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Old 01-18-2020, 06:38 PM
Vanel Vanel is offline
Master Modeler
Join Date: Jun 2005
Posts: 735

Originally Posted by astronwolf
It's not conjecture. NAR and FAI contest fliers have tested motors on test stands over the years, and that's where our anecdotal information comes from. But no one has published the data AFAIK.

This is interesting - I have a test stand I put together using equipment from Vernier, and have used it to successfully test a few motors. So I went to my motor stash and pulled out the following B6-4's:

Date code Weight (grams)
8 12 69 16.59 (also has a greater nozzle diameter)
17F5 (5/17/75) 18.23
19K5 (5/19/80) 17.81
15W5 (5/15/92) 18.36
A052703 (5/27/03) 17.76
B180918 (9/18/18) 19.00

I have dug out the test equipment and hope to do the tests this coming weekend, weather permitting. I then will post the thrust curves for scrutiny.

The attached shows a nozzle comparison, with the 1969 B6-4 on the left.
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Bill Cooke
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Huntsville, AL

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