gap in K300

[watermelonman]

I assembled a K300 and the massive single grain is free to slide about a half an inch between the nozzle and forward closure.

Is that normal? It sure seems weird to me.

 

[tfish]

https://www.rocketryforum.com/showthread.php?66659-CTI-K300&p=719833#post719833

Tony

 

[watermelonman]

Aha! I did search but missed that one. Thanks for the pointer.

Mine does not appear to include the insert that message refers to.

 

[CzTeacherMan]

Mine had that same slide... It's normal. Flew my 3"DarkoStar to just over 12,000'

 

[watermelonman]

Did you make any effort to restrain it?

I wonder where the slug sits in the liner, during the burn, unrestrained. Probably at the bottom since it started there during pressurization, but still curious.

 

[CzTeacherMan]

Did you make any effort to restrain it?

I wonder where the slug sits in the liner, during the burn, unrestrained. Probably at the bottom since it started there during pressurization, but still curious.

Nope. Just left it as is. Doesn't matter where in the liner it sits because even if it moves, it moves together. Burning surface area doesn't change as it would in a motor with several loose grains.
Quick tip... That ignitor is a real pain to insert... The slotted core doesn't exactly give you a lot of room to insert the globby ignitor.