Average thrust limit?

I seem to recall reading in Stine’s Handbook of Model Rocketry that the average thrust of a model rocket motor (as opposed to a high-power rocket motor) is limited to 80 Newtons. Looking at sources from AeroTech however, it appears that there are several G motors available that exceed this and don’t have a requirement for an L1 certification, like the G104T, G125T, and G339N.

The only G motors ones I see that require it are the G75M, presumably for using the sparky Metalstorm propellant, and the G138T, for reasons I can’t seem to identify.

So what exactly are the criteria for classification as a model rocket motor vs a high-power one? It seems that some of the G motors available are classified arbitrarily.

smstachwick said:

Looking at sources from AeroTech however, it appears that there are several G motors available that exceed this and don’t have a requirement for an L1 certification, like the G104T, G125T, and G339N.

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An L1 is required to purchase these three. Check dealers such as csrocketry or apogee and you will see it is a requirement.

Titan II said:

According to their website, an L1 is required to purchase these three.

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Interesting. I should have dug a little deeper, Apogee says the same thing about the reload kits in their store.

Looks like some sloppy research on my part. Note to self: Check the Motor Matrix AND the other parts of the site before posing a question to the forum.

If you like pictgraphs, this document has it all:

Thank you! That was my understanding of the MPR/HPR threshold, looks like I just came across some inaccurate data and failed to cross-check it.

Nice graphics, too. Where did you find this?

smstachwick said:

Thank you! That was my understanding of the MPR/HPR threshold, looks like I just came across some inaccurate data and failed to cross-check it.

Nice graphics, too. Where did you find this?

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It was created by our friend Doug Sams many moons ago; I believe at the request of one of our vendors, PML. It can be be found on Southern Area Rocketry's resources page:

https://www.soarrocketry.org/wp-content/uploads/2016/08/HPR_metric9c.pdf