I hope not. One purpose of third party certification is to remove subjectivity that might be perceived as preferential treatment.
New Motor Certified May 2019
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I hope not. One purpose of third party certification is to remove subjectivity that might be perceived as preferential treatment.
Nytrunner
Pop lugs, not drugs
Specifically, what happens when the tester gets a motor that reads (for avg thrust):
80.8
79.5
81.3
79.8
That average thrust readings average out to 80.3N's -- So is it a G80 or G81? The determination makes it either a High-power rocket motor or a model rocket motor.
The difference is technically and performance negligible, yet there's an administrative and regulatory difference that the questioner wants clarification on.
80.8
79.5
81.3
79.8
That average thrust readings average out to 80.3N's -- So is it a G80 or G81? The determination makes it either a High-power rocket motor or a model rocket motor.
The difference is technically and performance negligible, yet there's an administrative and regulatory difference that the questioner wants clarification on.
Because it averages 80.3N as per its certification data, it’s HPR. The manufacturer could call it G79, but the determination is done by the actual empirical data.
Nytrunner
Pop lugs, not drugs
Fascinating.
I may be going too far in the what-if-weeds; How are rocket motor consumers made aware that a named G79 is actually a High-power motor? Flagged as such by vendor?
I may be going too far in the what-if-weeds; How are rocket motor consumers made aware that a named G79 is actually a High-power motor? Flagged as such by vendor?
Yes. On the label or instructions is where I see it.
SecondRow
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Yes, this is what I was asking. Steve Shannon suggested that different tested lots of the same motor could result in different average thrusts. I then was curious how a motor is classified if for some of the tests it averages >80N and some <=80N (with all other specs of the motor making it low power).
I think the question has been answered. The average used for classification is the average of all the lots tested. In retrospect, that seems obvious. In my head, I was thinking lots were tested separately and those lots averages treated separately, too. I don’t know why. Thanks for indulging me.
I’m probably going to add confusion. The only test data that matter to the certification are those collected by the certification organization at the time of the most recent certification. The lot testing done by the manufacturers doesn’t affect the certification. Typically all certification samples come from a single initial batch produced by the manufacturer.
So it’s possible that the average thrust and total impulse could vary over time without changing the certification. NFPA 1125 does require the certification organization to decertify a motor if it no longer complies to various tolerances.
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I was still asleep and missed the word non.....
DaveW6DPS
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Life would be much simpler if the demarcation between high power and not were clarified.
In this case it is pretty clearly a high power motor since it is a "sparky".
But if it had 80.8 Newton average and a more conventional formula? If a motor says G79 I might not think twice about it as RSO/FSR and let it fly as low power.
It would make things easier for everyone if the designator clearly indicated which motors are high power.
In this case it is pretty clearly a high power motor since it is a "sparky".
But if it had 80.8 Newton average and a more conventional formula? If a motor says G79 I might not think twice about it as RSO/FSR and let it fly as low power.
It would make things easier for everyone if the designator clearly indicated which motors are high power.
I agree, but how do you distinguish? Motors with more than 125 grams of propellant are also HPR. So it’s possible to have a G motor that is HPR simply because of low specific impulse.
I don’t know why we have such a confusing medley of HPR conditions.
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DaveW6DPS
Well-Known Member
Exactly.
H or higher
125 Grams or more
80 Newtons average thrust or higher
Any "sparky" motor.
At 0800 Friday when 300 flyers charge the rangehead at NSL, we are supposed to remember which motor is in which category.
(Okay. maybe not "charge" exactly, but it seems like it sometimes...)
Make them bring up the label or instructions.
All CTI motors are HPR, regardless of impulse.
Most Loki motors are too, except for some G motors (I wrongly said they all were earlier).
All Estes and Quest are model rocket motors.
Aerotech puts it on their instructions according to the NFPA rules.
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For Aerotech, they appear to make HPR motor restrictions clear on their order form.
For example, look at the notes for the G75 single use motor.
https://www.aerotech-rocketry.com/u...9e23-d11d91c94390_Model_and_hp_of_5_15_19.pdf
Loki Research
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Steve, since it was brought up I need to correct you. I don't otherwise intend to poke my nose in here though.
There are 3 Loki "G" reloads that are not HP (High Power) and they are simply labeled G-whatever. Manufacturers are required to indicate that a specific G is not a "Model Rocket Motor" but a "High Power Rocket Motor" by putting "HP" in front of the motor designation on the instructions. Like HP-G94.
There may be other specifics ways of labeling but I'm not 100% sure. I do not believe it is required information anywhere else, but if you know the pertinent codes like 3.3.24.4 then you know what you are looking at motor wise, HP or not HP. Further, it is also known by the codes that all H motors are 160Ns or more total impulse and are thus HP motors by their definition. A specific label on H motors and above would be thus be redundant and so it's not used on those.
Thanks Scott. I apologize for spreading misinformation and I appreciate the correction. I didn’t realize you made any G motors. I’ll edit my post above.
Loki Research
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No worries at all. It was an honest mistake.
boatgeek
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Not to pile on, but I believe that there are lots of CTI motors that are not HPR. Most 24mm 1, 2, and 3 grain motors are less than 80 N average thrust, below H impulse, and below 125g of propellant. Likewise most of the 29mm 1-grains, about half of the 2-grains, and two of the 3-grains, plus most of the 38mm 1-grains. Is there another nuance to the HPR motor rules that I'm missing?
heada
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Exclude the sparkys because they're always HPR but yeah, lots of the smaller CTIs should be non-HPR.
shreadvector
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For California:
CTI has not had ANY of their motors CLASSIFIED by the CA State Fire Marshal as "Model Rocket Motors". They are all CLASSIFIED as "High Power Rocket Motors".
As a result, their F and G motors cannot be launched at a ny launch that operates under a "Model Rocket" launching permit.
The only way TARC teams can legally fly CTI motors is if they go to a legal/permitted HPR launch or launch on a military base with the permission of the base command.
The State law was changed as of Jan 1, 2016, so CTI could have requested the reclassification of the appropriate F and G motors as "Model Rocket Motors".
I've reminded them a few times, but they have not done so. The accident did result in their turning their attention to other higher priorities. Hopefully they can get to this before the new school year starts.....
rharshberger
Well-Known Member
I think you have it, they are not HPR's as long as the 3 conditions have been met, less than 80N average thrust, below 125g propellant, and are not sparkies. They are all HazMat however due the ignition pellets built into the top grain.
I agree, that’s what CTI could have done, but they include this warning on all of their instructions:
FOR USE ONLY BY CERTIFIED HIGH-POWER ROCKETRY USERS 18 YEARS OF AGE OR OLDER
SALE TO PERSONS UNDER 18 YEARS OF AGE IS PROHIBITED BY FEDERAL LAW
Other places on their website they refer to their different sized motors as high power motors. I don’t know why they’ve chosen to do this, but it’s their choice. Here’s their product webpage showing that they refer to all their motors as high power:
https://pro38.com/products.php
FOR USE ONLY BY CERTIFIED HIGH-POWER ROCKETRY USERS 18 YEARS OF AGE OR OLDER
SALE TO PERSONS UNDER 18 YEARS OF AGE IS PROHIBITED BY FEDERAL LAW
Other places on their website they refer to their different sized motors as high power motors. I don’t know why they’ve chosen to do this, but it’s their choice. Here’s their product webpage showing that they refer to all their motors as high power:
https://pro38.com/products.php
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CTI instructions are what make the balance also handled as HPR in the US AFAICT.
Possibly board(s) level reminders need to be exchanged e.g. UKRA/CAR/NAR/TRA such that CTI can get updated instructions in place so their little stuff can fly from the up-close.
As it stands now, I personally would not feel comfortable authorizing any CTI on the model pads at most organized launches.
Possibly board(s) level reminders need to be exchanged e.g. UKRA/CAR/NAR/TRA such that CTI can get updated instructions in place so their little stuff can fly from the up-close.
As it stands now, I personally would not feel comfortable authorizing any CTI on the model pads at most organized launches.
Exactly, and I sent a note to CTI.
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The nuance is that CTI labels them as high power motors on their website and in their instructions. I don’t know why. Otherwise I would agree with you.
boatgeek
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I now have lots of questions. And I'm going to stop asking because I don't want them answered.
I now have lots of questions. And I'm going to stop asking because I don't want them answered.
I understand. Feel free to pm me if you want.
heada
Well-Known Member
If the regulations say it isn't HPR but the manufacturer labels it as HPR, what is it? If Estes decides to label the C6-5 as HPR, does that make it HPR?
A literal interpretation of NFPA 1125 would suggest so.
We’re required to follow the instructions packaged with a motor, right?
So CTI includes this text at the beginning of their instructions:
FOR USE ONLY BY CERTIFIED HIGH-POWER ROCKETRY USERS 18 YEARS OF AGE OR OLDER
SALE TO PERSONS UNDER 18 YEARS OF AGE IS PROHIBITED BY FEDERAL LAW.
Do we simply ignore that? I don’t know why they added it.
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So 18+ L1 Certed authorizes the user ; and the standoff distance gives the spacing.
I haven't studied all the text(s) in detail but the way I now read it is " kids + CTI = no ", not "model pads + CTI = no"
I haven't studied all the text(s) in detail but the way I now read it is " kids + CTI = no ", not "model pads + CTI = no"
That is how I would interpret it also. I think it’s possibly a mistake on CTI’s part.
Certified motors come in two classes: model rocket motors and HPR motors. Model rocket motors come in two subclasses: those that anybody can use and those limited to ages 18 and above.
With the exception of sparkies I think most of CTI’s under H motors would fit in the model rocket motors with some for sale to adults only. I just don’t understand why they labeled them the way they did.
