Aerotech G78-4 Mojave Green Single Use problem

[Philip Tiberius D.]

Anyone have a problem with the Mojave Green G78 single use “deploying” about 150ft after launch? Batch # 030519... Lost my North Coast Rocketry Hobgoblin (Fire) and set a bit of pasture on fire as well. Motor sputtered a great deal before and after ejection.
Regards
Philip

 

[tbonerocketeer]

Report it to aerotech

Anyone have a problem with the Mojave Green G78 single use “deploying” about 150ft after launch? Batch # 030519... Lost my North Coast Rocketry Hobgoblin (Fire) and set a bit of pasture on fire as well. Motor sputtered a great deal before and after ejection.
Regards
Philip

 

[swatkat]

I had that experience (CATO at 150 feet) with a G77R-4 just a short time ago. I don't recall what batch it was from.

 

[Philip Tiberius D.]

I had that experience (CATO at 150 feet) with a G77R-4 just a short time ago. I don't recall what batch it was from.

Do you remember if the motor “sputtered” a lot? Going to follow tbonerocketeer’s advice and send a note (and vid with pic) to Aerotech - driving to LDRS so might even see them there.

 

[Philip Tiberius D.]

Anyone have a problem with the Mojave Green G78 single use “deploying” about 150ft after launch? Batch # 030519... Lost my North Coast Rocketry Hobgoblin (Fire) and set a bit of pasture on fire as well. Motor sputtered a great deal before and after ejection.
Regards
Philip

Thanks you tbonerocketeer... will do

 

[Cameron Anderson]

Do you remember if the motor “sputtered” a lot? Going to follow tbonerocketeer’s advice and send a note (and vid with pic) to Aerotech - driving to LDRS so might even see them there.

I flew a G78 a year ago and it sputtered for a few seconds on the pad. Took two igniters to get it off the pad.

 

[swatkat]

nope, it lit OK. Here's the video. It just had the same behavior as yours at 168 feet... according to the altimeter.

and the aftermath...

 

[Philip Tiberius D.]

nope, it lit OK. Here's the video. It just had the same behavior as yours at 168 feet... according to the altimeter.

and the aftermath...View attachment 392175

Crap. That sucks. I have that rocket to build... did you contact AeroTech?

 

[swatkat]

Crap. That sucks. I have that rocket to build... did you contact AeroTech?

I did... motor was too old though. date code was 4 years old. I believe they are only good for one year on single use. I had purchased two of the same motor from our local dealer the prior flying season, but even then, it was 14 months since the date of purchase. Other Single Use motor went just fine later that year. Same date code.

 

[Cameron Anderson]

I did... motor was too old though. date code was 4 years old. I believe they are only good for one year on single use. I had purchased two of the same motor from our local dealer the prior flying season, but even then, it was 14 months since the date of purchase. Other Single Use motor went just fine later that year. Same date code.

4 years is nothing, AP is good for 3 times that. I routinely fly 5 year old reloads and have even flown one that was 11. Age didn't do this unless you stored it in a swamp.

 

[Steve Shannon]

From NFPA 1125: 7.9.2 If the expected shelf life of a rocket motor or motor- reloading kit is less than 10 years, the manufacturer shall imprint a “use before” date on the package or motor casing.

 

[Cameron Anderson]

From NFPA 1125: 7.9.2 If the expected shelf life of a rocket motor or motor- reloading kit is less than 10 years, the manufacturer shall imprint a “use before” date on the package or motor casing.

I'm sure that rule exists out an abundance of caution. There is zero chance a 4-year-old, commercially produced G motor CATOd due to its age. None.

 

[Arsenal78]

Age didn't cause the motor to cato, it was just a bad motor which can happen. Now if Aerotech refuses to uphold the motor warranty because of the age, that's a different story.

 

[nabooengineer]

Uggh. I had a G76-4G RMS cato right off the pad 24-Aug-2019, lot #03040903. It was 10 years old, and sealed in original bag, and always kept in hazmat locker with desiccant. It was a partial deploy within 80ms of ignition (had high speed cam running) and totally destroyed the MMT & recovery. Bird safely cored, and afterwards I did a root cause. Still have the liner, casing, nozzle. I filed it with motorcato.org that night. Some times it really is rocket science! BTW, early that day I launched some SU Fs & Gs, that were even older, no issue. I take it that sometimes it just happens... you get one that is just bad.

 

[MECO]

I had a G78-10 burn through the forward closure as soon as it came up to pressure. Incinerated my Madcow DX3 on it's first flight. Aerotech did send me 2 replacement motors.

 

[Steve Shannon]

I'm sure that rule exists out an abundance of caution. There is zero chance a 4-year-old, commercially produced G motor CATOd due to its age. None.

That’s my point. It’s expected that the shelf life would be at least 10 years.

 

[Cameron Anderson]

That’s my point. It’s expected that the shelf life would be at least 10 years.

Ah, I misunderstood. Apologies.

 

[swatkat]

4 years is nothing, AP is good for 3 times that. I routinely fly 5 year old reloads and have even flown one that was 11. Age didn't do this unless you stored it in a swamp.

Agreed, it's just in their Terms and Conditions. I bet half of our local vendor's product is more than 3-4 years old! I've launched without issue other single use motors from 2005, no issues. But when it comes to a claim...

 

[swatkat]

That’s my point. It’s expected that the shelf life would be at least 10 years.

Agreed, I've had zero issues with many older motors, heck my L2 motor was a "medium" delay J500G, that tells you how old it was. But warranty claims and terms are a different story. AT was really good about a case warranty though, also a stock out of the bag, fresh from Wildman reload, that was less than 6 months old Cato'd stock in a very similar way... also on video, embarrassing way to lose a drag race...

 

[Philip Tiberius D.]

I had a G78-10 burn through the forward closure as soon as it came up to pressure. Incinerated my Madcow DX3 on it's first flight. Aerotech did send me 2 replacement motors.
View attachment 392239
View attachment 392240

I'm pretty sure, judging from your photo and talking to others that this is what happened to mine. Did another flight last night (9-2-19) at my Rocket Pasture and am planning one this morning as soon as I get off here (Launch 0915) with another AeroTech. The baby Red Max (all fiberglass) is a great (rugged) test rocket.

 

[JohnCoker]

Please continue to report motor failures:
https://motorcato.org/

(We'll be pushing a new site *soon* that will let everyone view the reports, but for now it's still important to collect the data.)