I still have some of those long 18mm AVI D6.1's.
Have not flown one in probably 25 years.
Those worked well back in the day for light rockets.
Would only be interested in long 18mm SU motors if they serve a unique niche such as a REAL PORT BURNER with some actual KICK. Like a D20 or E25.
As soon as Estes releases the new C5 and B8 motors, I'm buying a boatload of them to stockpile so when they discontinue them again I won't be sorry.
What they really should do is replace the entire B6 series with the B8. The B4 and B8 lines would be plenty if they brought back the B4-6.
Totally replace the C6-3 and C6-0 with the C5-3 and C5-0.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC !