Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Page 1 of 2 12 LastLast
Results 1 to 10 of 19

Thread: Extra wing rib braces?

  1. #1

    Join Date
    May 2014
    Location
    Tulsa, Oklahoma
    Posts
    4

    Default Extra wing rib braces?

    Hello fellow aviation enthusiasts,
    I have thoroughly enjoyed reading many of the helpful solutions and encouragements.
    I have purchased a KF4-1050 last year. The wings and airframe were already covered and painted, no engine. The wings have 13 gallon tanks. Upon closer inspection of the wings, noticed extra braces installed on the fwd part, inbd/otbd sides of all the wing ribs and attached to the fwd spar with 1/8x3/8 rivets. Each support bracket on the fwd spar has been attached with two rivets.All these extra supports are not depicted on the wing assembly instructions.
    1. I'd like to know if this has been accomplished on any KF4 for starters.
    2. If I conform my wings to the drawing as depicted, would there be any problem using universal cherry max rivets to plug all 1/8 holes on the fwd spar?
    3.Should the fwd spars be replaced or leave the additional braces?
    All the green lines drawn on the diagram, represent the extra braces installed. The other diag shows dimensions of the braces which was to be installed only on the #10 wing rib.

    Looking fwd to all your insight,
    JC
    Attached Images Attached Images

  2. #2
    Senior Member jiott's Avatar
    Join Date
    Jun 2010
    Location
    Portland, OR
    Posts
    2,959

    Default Re: Extra wing rib braces?

    Wow! I see no point in those extra braces. All they do is stabilize the ribs, which in my opinion needs no more stabilization due to the main spar cross braces that pass thru and are glued to the ribs near the point where all those extra braces are. The ribs are not really much of a structural part of the wing; all they do is serve to hold the fabric in the proper airfoil shape and hold the trailing edge. The structural part of the wing is the spars and the cross brace/drag tubes. Seems to me that those extra braces are just added weight.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

  3. #3
    Senior Member HighWing's Avatar
    Join Date
    May 2009
    Location
    Goodyear, AZ
    Posts
    1,743

    Default Re: Extra wing rib braces?

    My thinking is that since the holes were drilled for the extra bracing on the lateral side of the spar - similar to the shear web on a rib, it likely doesn't weaken the spar significantly. That being said, however, I would't feel comfortable if my name was on the Airworthiness Certificate as the "Manufacturer" and therefore legally responsible for the final design and assembly. Thinking down the future, my main concern would be for you to consider how comfortable you would be selling it as a flying airplane as it is currently assembled when and if that time comes.
    Lowell Fitt
    Goodyear, AZ


    My You Tube Channel

  4. #4

    Join Date
    May 2014
    Location
    Tulsa, Oklahoma
    Posts
    4

    Default Re: Extra wing rib braces?

    There's about a 10inch gap between each brace attached to the spar as seen from the wing tip. I'll be opening the wing this weekend for a structures technician to give me his final say.
    Thank you so much for your valued opinion.

  5. #5
    Senior Member
    Join Date
    Apr 2009
    Location
    Chisholm Mn
    Posts
    1,562

    Default Re: Extra wing rib braces?

    I typed this a few days ago, and then didn't hit the submit reply button, but maybe will now. There have been thousands of these wings built and flown at various weights between Avid Flyers and Kitfoxes, not to mention the other designs that also are copies of them in one form or another.
    In fact clear up to 1500 lbs. or more.
    That's about1/3 more weight then your 1050 gross weight. I don't believe there were any wings falling apart in the sky. Why do people think they need to improve on an already proven design. JImChuk

  6. #6

    Join Date
    May 2014
    Location
    Tulsa, Oklahoma
    Posts
    4

    Default Re: Extra wing rib braces?

    I don't understand why people think they need to add to a proven design. It was pretty disappointing realizing all these braces were not on the manufacturer drawing.
    Thanks for ur post.....

  7. #7
    Guy Buchanan's Avatar
    Join Date
    Mar 2009
    Location
    Ramona, CA
    Posts
    119

    Default Re: Extra wing rib braces?

    1. Not here.
    2. Your question is a little confusing, but the only problem with filling holes would be if the rivets were stainless and caused corrosion. Alu rivets would be fine, but in my opinion unnecessary for two 1/8" holes in a 3" tube along its shear center.
    3. The wings are covered satisfactorily? I'd leave them. The weight's not worth the hassle and otherwise I can't see a detriment.
    Guy Buchanan
    San Diego, CA
    Deceased K-IV 1200 / 912uls / 70" Warp 3cs

    gebuchanan@cox.net

  8. #8
    Senior Member
    Join Date
    Apr 2009
    Location
    Chisholm Mn
    Posts
    1,562

    Default Re: Extra wing rib braces?

    Guy, did you mean steel rivets causing corrosion? I don't think SS rivets cause corrosion to aluminum. That is what Kitfox supplies for riveting all the pieces to the spars. (I didn't want Johnny worrying about corrosion as well) JImChuk

  9. #9
    Guy Buchanan's Avatar
    Join Date
    Mar 2009
    Location
    Ramona, CA
    Posts
    119

    Default Re: Extra wing rib braces?

    Well, any time you put stainless and aluminum together you get electrolytic corrosion, particularly if you're in a humid or marine environment.

    More than you ever wanted to know.
    Guy Buchanan
    San Diego, CA
    Deceased K-IV 1200 / 912uls / 70" Warp 3cs

    gebuchanan@cox.net

  10. #10

    Join Date
    May 2014
    Location
    Tulsa, Oklahoma
    Posts
    4

    Default Re: Extra wing rib braces?

    The wing coverings are fantastic. I get the dissimilar metal issues. Already added additional inspection holes for my structural technician to inspect the spar. After the braces are removed from the wing ribs, those areas will be inspected and reinforced per the AC43.13-1B.
    My thoughts for removing the braces.
    1. Not on the original drawing
    2. Possibility of a future problem due to vibration where the added braces attached to the wing spars.
    Over kill? Probability, but I'm thankful for this forum and all your replies.

Posting Permissions

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