Aerotech G79W vs Aerotech G64W reloads

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solid_fuel

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Other than the difference in average thrust how much different are these two loads? they both seem to have similar total thrust with 112ns total the other with 115 total. looking at the curves the 64 has a higher initial thrust and drops off while the 79 stays pretty flat like a plateau. the 64 has a much longer burn time though at almost 2.5 seconds vs the 79 at barely over a second. help a new guy interpret this data and please correct any mistakes. thanks

Andrew
 
For starters these go in different hardware. The thrust curve for the G64 you're looking at is almost certainly the old single-grain version, not the current USPS-shippable two-grain version. That said, yes, the G64 has slightly lower average thrust and slightly longer burn time (the G79 is a BATES grain and the G64 is a C-slot.)
 
got ya on different hardware. And yes you're right I went back and looked at the PDF of Aerotech catalog I got the information from and copyright date is 2009 so that is probably old data. do you know where I can see the current thrust curves for these?
 
You can find current data from the NAR on this website:
https://www.nar.org/standards-and-testing-committee/nar-certified-motors/

The G79W reload was TRA certified.

https://www.nar.org/SandT/pdf/CombinedMotorsByImpulse.pdf
https://www.nar.org/SandT/pdf/Aerotech/G64.pdf

And, of course, I see an error on the "combined" PDF list of certified motors as well as the old data sheet on the main NAR list page. They still list the G64 as the original single piece grain 62.5 gram propellant version with 120 N-s total impulse. it is now "bifurcated" with two 30 gram propellant grains and only 115 N-s total impulse. Aerotech has the correct data on their website:
https://www.aerotech-rocketry.com/c...tions/RMS-29_40-120/rms_29_g64_bif_20032b.pdf
 
It's mostly a question of hardware choice (the G79 is available in a single-use form also.)

That's correct, in both a HAZMAT version and USPS Mailable version (the "LMS").
 
For me, the RMS 29/120 hardware is a easier to assemble/disassemble than the 29/40-120, and the large core is easier to insert an igniter in. The G64 reloads are a bit lower cost, though.
 
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