Quantcast

CTI H163 question

The Rocketry Forum

Help Support The Rocketry Forum:

qquake2k

Captain Low-N-Slow
Joined
Jan 26, 2010
Messages
13,573
Reaction score
35
Has anybody ever seem this? I last flew my Binary Effusion on a pair of CTI H163 White Thunders. I just pulled the cases out, and noticed that one motor is much shorter than the other. It looks like it shrunk. I've never seen that before.

H163_01.jpg


H163_03.jpg


P1100217.JPG
 

markkoelsch

Well-Known Member
Joined
Mar 18, 2009
Messages
4,364
Reaction score
148
Were they the same length when assembled? Only trying to eliminate a mislabeling issue.
 

CzTeacherMan

Well-Known Member
Joined
Aug 8, 2014
Messages
2,982
Reaction score
169
Yes. Happens quite often to CTI loads. As they burn, the liner melts and shrinks. Sometimes it happens more than others. Just depends on the motor itself and how it burns. No big deal.
Nice pic, by the way!
 

crossfire

Lifetime Supporter
TRF Lifetime Supporter
Joined
Jan 16, 2011
Messages
4,537
Reaction score
537
Jeron from CTI told me most of the melting and shrinking of the liner happens after motor burn out. Case is heated up as motor burns. As long as the case has no damage the liner did its job.
 

GRIFFIN

Well-Known Member
Joined
Aug 25, 2009
Messages
3,208
Reaction score
92
Like Erik said. This is 100% normal. The liners get soft and start to melt. When the motor shuts down, there is a vacuum effect on the case and the pressure change pulls the front of the liner down towards the aft.

I used to think this was from the ejection charge pushing on the liner. The differential pressure thing was told to me by Dr. J.

No worries, throw them away and burn another one.

And Mark, no way would the motor even have worked if it were the wrong motor for the case.
 

Zeus-cat

Well-Known Member
Joined
Mar 14, 2009
Messages
4,592
Reaction score
797
So to quote George Costanza, "Yes. Significant shrinkage!"
 

crossfire

Lifetime Supporter
TRF Lifetime Supporter
Joined
Jan 16, 2011
Messages
4,537
Reaction score
537
Jason. I once flew a two grain motor in a three casa and forgot to put in a spacer it worked pefect. I got lucky
 

watermelonman

Well-Known Member
Joined
Sep 22, 2014
Messages
2,597
Reaction score
8
I used to think this was from the ejection charge pushing on the liner. The differential pressure thing was told to me by Dr. J.
Hah, I thought exactly the same until reading this today.
 

qquake2k

Captain Low-N-Slow
Joined
Jan 26, 2010
Messages
13,573
Reaction score
35
Thanks for the replies, guys. Never happened to me before, I thought it was odd.
 

qquake2k

Captain Low-N-Slow
Joined
Jan 26, 2010
Messages
13,573
Reaction score
35
Jeron from CTI told me most of the melting and shrinking of the liner happens after motor burn out. Case is heated up as motor burns. As long as the case has no damage the liner did its job.
How is Jeron doing? Didn't he get burned in the CTI fire?
 
Top