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In an effort to be constructive ... the AeroTech warranty statement is silent on the industry practice of replacing motor hardware damaged by a defective reload. So Charlie is not "to blame" as you put it. Ideally AT should update the RMS™ Reload Kits section of the warranty statement to clarify what AT will do when a defective reload, under warranty, damages any case authorized for use (e.g. Dr Rocket, CTI cross loads, etc…).



As an Aerotech vendor, I have found their warranties to be very good. I have extra hardware and reloads to give out on the few times a warranty claim is in order. They have always sent me replacements with my next orders. Even though a good percentage of the time... the reload itself was not the problem... the assembly of the reload was. An O-ring assembled in wrong spot. Delay spacer installed on the charge well end, instead of the fuel grain end. Forward seal disk not properly seated in liner. Grains not bonded to the liner - needed on some reloads. Grain ends not fully glued/inhibited on larger moon burners. There has been a couple reloads that had cracked phenolic liners... these were discovered during the 'inspection' phase of the assembly. I replaced the liner then... both times. They both were successful flights. I'm pretty sure one was chipped during deburring the ends. This is why I check the grain fit first and only debur if needed. Have never needed to do so, and recommend caution.

Rick
Treasure Valley Rocketry
 
I had the last J99 cato Aerotech replaced the casing but wouldn't replace the reload. They had me choose an equal value in other motors. The cato ejected the forward closure. I glued in the forward closure and flew the other J99 I had. It worked Glad to see it coming back :)
 
Forgive me if this is answered elsewhere, but is it legal (ie within manufacturer's instructions and therefore not a research motor) to remove the BP ejection charge from a Q Jet motor? I have a saucer that I like to fly on Q Jets but the shortest delay is still long enough that it has landed by the time the ejection charge goes. I would much rather peel back the red caps, dump the charges into my BP can, and not risk starting a fire on the ground.

Thanks!
 
I have been known to remove part of the BP from a Q-Jet (especially the early ones that had KILLER ejection charges). It certainly makes sense to do as you suggest.

I know that doesn’t exactly answer your question. If I were the LCO or RSO at the launch I’d certainly be OK with it as I think doing what you suggest for the reason you suggest it outweighs technically “modifying” the motor.
 
I'd like to know why there are no more G80-4's. Indeed, any SU G80. Are the G79,78,77's just as good?
 
I'd like to know why there are no more G80-4's. Indeed, any SU G80. Are the G79,78,77's just as good?

I don't believe the G80's are discontinued, they are now considered DMS all with 14 sec. adjustable delays. They used to be in the Hobbyline category with the various delays. The G80's have a considerably higher total impulse than the others you listed.
 
Forgive me if this is answered elsewhere, but is it legal (ie within manufacturer's instructions and therefore not a research motor) to remove the BP ejection charge from a Q Jet motor? I have a saucer that I like to fly on Q Jets but the shortest delay is still long enough that it has landed by the time the ejection charge goes. I would much rather peel back the red caps, dump the charges into my BP can, and not risk starting a fire on the ground.

Thanks!

In my opinion there’s nothing wrong with that. One of the scariest fires I’ve seen was started by an ejection charge on the ground.
 
In my opinion there’s nothing wrong with that. One of the scariest fires I’ve seen was started by an ejection charge on the ground.
I routinely remove ejection charges from AT SU motors when using in saucers, pyramids, etc. Then put in a little super lube, and put the cap back on.
 
I'd like to know why there are no more G80-4's. Indeed, any SU G80. Are the G79,78,77's just as good?
I don't believe the G80's are discontinued, they are now considered DMS all with 14 sec. adjustable delays. They used to be in the Hobbyline category with the various delays. The G80's have a considerably higher total impulse than the others you listed.

They're available in 7, 10, and 13 second lengths, plus the DMS version
 
As an Aerotech vendor, I have found their warranties to be very good. I have extra hardware and reloads to give out on the few times a warranty claim is in order. They have always sent me replacements with my next orders. Even though a good percentage of the time... the reload itself was not the problem... the assembly of the reload was. An O-ring assembled in wrong spot. Delay spacer installed on the charge well end, instead of the fuel grain end. Forward seal disk not properly seated in liner. Grains not bonded to the liner - needed on some reloads. Grain ends not fully glued/inhibited on larger moon burners. There has been a couple reloads that had cracked phenolic liners... these were discovered during the 'inspection' phase of the assembly. I replaced the liner then... both times. They both were successful flights. I'm pretty sure one was chipped during deburring the ends. This is why I check the grain fit first and only debur if needed. Have never needed to do so, and recommend caution.

Rick
Treasure Valley Rocketry

That's good information to know! While I haven't flown enough MPR to experience a defect in my AT stuff, now that I'm jumping back into it with a new build, it is good to know somebody covers warranty issues when "user error" is not the problem!
 
That's good information to know! While I haven't flown enough MPR to experience a defect in my AT stuff, now that I'm jumping back into it with a new build, it is good to know somebody covers warranty issues when "user error" is not the problem!

Sometimes I wish Aerotech would be a bit more selective on the warranties that they do honor, or that we, as users of the equipment and reloads, would be more honest with ourselves as to whether the issue was really, truly a problem with the hardware or reload... Yes, it stings when $200 in hardware and reload go up in smoke, potentially destroying your $500 project with countless hours of labor invested, but as Rick mentioned, there are a lot of "user error" issues on assembly that lead to motor failure, and because they're difficult to show conclusive evidence one way or another, AT will typically honor the warrantee, even if it may be or is likely a user error. That's great, except for the fact that they need to cover the cost of the warrantee replacements... Nothing is free, after all. So ALL USERS end up paying for all of those warrantee replacement hardware bits and reloads in the form of increased prices.

One option, would be to simplify the assembly of the motor - I believe this is the direction AT was going when they released the RMS-EZ reloads, where the delay assembly was fully assembled. However, we all know how that ended up. Another option would be to put some serious effort into making the instructions provided with each reload more accurate and easier to understand for those who may not be used to the way the motors go together. But then you have the problem of those people (including myself) who don't always use the instructions because "I've build this reload dozens of times"... It's difficult to make something idiot-proof - they keep inventing new kinds of idiots. :)
 
I recently burned an AT J180T with normal motor function. When I attempted to clean the motor hardware, after it cooled, I discovered that the phenolic liner was essentially welded or melted to the inside of the motor casing and can not be removed. I did use a generous coating of Super Lube on the outside of the liner when I assembled the motor about an hour before the flight and I'm certain that I followed the assembly instructions correctly. I've never had this happen before and was wondering if anybody else has. Does anybody know any procedure for removing the liner in this situation without damaging the hardware or am I just going to have to buy a new 54/852 case?

IMG_0376.jpeg
 
Here's a copy of my post in the J180T problem thread. I make D grain reloads for Aerotech cases and this is the method I use to remove stuck liners. I do not grease liners in Aerotech or CTI motors.

You greased the liner, now it's glued in. The C-slot core allows heat build up on the side with the slot.You will need a seal disk without O-ring, some WD40 or other penetrating oil, and a piece of wood dowel at least 1" diameter.
Apply WD40 to both ends of liner and allow it to suck in between liner and case. Let sit for at least an hour. Insert seal disk into one end of liner. Put other end of case on a soft surface and push out the liner using the wood dowel. If it still won't move, use a hammer on the wood to get it started moving, then push it out. You can use steel wool to get the remaining gunk out of the case.
 
I recently burned an AT J180T with normal motor function. When I attempted to clean the motor hardware, after it cooled, I discovered that the phenolic liner was essentially welded or melted to the inside of the motor casing and can not be removed. I did use a generous coating of Super Lube on the outside of the liner when I assembled the motor about an hour before the flight and I'm certain that I followed the assembly instructions correctly. I've never had this happen before and was wondering if anybody else has. Does anybody know any procedure for removing the liner in this situation without damaging the hardware or am I just going to have to buy a new 54/852 case?

View attachment 400593

Gently heat the case in an oven (less than 200°) or with a heat gun on a moderate setting. Then grab the case with a oven mitt and push the liner out with a seal disc and a stick.
The last three I burned at LDRS, I did not grease the liners.
 
Gently heat the case in an oven (less than 200°) or with a heat gun on a moderate setting. Then grab the case with a oven mitt and push the liner out with a seal disc and a stick.
The last three I burned at LDRS, I did not grease the liners.
I like the seal disc on a stick...but prefer a well lubricated liner...just personal preference.
 
...........which is correct???

Yes :cool:

*I joke. This is one of the many beautiful facets of rocketry where there is no single right answer. In such cases you can ask 3 people and get 4 answers. Maybe the best answer I've gotten to these situations is "Try both, see what works best for you"
 
Yes :cool:

*I joke. This is one of the many beautiful facets of rocketry where there is no single right answer. In such cases you can ask 3 people and get 4 answers. Maybe the best answer I've gotten to these situations is "Try both, see what works best for you"

And the really funny thing about that piece of advice is that you'll do it one way for 3 burns, and the 4th time it'll be all different, all over again!
 
And the really funny thing about that piece of advice is that you'll do it one way for 3 burns, and the 4th time it'll be all different, all over again!

I always try to remove the linear and remnants ASAP after the flight. IMHO it might have prevented this stuck situation.

I wonder if their are people who swear by delaying the clean up is easier.:music1:
 
I'd like to know why there are no more G80-4's. Indeed, any SU G80. Are the G79,78,77's just as good?

The G80 is offered in the 14 second adjustable format as a DMS motor as well as 7, 10 and 13 second delays. The G80 is the most powerful of the G's that you listed so you're gonna get a bigger push.
 
Thanks for the reply. The "K" motor flight is still in the future. So,with this motor just leave out the election charge and let the electronics handle the deployment?

You can leave out the BP and then the delay element will become a nice smoke element. You could also go with backup motor ejection along with your electronics.
 
I always try to remove the linear and remnants ASAP after the flight. IMHO it might have prevented this stuck situation.

I wonder if their are people who swear by delaying the clean up is easier.:music1:

I’ve also noticed that it is easier to remove the liner as soon as practicable. Once I left a liner in until I got home from a launch and it took me 3 days to extract it.

Since then I extract as soon as I can. Gloves help to hold the hot casing.
 
Does Aerotech have plans to make a G64-6? 8 is too long for some rockets and 4 is too short. Flew a PML Mini BBX on a G64-4 and it was too short (needed a 6). Being quantum there was no damage but how long will that last?
 
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