Redesigned J1999N-P Certified by TMT

[AeroTech]

AeroTech Information Release

8/16/10

Redesigned J1999N-P Certified by TMT

The J1999N-P reload for the RMS-54/1280 motor hardware has been redesigned by AeroTech and certified by Tripoli Motor Testing (TMT) as the J1799N-P.

The J1799N-P replaces the J1999N-P that was decertified by TMT and withdrawn from sale after a number of failures were experienced by consumers during LDRS-29. The J1799N-P delivers a total impulse of 1066 N-sec over a burn time of 0.60 seconds with a peak thrust of over 476 pounds.


Aaron Stanley`s 54mm minimum diameter WhipLash flying on a J1799N-P reload at Aeronaut 2010. Photo by Kenneth.

AeroTech has produced a "repair kit" that consumers possessing unfired J1999N-P reloads manufactured prior to July 2010 will be able to obtain at no cost through any authorized AeroTech high-power dealer. This kit includes three replacement propellant grains, a new nozzle, grain spacer o-rings and revised instructions. Customers are requested to return their unfired J1999N-P nozzle(s) and instructions to their dealer to receive the repair kit.

The complete J1799N-P reload kit will be available for purchase from AeroTech’s dealers at a suggested retail price of $119.99 each. AeroTech anticipates shipments to its dealers to begin in approximately 2 weeks. The J1799N-P is being submitted to the California Office of the State Fire Marshal (OSFM) for approval of sale & use in California.

Motor instructions and an assembly drawing for the J1799N-P are now available for download in PDF format from the AeroTech Resource Library at http://www.aerotech-rocketry.com.

AeroTech Consumer Aerospace has a page on Facebook! Follow the very latest AeroTech news, information, product developments and testing at http://www.facebook.com/pages/AeroTe...e/159005948954


AeroTech Consumer Aerospace is a division of RCS Rocket Motor Components, Inc., Cedar City, UT.

[stickershock23]

Picture of my rocket WhipLash flying a J1799N at Aeronaut 2010. Photo by Kenneth.

So does anyone know if the actual problem that caused the failures was found? or was the motor just get wimpied down so any problem will be compensated for?

the reason I ask between myself and a couple friends we have several warp 9 reloads, and none of us trust flying them. because if there is a problem with one type there might be one with another.. afterall it is the same propellant.

Either that or We would be willing to sell them CHEAP so we dont have to worry about it. you take the risk.

[Donaldsrockets]

Which particular reloads do you have???

I personally have never heard of any W9 failures other than the J1999N and the G69N EB when users didn't inhibit the end of the grain with grease as mentioned in the instructions.

[cjl]

So does anyone know if the actual problem that caused the failures was found? or was the motor just get wimpied down so any problem will be compensated for?

the reason I ask between myself and a couple friends we have several warp 9 reloads, and none of us trust flying them. because if there is a problem with one type there might be one with another.. afterall it is the same propellant.

Either that or We would be willing to sell them CHEAP so we dont have to worry about it. you take the risk.

Honestly, I wouldn't worry about it too much. The J1999 is the only one that I've seen fail. I've seen a bunch of I1299s used in quite impressive flights, as well as the H999 and a couple of the endburners, and all of them worked perfectly.

[Rocketjunkie]

I had a J99 fail. Built exactly per the instructions with epoxy inhibitor. I have another, unassembled. Still waiting on the warranty replacement

[stickershock23]

Yeah I think there is something else going on that needs to be figured out.
And just putting a bandaid on a reload and not fixing the actual problem does not make me confident the problem is fixed.

What reloads do I have? I don't know for sure I have a daybox for our club, so I store quite a few I'd have to go through them. I think we (everyone that I store for) agrees we are not confident in the ones we have for a while.

They may be perfect, bu tis it worth the risk? I personally would rather throw the motor away that take a chance of blowing up my rocket. reloads are cheap, my rocket and my time building it is not. but again thats just my personal opinion. I mean you fly enough and sooner or later your gonna damage a rocket one way or another. Why add to that risk.

[Rocketman248]

I think the main problem with the motor was that it was just a little too "on the edge." I think the changes they did were more than just putting a bandaid on it. I am fully confident in the changes and I plan on flying several of these motors.

Can't wait to get my hands on some!

[5x7]

Yeah I think there is something else going on that needs to be figured out.
And just putting a bandaid on a reload and not fixing the actual problem does not make me confident the problem is fixed.

What reloads do I have? I don't know for sure I have a daybox for our club, so I store quite a few I'd have to go through them. I think we (everyone that I store for) agrees we are not confident in the ones we have for a while.

They may be perfect, bu tis it worth the risk? I personally would rather throw the motor away that take a chance of blowing up my rocket. reloads are cheap, my rocket and my time building it is not. but again thats just my personal opinion. I mean you fly enough and sooner or later your gonna damage a rocket one way or another. Why add to that risk.

It's fixed and tested, no more risk than any other reload. Every company has CATOs, its a risk but a small one, and no different than any other reload. I think you may be more sensitive than the average person. Most people don't build rockets that could go in Museums.

[RangerStl]

This kit includes three replacement propellant grains, a new nozzle, grain spacer o-rings and revised instructions.

Band-Aide? Looks like a totally new motor. New grains, new nozzle, new spacer, new o-rings, new instructions.

[Rocketman248]

Most people don't build rockets that could go in Museums.

That's true. Mark's creations are freakin amazing!

Mine on the other hand...

[stickershock23]

It's fixed and tested, no more risk than any other reload. Every company has CATOs, its a risk but a small one, and no different than any other reload. I think you may be more sensitive than the average person. Most people don't build rockets that could go in Museums.

I will take that as a compliment.. Thank you.. But not all my rockets are That cool I just like to do one AWESOME one every once in a while.

Let me bottom line this... THIS IS WHAT I HEARD, I HOVE NO EVIDENCE FIRST HAND. I heard it was voids in the grains.. caused by the way the grain was cast. By shortening the grains gluing them, and adding an o-ring then opening up the nozzle you are NOT fixing that problem, you are making the motor more forgiving if that is The problem.

So My question. WAS there a grain casting problem? (again It was a rumor from GOOD sources) and if there was a grain problem did that get fixed too? If so, then I would feel safe with New motors, but still would Question old one. If it's NOT true and the grains need to be glued etc. I we could do that to the reloads we have and feel safe about flying them (yes then they would no loger be certified. but we do have an EX launch so that is good with us)

I am thinking maybe I should talk to Judo with his mobile X-Ray machine and have him X-ray these grains.. that will answer the question about the ones on hand RIGHT NOW LOL

[stickershock23]

It's fixed and tested, no more risk than any other reload. Every company has CATOs, its a risk but a small one, and no different than any other reload. I think you may be more sensitive than the average person. Most people don't build rockets that could go in Museums.

I will take that as a compliment.. Thank you.. But not all my rockets are That cool I just like to do one AWESOME one every once in a while.

Let me bottom line this... THIS IS WHAT I HEARD, I HOVE NO EVIDENCE FIRST HAND. I heard it was voids in the grains.. caused by the way the grain was cast. By shortening the grains gluing them, and adding an o-ring then opening up the nozzle you are NOT fixing the problem, you are making the motor more forgiving if their is a problem.

So My question. WAS there a grain casting problem? (again It was a rumor from GOOD sources) and if there was a grain problem did that get fixed too? If so, then I would feel safe with New motors, but still would Question old one. If it's NOT true and the grains need to be glued etc. I we could do that to the reloads we have and feel safe about flying them (yes then they would no longer be certified. but we do have an EX launch so that is good with us)

I am thinking maybe I should talk to Judo with his mobile X-Ray machine and have him X-ray these grains.. that will answer the question about the ones on hand RIGHT NOW LOL

Band-Aide? Looks like a totally new motor. New grains, new nozzle, new spacer, new o-rings, new instructions.

That was just the Quick definition for lack of better words and a long description.

[karlbaum]

I congradulate Aerotech on what appears to be an excellent replacement for the J1999. The J1799 looks like an improvement to me and the photo of Aaron Stanley's rocket is outstanding. I don't know what happened to the lot of J1999s that catoed. All I can say is that Aerotech has worked very hard on making a very good motor in the J1799. Way to go Aerotech

[SCE to AUX]

So does anyone know if the actual problem that caused the failures was found? or was the motor just get wimpied down so any problem will be compensated for?

From Aerotech's Facebook page:

http://www.facebook.com/pages/AeroTe...e/159005948954

By the way, the problem with the J1999N appeared to be the aft grain casting tube melting, collapsing and plugging the nozzle, especially under high G loads. It seems to be peculiar to this particular configuration. We switched to a different casting tube material and made a few other minor changes to enhance the reliability of the motor.