Why are some G reloads considered HPR L-1 reloads?

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Andrew_ASC

UTC SEDS 2017 3rd/ SEDS 2018 1st
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In order to certify L-1 I understand I need a H to I motor of 160.01Ns or greater to 640Ns. '

This CTI 6G reload 24mm is 143Ns, yet to buy it from a vendor requires an L-1.

https://www.apogeerockets.com/Rocke...Grain_Motors/Cesaroni_P24-6G_Blue_Streak_G150

Is there a lower limit cutoff of Ns for an L-1 reload outside of the certification range?

This G-65 is 144Ns and is not an L-1 required to purchase motor. How does an MPR motor have more Ns than an HPR motor and still stay MPR?

https://www.apogeerockets.com/Rocke...ain_Motors/Cesaroni_P24-6G_White_Longburn_G65

Does anybody got an answer? I find this perplexing to say the least.
 
Any motor with a average thrust over 80Ns is considered HP. All motors that are are sparkies also HP.


Where Is The Line Between Model and High Power Rocketry?

A rocket exceeds the definition of a model rocket under NFPA 1122 and becomes a High Power rocket under NFPA 1127 if it:

Uses a motor with more than 160 Newton-seconds of total impulse (an “H” motor or larger) or multiple motors that all together exceed 320 Newton-seconds;
Uses a motor with more than 80 Newtons average thrust (see rocket motor coding);
Exceeds 125 grams of propellant;
Uses a hybrid motor or a motor designed to emit sparks;
Weighs more than 1,500 grams including motor(s); or
Includes any airframe parts of ductile metal.

In addition, a rocket exceeds the definition of a model rocket under FAA rules (FAR 101.22) if weighs more than 1500 grams (53 ounces).
 
So. The G65 is 144Ns specific impulse and not HPR. The thrust is 159.7 Newton. I do not understand this. The G150 at 143 Ns is 247.4 Newton of thrust.

Is there a thrust limit on this also???? Because your 80Ns rule of thumb isn't accurate in this one case. Otherwise I would need an L-1 certification to buy a G65 since it exceeded 80Ns by that logic. So somehow these motors got certified as HPR reloads, then this other one didn't. And I don't get the logic behind it okay...
 
You are confusing total impulse with thrust. The G 150 has an average thrust of 150N. almost double the 80N. , and a total impulse of 143Ns.

Sorry with the confusion with the Ns N's N .
 
As an aside... I know you are dealing with US regs here.

You’d think that rather than the average you’d go with total impulse instead?

When the Canadian Federal Government looked at the US rules they took the total impulse as the benchmark as opposed to the average making a G entirely mid power. Anything greater than 160 Ns in totality is high power and requires authorization to launch -


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As an aside... I know you are dealing with US regs here.

You’d think that rather than the average you’d go with total impulse instead?

When the Canadian Federal Government looked at the US rules they took the total impulse as the benchmark as opposed to the average making a G entirely mid power. Anything greater than 160 Ns in totality is high power and requires authorization to launch -


Sent from my iPhone using Rocketry Forum

Side Quest:
Here in the US there are some H motors (L1) that require certification to buy/fly, but contain under 150g propellant and are able to be flown in class 1 rockets (without a waiver).

Does Canada also have this allowance, or do all HPR (H, L1 etc...) require a waiver?
 
Canadian rules:

All motors greater than 160 Ns or having a total combined impulse of 160 Ns require certification / waver for flight regardless of altitude. The same is for a rocket that is 1500 grams of weight or greater - it also requires a waver and comes under certification rules. I fly 159G125 CTi loads with my students for our supersonic rocket flights. No need for any waver - just fire/LEA on standby in case of an issue. Last attempt we hit Mach 1.35 @ 5436 feet - the biggest issue is usable space.


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Thank you.

That makes complete sense. I wonder how the impulse level got left out of the class 2 criteria on our side of the border.
 
Don’t know. I prefer to have simpler rules to follow.

But US does have more choice in product and places to launch from.
 
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