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L1 Motor Must be Unopened?

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mccordmw

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Maybe I'm imagining things. I can't find it in search, but I seem to recall reading somewhere that for the L1 NAR certification flight, I have to present my rocket motor unopened and assemble it before flight. Is that right? Or am I dreaming? I also read the L1 form and didn't see it. *shrug*

Maybe I'm just getting paranoid as my L1 cert flight approaches in Sept. (please don't blow up)
 

mccordmw

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Oh I found it!

4. The modeler must demonstrate his ability to build and fly a rocket containing at least one H or I impulse class motor. Cluster or staged models used for certification may not contain over 640.00 Newton seconds total impulse. In the case of a cluster or staged model, at least one of the individual motors must be an H or I impulse motor. Combinations of D, E, F or G motors that meet the impulse requirements do not qualify as the model does not contain at least one H or I impulse motor. Single use, reloadable, or hybrid technology motors are permitted. The modeler must assemble the reloadable motor, if used, in the presence of a certification team member.

I guess that means I can open it and practice ahead of time. It just needs to be disassembled before cert?
 

djs

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The motor should be assembled in front of your cert team. I don't know about unopened. The goal is generally that the cert team feels comfortable that you assembled the motor correctly. In some cases, like a CTI 29 or 38mm motor, this is pretty easy to tell. With an AT motor, it's a little harder.
 

djs

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I guess that means I can open it and practice ahead of time. It just needs to be disassembled before cert?

Yes- you must be able to assemble/dissasemble the motor blindfolded, in 30 seconds or less. Bonus points for chanting "THIS IS MY VMAX, THIS IS MY BLUE THUNder- THIS IS FOR FLYING, THIS IS FOR MY L1" while doing it.
 

Rex R

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this is not a bad thing, one can usually ask the cert team 'did I get it right?'. when I did my l1 cert, my cert team offered helpful suggestions as we huddled in the heated restroom(early March) while I built the motor.
Rex
 

mccordmw

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this is not a bad thing, one can usually ask the cert team 'did I get it right?'. when I did my l1 cert, my cert team offered helpful suggestions as we huddled in the heated restroom(early March) while I built the motor.
Rex
Yes. I'd rather be corrected than blow up my rocket.
 

Rex R

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I would imagine that the 'unopened' bit is to ensure that the motor is certified and is big enough to get the job done(not to mention keeping all the parts together prior to the build:)).
Rex
 

djs

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I've been practicing putting it together with my feet.
PRIVATE MCCORDMW! DO YOU THINK YOU'LL BE IN ACTION AT THE LAUNCH SITE WITH BARE FEET? I DON'T THINK SO! YOU WILL ASSEMBLE YOUR MOTOR WITH YOUR BOOTS ON, LIKE GOD AND THE NAR INTENDED!

NOW DROP AND GIVE ME 20 PARACHUTE PACKINGS! I DON'T WANT TO SEE ANY SHROUD LINES STICKING OUT, YOU UNDERSTAND?!
 

rstaff3

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I would say opening it is fine but maybe the packaging should be kept. But, the very best way is to get the name of the person or persons who will be witnessing the flight and check with their interpretation in advance.
 

Bat-mite

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Never heard the unopened thing before. But Dick is right, talk to whomever will be signing off for you.
 

CORZERO

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Getting to know my prefect RSO's and keeping an open line of communication with them via email has quashed a lot of speculation regarding rules I do not understand as well as add clarity to their own club policies and procedures.
 

mccordmw

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I think some Aerotech loads need to be glued in. I would assume you have to assemble those ahead of time. Perhaps a video or pic showing assembly would suffice. I found a good C-star video for L3 documentation.

[video=youtube;JYYYqeniVwE]https://www.youtube.com/watch?v=JYYYqeniVwE[/video]
 

rstaff3

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The only ones I ever glued (38mm end burners) were glued on-site with 5-min epoxy. Again, it's best to discuss it in advance.
 

djs

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I would suggest avoiding something that requires grain gluing for your L1 flight- you'll already be nervous about the motor assembly- no need to add a new technique while doing it.
 

rstaff3

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I would suggest avoiding something that requires grain gluing for your L1 flight- you'll already be nervous about the motor assembly- no need to add a new technique while doing it.
+1 on that
 

samb

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Oh I found it!

4. The modeler must demonstrate his ability to build and fly a rocket containing at least one H or I impulse class motor. Cluster or staged models used for certification may not contain over 640.00 Newton seconds total impulse. In the case of a cluster or staged model, at least one of the individual motors must be an H or I impulse motor. Combinations of D, E, F or G motors that meet the impulse requirements do not qualify as the model does not contain at least one H or I impulse motor. Single use, reloadable, or hybrid technology motors are permitted. The modeler must assemble the reloadable motor, if used, in the presence of a certification team member.

I guess that means I can open it and practice ahead of time. It just needs to be disassembled before cert?
If you've built a 24/40 or 29/40-120 motor you wont need a whole lotta practice. Or you could pick an Aerotech DMS or Cesaroni motor for one less thing to worry about. :)
 

DavidMcCann

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I would suggest avoiding something that requires grain gluing for your L1 flight- you'll already be nervous about the motor assembly- no need to add a new technique while doing it.
I don't know of any L1's that need glue....could be wrong
 

mccordmw

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I49 and I59
Is that still the case? Their instructions say,

"Fig.-1: If the propellant grain is not already bonded tothe liner at the factory, bond the grain to the liner using
a quick cure (5, 15 or 30 minute) epoxy, flush with one
end. This prevents the grain from moving during flight"

So it's not normally bonded in those sizes?

I'm using CTI, so not a problem.
 

rstaff3

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Is that still the case? Their instructions say,

"Fig.-1: If the propellant grain is not already bonded tothe liner at the factory, bond the grain to the liner using
a quick cure (5, 15 or 30 minute) epoxy, flush with one
end. This prevents the grain from moving during flight"

So it's not normally bonded in those sizes?

I'm using CTI, so not a problem.
I didn't look at the new instructions, when I used them you had to glue them. So, maybe I AM wrong.
 

mccordmw

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What altitude are you expecting with that?
I built a L1 / L2 rocket. Build thread: http://www.rocketryforum.com/showthread.php?131715-Binder-Design-Excel-Plus-54mm-Build-Thread

Stats are:

L1
Motor: CTI I242 38mm 4-grain
Stability caliber: 2.2
Initial thrust-to-weight: 286 N (64 lb-force) / (6 lb rocket) = 10.6:1 ratio
Velocity off rail (assuming an 8 ft rail): 19.4 m/s
Max acceleration: 106 m/s^2
Max velocity: 184 m/s (412 mph / mach 0.54)
Apogee: 995 m (3265 ft.)

L2 (pull out the Aeropack 38mm to 54 mm adapter):
Motor: CTI K160 54mm 4-grain
Stability caliber: 1.13
Initial thrust-to-weight: 245 N (55 lb-force) / (5 lb rocket) = 11:1 ratio
Velocity off rail (assuming an 8 ft rail): 18.5 m/s
Max acceleration: 84 m/s^2
Max velocity: 241 m/s (540 mph / mach 0.72)
Apogee: 2431 m (7976 ft.)
 

Viking

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... The modeler must assemble the reloadable motor, if used, in the presence of a certification team member.
...
No, this means you must assemble after it has been used.
Semantics.
Yes, I'm being silly. Ideally, Rules/Regulations should not be ambiguous.
Should probably be written along the lines of... "If a reloadable motor will be used for the certification flight, the modeler must assemble the motor in the presence of a certification team member"
;)
 

Bat-mite

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Or, "The modeler must assemble the reloadable motor, if one will be used, in the presence of a certification team member."

This is what happens when engineers try to write documentation. :wink:
 

watermelonman

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The text of an unopened reload sounds an awful lot like a holdover, or even copy and paste, from the NAR competition rules. Those rules are crazy, with regulation over the reload packaging being handed over, inspected, then handled back to the competitor, to be assembled in some closely monitored and partitioned off area at a launch site. Maybe a body cavity check before entering the motor assembly area too. Crazy, but justifiably crazy, when you consider how easy it would be to cheat a low power competition with reloadable motors.

In reality no one wants to watch you assemble a Cesaroni 29mm or 38mm motor. Do not forget spacers, and that is about it. An Aerotech in this size is a little more involved, but anyone familiar could probably open up one end or even simply ask a question or two to determine if you should fly or not.

Speaking of Cesaroni, I see someone talking about dissembling and re assembling a motor. Please, please, please do not do this with 38mm Cesaroni motors. You are begging for problems. One time is probably fine if you are careful with the plastic threads, but in general reassembly is not a good idea for those reloads.
 

mccordmw

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Speaking of Cesaroni, I see someone talking about dissembling and re assembling a motor. Please, please, please do not do this with 38mm Cesaroni motors. You are begging for problems. One time is probably fine if you are careful with the plastic threads, but in general reassembly is not a good idea for those reloads.
Yeah. I have my 38mm I242. Looks like it's already all put together in its sleeve. All I need to do is take the paper off the top to remove the black powder since I'm doing electronically controlled dual deploy. Then it's just simply screwing the motor into the CTI case. I can see how they would want to check and make sure it's proper screwed into place.
 

samb

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Maybe I'm imagining things. I can't find it in search, but I seem to recall reading somewhere that for the L1 NAR certification flight, I have to present my rocket motor unopened and assemble it before flight. Is that right? Or am I dreaming? I also read the L1 form and didn't see it. *shrug*

Maybe I'm just getting paranoid as my L1 cert flight approaches in Sept. (please don't blow up)
...

I guess that means I can open it and practice ahead of time. It just needs to be disassembled before cert?

I'm certifying on a CTI 38mm I242 4G White. I should be ok.

Ok, relax. :) Cesaroni reloads require zero practice IMO.

Watch the video: [video=youtube;2EFChga49VQ]https://www.youtube.com/watch?v=2EFChga49VQ[/video]

Bring the motor on launch day and assemble it in the presence of your cert team. Light the candle and celebrate your success. :cheers:
 
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Viking

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Or, "The modeler must assemble the reloadable motor, if one will be used, in the presence of a certification team member."

This is what happens when engineers try to write documentation. :wink:
That would work too, it better follows SVO(Subject, Verb, Object) Syntax for English than mine does, though the action preceding the conditional statement doesn't sit right with me.
The syntax of mine was like the If-Then(-Else) conditional statement in programming, the 'Else' would be an SU motor which wouldn't need to be described.

Can you tell I'm an engineer? ;) And yep, I do a lot of documentation.
Probably half my unproductive time at work is reading specs, regulations and legal documents and I pick those to death too, I hate ambiguous and conflicting specifications.... such a waste of my time.
The remainder of my unproductive time is emails (uuurgh) and meetings (uuuuurrrggghhh!)
My productive time is drawings and documentation, with a little procurement thrown in for something different :D
 
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