Is it normal for a motor liner to shrink and deform?

[billdz]

Saturday I launched a Darkstar Jr to 9019' at Mach 1.24, new personal altitude and speed records. It was a perfect flight, no issues at all. The motor was a CTI 38mm J530 in a 6XL case. When we removed the case from the rocket to clean it, we noticed that the liner had shrunk and was deformed, see below pic. Is this normal? I've launched several CTI motors before but this was my first 6XL. All other times the liner looked the same as before the flight, no shrinkage or deformity.

Thanks,
Bill

 

[cavecentral]

I do not fly cti much, but seen this deformation on many 29mm friends flew. I'd say no burn through, no problem.

 

[Bat-mite]

Mine often get melty, but I have never seen one shrink like that! Could the mach transition have something to do with it?

 

[tim cubbedge]

Yes normal to deform but never saw one shrink like that. Was there a spacer in it?

 

[mpitfield]

I have had several spent reloads come out of the hardware like that, all nominal flights.

 

[billdz]

No spacer, thanks for the replies.

 

[Kallahan11]

My 38 6xl reloads come out looking like that too.

 

[billdz]

Thanks for the replies, seems like nothing to worry about.

 

[crossfire]

Thanks for the replies, seems like nothing to worry about.

Yes its normal. Jeron from CTI told me most of it takes place after motor burn out.

 

[blackjack2564]

Top gets fried from the 14 second smoke grain burn.

 

[3stoogesrocketry]

Top gets fried from the 14 second smoke grain burn.

Ive also seem this exact same thing happen on motors that shut off real quick . Im thinking there might be a vacume pulled that sucks the liner down . I may be wrong .

Eric

 

[Andrew_ASC]

Seen the CTI 29MM H motors deform liners like that. Seems normal for CTI stuff. My Aerotech liners never do that, but... If you forget a liner in an Aerotech casing you'll never fly that casing again is the story. Never had that happen, but other wise people had good advice.