Help Support RocketryForum by donating using the link above or becoming a Supporting Member.


Results 1 to 12 of 12
  1. #1
    Join Date
    11th February 2017
    Location
    south Florida
    Posts
    634

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

    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

    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	J530 liner after flight.jpg 
Views:	116 
Size:	48.5 KB 
ID:	333491  

    L1 3/25/17 H135 Wildman Darkstar Jr
    L2 8/12/17 J180 LOC Expediter
    L3 3/17/18 M1350 Painkiller Max

  2. #2
    Join Date
    1st July 2011
    Location
    Pittsburgh, PA
    Posts
    2,957
    I do not fly cti much, but seen this deformation on many 29mm friends flew. I'd say no burn through, no problem.

    Kevin Wuchevich
    Tripoli Pittsburgh
    TRA 12238

  3. #3
    Join Date
    5th December 2013
    Location
    MD
    Posts
    7,374
    Mine often get melty, but I have never seen one shrink like that! Could the mach transition have something to do with it?

    John S. ---- NAR #96911 ---- TRA #15253 ---- MDRA #067 ---- BARC #028
    L1, 3/15/14: Aerotech Sumo, CTI H133BS
    L2, 6/21/14: Giant Leap Vertical Assault, CTI J240RL
    L3, 3/12/16: MAC Performance Radial Flyer, CTI M1101WH
    Altitude: 13,028', L3 flight; Speed: Mach ???, L3 flight

  4. #4
    Join Date
    13th June 2014
    Location
    Cocoa Beach, FL
    Posts
    3,702
    Yes normal to deform but never saw one shrink like that. Was there a spacer in it?
    Tim
    L3 NAR 98225

  5. #5
    Join Date
    7th July 2013
    Location
    Toronto
    Posts
    3,548
    I have had several spent reloads come out of the hardware like that, all nominal flights.
    Michael Pitfield
    TRA 14579 L2
    NAPAS BoD
    URRG
    MARS
    CRC

  6. #6
    Join Date
    11th February 2017
    Location
    south Florida
    Posts
    634
    No spacer, thanks for the replies.

    L1 3/25/17 H135 Wildman Darkstar Jr
    L2 8/12/17 J180 LOC Expediter
    L3 3/17/18 M1350 Painkiller Max

  7. #7
    Join Date
    24th July 2016
    Location
    Grand Rapids, MI
    Posts
    199
    My 38 6xl reloads come out looking like that too.
    Level 1 - 4in cardboard Madcow Super Payloader DX3 - CTI 125 classic
    Level 2 - 4in cardboard Madcow Super Payloader DX3 modified for dual deploy - Aerotech J270 DMS
    Level 3 - 5.5in Fiberglass Madcow Super Payloader DX3 - Aerotech M1600 Red

  8. #8
    Join Date
    11th February 2017
    Location
    south Florida
    Posts
    634
    Thanks for the replies, seems like nothing to worry about.

    L1 3/25/17 H135 Wildman Darkstar Jr
    L2 8/12/17 J180 LOC Expediter
    L3 3/17/18 M1350 Painkiller Max

  9. #9
    Join Date
    17th January 2011
    Location
    Spring Green WI
    Posts
    2,792
    Quote Originally Posted by billdz View Post
    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.
    TRA 2225
    TWA
    QCRS
    WOOSH

  10. #10
    Join Date
    18th January 2009
    Location
    Savannnah, Ga
    Posts
    7,917
    Top gets fried from the 14 second smoke grain burn.
    Jim Hendricksen
    L-3 Tripoli 9693
    [ICBM, Orangeburg,SC R.I.P.] - QCRS ,Princeton ILL - MDRA , Price Maryland - Woosh, Bong Wisconsin- ROCC, Charlotte NC , ICBM Camden SC
    "Made" member of Chicago & Carolina Rocket Mafia
    Rocketry...........an exact science.......but not exactly !!!

  11. #11
    Join Date
    26th February 2012
    Location
    Poultney , Vt
    Posts
    941
    Quote Originally Posted by blackjack2564 View Post
    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
    You must always push your limits , because if you never fail , you will never succeed .

  12. #12
    Join Date
    22nd September 2017
    Location
    TN
    Posts
    994
    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.


Similar Threads

  1. [Wanted] Used Aerotech 54 mm motor grain liner
    By Kehoes23 in forum Yard Sale / Wanted
    Replies: 3
    Last Post: 16th June 2014, 11:33 PM
  2. Motor Liner burn thru
    By rabbitcreekrockets in forum Propulsion
    Replies: 6
    Last Post: 9th April 2014, 08:22 AM
  3. Pro38-6GXL Liner Ablation - Is This Normal?
    By WoShuGui in forum Propulsion
    Replies: 14
    Last Post: 13th November 2013, 08:45 PM
  4. Motor liner
    By north boy in forum Propulsion
    Replies: 28
    Last Post: 22nd August 2012, 05:31 PM
  5. J350 Motor liner
    By Brian62 in forum Propulsion
    Replies: 11
    Last Post: 18th September 2006, 08:57 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •