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Tomar
Mission Specialist
Joined: Jul 15, 2007
Posts: 18
Location: Glendale, AZ
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 Posted: Mon Sep 14, 2009 9:24 am Post subject: Pro38 J400SS Issue |
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I attempted to fly a J400SS (6 grain) motor this past weekend and found the reload too long for the case. I had planned to use this for a Level 2 certification but had to go to my backup plan and flew a Pro38 J330.
What I found was the reload was about 1/4 inch too long for the case and the threads would not engage in the aft closure. After retruning home I measured the length and weighed each grain (reassembled with each grain in its proper position). Paul Holmes inquired about this and I've been having an email exhagne with hime.
Has anyone else had this issue with the J400SS or any Pro38 loads?
Mark Saunders
Glendale, AZ
NAR 78825 L2
TRA 09247 |
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troj
Fleet Captain
Joined: Jun 30, 2007
Posts: 1506
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| Posted: Mon Sep 14, 2009 10:15 am Post subject: |
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That's not something I've ever seen.
Was the liner too long, as well? Or was it just the grains?
-Kevin |
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Tomar
Mission Specialist
Joined: Jul 15, 2007
Posts: 18
Location: Glendale, AZ
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| Posted: Mon Sep 14, 2009 11:46 am Post subject: |
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| troj wrote: | That's not something I've ever seen.
Was the liner too long, as well? Or was it just the grains?
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I dunno, but I will measure the liner against a J330 when I get home. I believe the liner is fine. The grain stack is fully inserted and tops and bottoms of grains are touching. The aft closure is touching the bottom grain and the forward closure is touching the top grain. Each grain is 60mm long except the bottom grain whihc is 59mm long.
I'm really scratching my head on this one. I'll be contacting CTI with this query.
Mark Saunders
Glendale, AZ
NAR 78825 L2
TRA 09247 |
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troj
Fleet Captain
Joined: Jun 30, 2007
Posts: 1506
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| Posted: Mon Sep 14, 2009 1:28 pm Post subject: |
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| Tomar wrote: | | I'm really scratching my head on this one. I'll be contacting CTI with this query. |
Yeah, especially with every grain being exactly the same length.
I wonder if maybe you ended up with XL grains, instead of standard grains? I don't know the length of either off the top of my head.
Regardless, I'm sure CTI will take care of you.
-Kevin |
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Tomar
Mission Specialist
Joined: Jul 15, 2007
Posts: 18
Location: Glendale, AZ
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| Posted: Mon Sep 14, 2009 2:03 pm Post subject: |
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Kevin,
I don't think it is an XL problem unles the XL grains were around 4 years ago. This motor, and the J330, has been in storage for 4 years.
BTW, I'll be recertifying for L3 next month. Just enough time to dust off the BIG Thor from my 2004 certification flight and get her ready to go.
Mark Saunders
Glendale, AZ
NAR 78825 L2
TRA 09247 |
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Tomar
Mission Specialist
Joined: Jul 15, 2007
Posts: 18
Location: Glendale, AZ
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| Posted: Mon Sep 14, 2009 6:39 pm Post subject: Problem solved! |
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Ok, more information.
The date code on the reload is August 11, 2002. Its a really old reload.
I compared it to a J330 and they are exactly the same length. I fit the J330 in the case no problem. I could not get the J400SS in the case all the way. I noticed the aft opening of the case has a slight flat spot like it got dropped. I tried fitting the J400SS in another 6 grain case I have and it fit. I went back to the original 6 grain case and it does not fit. I believe the boogered up threads are the problem. Good thing I have two and three of each case.
Oh and I have an AT H123W in the package from before the AT fire. I had several of those and flew some in 2004 without any problems. I will see how this one performs at our October launch. 
Mark Saunders
Glendale, AZ
NAR 78825 L2
TRA 09247 |
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troj
Fleet Captain
Joined: Jun 30, 2007
Posts: 1506
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| Posted: Mon Sep 14, 2009 7:38 pm Post subject: |
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Sounds like the problem is solved!
-Kevin |
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Tomar
Mission Specialist
Joined: Jul 15, 2007
Posts: 18
Location: Glendale, AZ
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| Posted: Mon Sep 14, 2009 7:49 pm Post subject: Propellant |
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Kevin,
Before I let this thread go, who's got the best prices on propellant these days. I've not been back in long enough to know. I need to get an M1315W or M1550R by Oct 24 for my L3 again.
Mark Saunders
Glendale, AZ
NAR 78825 L2
TRA 09247 |
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troj
Fleet Captain
Joined: Jun 30, 2007
Posts: 1506
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| Posted: Tue Sep 15, 2009 6:05 am Post subject: Re: Propellant |
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| Tomar wrote: | | Before I let this thread go, who's got the best prices on propellant these days. I've not been back in long enough to know. I need to get an M1315W or M1550R by Oct 24 for my L3 again. |
I'll be honest, I can't answer that -- I tend to be biased towards vendors I've had positive experiences with, and those who support launches that I attend.
Currently, this means Wildman Kentucky and Off We Go Rocketry, as they both come to our launches here in Nebraska.
I think prices are pretty even across all the vendors, but I don't know that for certain.
-Kevin |
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Rubr_Duky
Pad Monkey
Joined: Jul 01, 2007
Posts: 543
Location: Fullerton, CA
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| Posted: Tue Sep 15, 2009 9:41 pm Post subject: |
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Find your launch site, and contact the vendor that regularly attends. You might even get some competition - our local site has three motor vendors most of the time.
Eliminates shipping, you can usually negotiate for a buddy price and/or no tax, or at the very least, know you'll have it by your date.
_________________
RD
TRA #10462 L2
www.rocketryonline.com |
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Tomar
Mission Specialist
Joined: Jul 15, 2007
Posts: 18
Location: Glendale, AZ
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| Posted: Tue Sep 15, 2009 9:45 pm Post subject: |
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Unfortunately we do not have an on-site vendor any more or I would get it from them.
_________________
Mark Saunders
Glendale, AZ
NAR 78825
TRA 09247 L3 |
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