cato and this usually occurs closer to the end of motor burn as more of the liner is exposed inside the motor.

See the cato document linked below for other info.

Thanks Fred, my made. Correct my post. Didn't read the whole thread and assumed it was labeled as AT.

Bob

 

[CCollins]

Update: Report filed with Estes Customer Service. They responded today - they will be replacing and the Argent and the G-80. Wow! I am pretty impressed - don't see that kind of thing often today but way to go Estes!!!

MESS Report filed as well.

I am repairing the old Argent now and am about ready for prime/paint. Might get to that this weekend. I very much appreciate the advice you folks have provided. Thank you all very much!

Curtis

 

[marcusSRG]

Update: Report filed with Estes Customer Service. They responded today - they will be replacing and the Argent and the G-80. Wow! I am pretty impressed - don't see that kind of thing often today but way to go Estes!!!

MESS Report filed as well.

I am repairing the old Argent now and am about ready for prime/paint. Might get to that this weekend. I very much appreciate the advice you folks have provided. Thank you all very much!

Curtis

Estes will always take care of you! And don't let that scare you away from flying the G80T...it's a killer motor, especially since they uprated it. It has a nice visible blue flame now too. Use your new Argent for a special project...dual deployment or something!

 

[awseiger]

And get your hands on a G40! IMHO, an even more killer motor!

Glad to see everything is OK. I hate when CATOs happen....

 

[shreadvector]

The G40 is impressive because of the White Lightning propellant, but the G80 has a LOT more total impulse.

And get your hands on a G40! IMHO, an even more killer motor!

Glad to see everything is OK. I hate when catos happen....

 

[cerving]

The first time I flew a G80 was in a Leviathan, even in a big rocket like that it's an "Oh Wow!". Like somebody else said, it's a gateway drug to HPR... L1 is just a small step away, especially now that Aerotech has an H135 SU. A G40 is a nice motor, but it's really only a small step above a 24mm F32 SU.