Results 1 to 20 of 20

Thread: Can lift struts be straightened?

  1. #1
    supercub's Avatar
    Join Date
    Apr 2002
    Location
    Let me check my GPS, gee how'd we ever navigate with those sectional things?
    Posts
    863
    Post Thanks / Like

    Can lift struts be straightened?

    I have a a front and rear sealed lift strut for a J-3 Cub that have slight bows in them, absolutely NO crease at all. Can these be straightened? If so, is there someone that specializes in doing this, or how does one go about doing it. I haven' measured them yet, but I'm think there's only about an inch or so off set from one end to the other. Thanks
    Last edited by supercub; 04-29-2018 at 12:05 PM.

  2. #2

    Join Date
    Jan 2007
    Posts
    2,240
    Post Thanks / Like
    They will straighten pretty easy, this is not a huge force type of job. If it was mine, I would lay them on flat table/floor with the bow up. Find highest part of bow and put tape to make it. Most bows are not in center of the strut, so measure out from the tape to the closest end. Now put a 1-2 inch padded block under one end and another at the same distance from the tape under the strut. Very push down at the center of the bow it should bend back pretty easy. Take your time and check your progress several times, you will have to go past straight due to spring back that is the reason for the blocks. Pretty easy to make a single bow into a S bend if you get in a hurry. Two experienced guys and a saw horse can do it in a few min. The trick is to find the apex of the bow and support equal distance form that as you straighten. Others may have different advice mine is worth what ya paid for it.
    DENNY
    Thanks Bommer, barrow pilot thanked for this post
    Likes barrow pilot liked this post

  3. #3

    Join Date
    Sep 2003
    Posts
    7,334
    Post Thanks / Like
    If the bow is slight, and centered, the jury struts are enough. If it is not centered, that may mean metal has been stretched. That is more of a problem, structurally.
    Likes cubpilot2, DENNY, barrow pilot liked this post

  4. #4
    n40ff's Avatar
    Join Date
    Oct 2009
    Location
    WV
    Posts
    986
    Post Thanks / Like
    How do they get bent in the first place?

  5. #5
    supercub's Avatar
    Join Date
    Apr 2002
    Location
    Let me check my GPS, gee how'd we ever navigate with those sectional things?
    Posts
    863
    Post Thanks / Like
    Quote Originally Posted by n40ff View Post
    How do they get bent in the first place?
    I have no idea, I bought the project and they were that way.

  6. #6
    n40ff's Avatar
    Join Date
    Oct 2009
    Location
    WV
    Posts
    986
    Post Thanks / Like
    An outside loop pulled a bit hard

  7. #7
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    11,758
    Post Thanks / Like
    depending on WHERE the bend is on struts, you may need to check forks for damage, and or STRAITEN the strut attach fitting on fuselage(they get bent) big crescent wrench.... it will bow struts if misaligned

  8. #8
    Cub Special Ed's Avatar
    Join Date
    Oct 2016
    Location
    MT/SD
    Posts
    543
    Post Thanks / Like
    Flip them over? Repeat menuever that caused the first bends?

  9. #9
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    10,861
    Post Thanks / Like
    Are these struts bowed fore and aft or up and down?

    If fore and aft the bend may have been caused by improperly pushing the airplane. Pushing the plane by grabbing the middle of the struts is a no-no. I know, it is done all the time. Sometimes it can be done safely, other times watch out.

    If up and down someone may have lifted the plane with the struts or perhaps the fuselage attach fitting has somehow become bent in which case the forks are being subject to improper forces.
    N1PA
    Thanks barrow pilot thanked for this post
    Likes jonasw19, barrow pilot liked this post

  10. #10
    Steve Pierce's Avatar
    Join Date
    Mar 2002
    Location
    Graham, TX
    Posts
    20,384
    Post Thanks / Like
    I have seen bowed struts with no kinks and just a slight bow. The struts are mild steel. Support eack end and push in the middle and see what happens, you got nothing to loose. I tried it, didn't kink but looked like a wet noodle with the bow going both up and down. It now lays in the scrap heep beside my hanger.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  11. #11
    cubdriver2's Avatar
    Join Date
    Apr 2003
    Location
    upstate NY
    Posts
    10,407
    Post Thanks / Like
    If you fly skis the back ones are going to get bent anyway

    Glenn
    "Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"
    Likes BC12D-4-85 liked this post

  12. #12

    Join Date
    May 2017
    Posts
    806
    Post Thanks / Like
    Years ago while glider towing in a PA-18A-150, glider released and I did my “normal” left turn continuing into a split S. On the recovery, I hit one hell of a bump, and the jury strut clamp slid up the rear strut a ways, leaving a big bow in that strut. Needless to say the rest of the flight was very docile with gentle turns and low airspeed. On the ground, careful inspection of the strut fork, move the clamp back into position which straightened the strut. Investigate why the clamp moved and made appropriate corrections. The airplane is still happily towing gliders today with the same struts installed some 30 or 40 years later.


    Sent from my iPhone using Tapatalk
    Likes DENNY liked this post

  13. #13
    Kodiakmack's Avatar
    Join Date
    Sep 2020
    Location
    winters in Utah, Summers in Idaho
    Posts
    90
    Post Thanks / Like
    I also have a mild bow in my rear lift struts. Plane flies straight as an arrow. Any problem with leaving this or need to try and straighten?
    HAVE FUN. DON'T DIE.

  14. #14
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    11,758
    Post Thanks / Like
    Quote Originally Posted by Kodiakmack View Post
    I also have a mild bow in my rear lift struts. Plane flies straight as an arrow. Any problem with leaving this or need to try and straighten?
    Is it a bow in strut or A BOW CAUSED BY BENT LOWER ATTACH FITTING??? Big crescent wrench will correct the fitting angle.

    Where is the bow? Above or below jury struts??

    Are jury struts and clamps incorrect position??

    Jury struts are 2 different lengths per side....


    Sent from my iPhone using SuperCub.Org mobile app

  15. #15
    Kodiakmack's Avatar
    Join Date
    Sep 2020
    Location
    winters in Utah, Summers in Idaho
    Posts
    90
    Post Thanks / Like
    I’ll have my IA look at it on inspection. He maintained several cubs for the state of Utah and will know the cause. Sounds like the answer is not to just leave them.
    HAVE FUN. DON'T DIE.

  16. #16
    windy's Avatar
    Join Date
    Dec 2005
    Location
    Utah
    Posts
    725
    Post Thanks / Like
    Quote Originally Posted by Kodiakmack View Post
    I’ll have my IA look at it on inspection. He maintained several cubs for the state of Utah and will know the cause. Sounds like the answer is not to just leave them.
    Curious, who is your mechanic?

  17. #17
    Kodiakmack's Avatar
    Join Date
    Sep 2020
    Location
    winters in Utah, Summers in Idaho
    Posts
    90
    Post Thanks / Like
    My mechanic is my Dad. My IA is Mike Vandehei
    HAVE FUN. DON'T DIE.
    Thanks windy thanked for this post

  18. #18
    Kodiakmack's Avatar
    Join Date
    Sep 2020
    Location
    winters in Utah, Summers in Idaho
    Posts
    90
    Post Thanks / Like
    Windy, we’ve met a long time ago. You know my dad’s friend Claude.
    HAVE FUN. DON'T DIE.
    Thanks windy thanked for this post

  19. #19
    Steve Pierce's Avatar
    Join Date
    Mar 2002
    Location
    Graham, TX
    Posts
    20,384
    Post Thanks / Like
    Rigging of the struts has you adjust the jury struts so the wing struts are straight. Had a customer ask me why his jury struts weren't aligned once and showed him it was to make the wing lift struts straight.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers
    Likes dgapilot liked this post

  20. #20
    Crash, Jr.'s Avatar
    Join Date
    May 2015
    Location
    Anchorage, AK
    Posts
    354
    Post Thanks / Like
    The short answer is that yes, you can straighten struts. It's done all the time by laying them on a set of sawhorses and gently pushing down against the bow to get them straight.

    Like others have said though if the bow was induced by something in your rigging, that should be addressed.
    Thanks barrow pilot thanked for this post

Similar Threads

  1. Want used J3 Lift struts...
    By CptKelly in forum Cafe Supercub
    Replies: 2
    Last Post: 04-12-2007, 10:21 PM
  2. lift struts
    By fernandonunez in forum Cafe Supercub
    Replies: 4
    Last Post: 04-12-2007, 08:30 PM
  3. Lift struts
    By Marc Olson in forum Super Cub Sick Bay
    Replies: 4
    Last Post: 05-31-2005, 04:17 PM

Bookmarks

Bookmarks

Posting Permissions

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