3 New Aerotech motor certifications and motor files

Charles_McG

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Thanks for posting the information on these new motors. Unfortunately the are all HPR motors. The motor I was hoping for would essentially be an F10 stretched to 120NS. That is the motor I would buy and fly. It would be the ideal motor, along with two D21s, to fly in single stage Competition evens such as G Super Roc, not that will ever be flown again. In events with staging allowed, an E30 or such would start it off nicely.

Of course the low thrust HPR full G is just the ticket for an awesome Class 1 rocket, when kicked off with an F80 or such first stage. Although that may be pointless with out a visible coasting trail.

Why do you say they are HPR motors? 150-160Ns, <80N, <125g propellant, non-sparky. Looks LPR to me. You'll just need to fly altimeter-deployment.
 

Alan15578

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Why do you say they are HPR motors? 150-160Ns, <80N, <125g propellant, non-sparky. Looks LPR to me. You'll just need to fly altimeter-deployment.

That would be nice, but any motor with >62 grams of propellant is not a MR motor.
 

Alan15578

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Not quite true. Model rocket motors are limited to 125 grams or less by NFPA 1125. Model rocket motors which have more than 62.5 grams may not be sold to people under 18. Section 7.6 of NFPA 1125, 2017.

I'm old, I don't fly HPR, and things seem to have changed for the better. I just checked the NAR website and my earlier post seems to be in error. I look forward to buying the new 160N-S long burn motor, without being an HPR certified consumer. Now if we could just get rid of that 80N thrust limitation... I apologize for any confusion I have caused. Nevertheless, I would still like a 120 N-S end burning 29mm composite propellant motor for potential contest use.

Alan Jones
 

LithosphereRocketry

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I'm old, I don't fly HPR, and things seem to have changed for the better. I just checked the NAR website and my earlier post seems to be in error. I look forward to buying the new 160N-S long burn motor, without being an HPR certified consumer. Now if we could just get rid of that 80N thrust limitation... I apologize for any confusion I have caused. Nevertheless, I would still like a 120 N-S end burning 29mm composite propellant motor for potential contest use.

Alan Jones

Why limit yourself? Just curious why 120Ns would be better than 150. Are you worried about thrust-to-weight ratio with the extra propellant mass?
 

Alan15578

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Why limit yourself? Just curious why 120Ns would be better than 150. Are you worried about thrust-to-weight ratio with the extra propellant mass?
Because 150+20+20=190>160. I don't care about propellant mass, as long as I say below 125g. total.
 

Alan15578

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There is no limitation for total rocket mass to 125 g. There are three classes of rockets, with Class 1 (model rockets) limited to 1500 grams and under, with propellant mass under 125 grams.
Steve, your reading comprehension may be slipping. ;) You have to comprehend all responses in the context of the discussion tread. My arithmetic is all in N-S, although I don't know where Litho's 150 came from (probably a typo of 160). My 125g is clearly the continuation of a sentence about propellant mass and should not be misconstrued to be GLM. Your post is also incomplete in that you claim there are three classes of rockets, but you only define one class. ;)

In the context of NAR sanctioned competition (read previous messages in this thread), there are many "classes" of rockets. In particular G superroc altitude is limited to single stage model rockets powered by 80.01 to 160 N-S of certified total impulse. I could not fly a rocket with 190 N-S of total impulse in that event. I would not fly the new 160 N-S motor in that event, even if you might. I would however, fly a 120 N-S composite endburner, essentially a stretched F10, clustered with two D21 motors in that competition event. Aerotech has proven that they can make and certify long burning motors. Their three new motors are interesting, but not the motor that I most want to buy and fly. I was hoping that one of their new motors would be the one I want. I'm still hopeful for such a motor.

Model rocketry, HPR, amateur, professional, it's all good!

Alan Jones
L0 and proud of it.
 

rcktnut

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Your post is also incomplete in that you claim there are three classes of rockets, but you only define one class. ;) (Quote malfunction ???)



I think Steve was keeping his reply as to your situation.
 
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Steve Shannon

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Steve, your reading comprehension may be slipping. ;) You have to comprehend all responses in the context of the discussion tread. My arithmetic is all in N-S, although I don't know where Litho's 150 came from (probably a typo of 160). My 125g is clearly the continuation of a sentence about propellant mass and should not be misconstrued to be GLM. Your post is also incomplete in that you claim there are three classes of rockets, but you only define one class. ;)

In the context of NAR sanctioned competition (read previous messages in this thread), there are many "classes" of rockets. In particular G superroc altitude is limited to single stage model rockets powered by 80.01 to 160 N-S of certified total impulse. I could not fly a rocket with 190 N-S of total impulse in that event. I would not fly the new 160 N-S motor in that event, even if you might. I would however, fly a 120 N-S composite endburner, essentially a stretched F10, clustered with two D21 motors in that competition event. Aerotech has proven that they can make and certify long burning motors. Their three new motors are interesting, but not the motor that I most want to buy and fly. I was hoping that one of their new motors would be the one I want. I'm still hopeful for such a motor.

Model rocketry, HPR, amateur, professional, it's all good!

Alan Jones
L0 and proud of it.

Thanks for the explanation.
 

burkefj

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I was nagging Aerotech to find out when I could order the G-11 and G-12 and finally got this from Karl, bummer...

Hi Frank,

The G11 and G12 did not pass the thermal requirement test, the G8 did, so moving forward
The G8ST will be available soon. We will rethink the G11 and G12 to reduce the heat at the
Aft end in the future…

Best,
Karl
 

djs

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G8 is the most important :) G11 and G12 are just too fast....
 

Alan15578

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I was nagging Aerotech to find out when I could order the G-11 and G-12 and finally got this from Karl, bummer...

Hi Frank,

The G11 and G12 did not pass the thermal requirement test, the G8 did, so moving forward
The G8ST will be available soon. We will rethink the G11 and G12 to reduce the heat at the
Aft end in the future…

Best,
Karl

So how and why when this this tread was started with :

Hello,

TMT has tested and certified the 3 Aerotech motors. They are two 29mm Super Thunder end burners- the G11 and G12
 

burkefj

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Apparently even though tmt certified them thet did not pass some thermal criteria post burn, ie they got very hot, I'm not sure if this is nfpa or some other criteria...we'd have to ask Karl, point is they won't be selling them as is for now.
 

slothead

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Hello,

TMT has tested and certified the 3 Aerotech motors. They are two 29mm Super Thunder end burners- the G11 and G12. Also tested was the J520, which is now certified for delay use versus its previously plugged forward closure only configuration.
Are you suggesting that the J520 was the third motor certified? And if so which size (diameter) was this J520?

Thanks,
Tom
 

dhbarr

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j520w was previously certed in a plugged config, but is now certed with delay / motor eject. It is still 38mm.
 

Alan15578

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Apparently even though tmt certified them thet did not pass some thermal criteria post burn, ie they got very hot, I'm not sure if this is nfpa or some other criteria...we'd have to ask Karl, point is they won't be selling them as is for now.

This is not the response I was expecting. I've been waiting for the other shoe to drop. Who signed off on these TMT motor certifications? Did they issue a subsequent formal motor decertification? Were there any repercussions from the NFPA for improper motor testing and certification?
 

Steve Shannon

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This is not the response I was expecting. I've been waiting for the other shoe to drop. Who signed off on these TMT motor certifications? Did they issue a subsequent formal motor decertification? Were there any repercussions from the NFPA for improper motor testing and certification?

As soon as TMT Chair Alan Whitmore realized the mistake he notified Aerotech. As the chair of TMT Alan Whitmore “signs off” all certifications, but as the President of Tripoli I am ultimately responsible. We have discussed implementing a checklist of criteria to ensure that this kind of mistake isn’t repeated. There were no repercussions with NFPA, but NFPA isn’t a regulatory organization.
 

Alan15578

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As soon as TMT Chair Alan Whitmore realized the mistake he notified Aerotech. As the chair of TMT Alan Whitmore “signs off” all certifications, but as the President of Tripoli I am ultimately responsible. We have discussed implementing a checklist of criteria to ensure that this kind of mistake isn’t repeated. There were no repercussions with NFPA, but NFPA isn’t a regulatory organization.

Thanks. What was the actual date of the certifications, and the actual date of the decertifications? I realize that the NFPA is not an enforcement agency, but they do set the requirements for certifying sport motors for most states and local fire marshals. They may also recognize NAR S&T and Tripli TMT as motor certifying labs.
 

Steve Shannon

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Thanks. What was the actual date of the certifications, and the actual date of the decertifications? I realize that the NFPA is not an enforcement agency, but they do set the requirements for certifying sport motors for most states and local fire marshals. They may also recognize NAR S&T and Tripli TMT as motor certifying labs.

I don’t know the dates. Alan notified Mark of the test results. Mark handled all the announcements. That was his role with TMT; he wrote the certification letters and when necessary the decertification notices. When he volunteered it was a natural fit because he was already collecting the test data and putting it into ThrustCurve and motor files for RockSim and OpenRocket on his website.
I think you could probably assume the certification date is the date of the announcement in post 1 of this thread. I don’t remember when the mistake was discovered and I haven’t been able to find it in my emails.
 

beeblebrox

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Charlie gave me a G12 to demo at Hellfire but the lightest rocket I have with dual deployment is a Wildman Darkstar Mini. It weighs a pound and a half. That’s about twice the weight that is safe to fly with the G12. The thrust curve on the side of the motor says it gets about 4 pounds of thrust initially and then settles in at about 2.5 pounds after the initial kick.

Because the motor doesn’t have an ejection charge, it needs electronics. So I built an Apogee Aspire with dual deploy. It should come in under 12 ounces. It still needs paint, sheer pins, and ground testing, but I should be able to fly it at Airfest this week.

Joe

This motor is key to an awesome monocopter or RC model aircraft flight!!!
 
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