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Carbon Fiber Gull Wing Doors

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  • Carbon Fiber Gull Wing Doors

    I completed these several months ago. The latching system and gas strut installation was another task that took way too much time. I built the frames from 20mm square carbon tubes. The frames by themselves weigh 3# each. That is a 6# savings each compared to building them from 3/4" steel tubing. I used the hinges that would have been used for the windows. To reinforce the attach points in the carbon fiber, I inserted 1" pieces of 5/8" square steel tube into the upper tube before connecting the tubes. I purchased Suspa gas tubes from Amazon to support the doors. 17" extended, 10 3/4" compressed. I initially used 20# struts that provided marginal support. One tube by itself would slowly collapse. Went with 28# struts that securely support the door. Hopefully will be able to taxi with the doors open. I used the Hendricks latches which are expensive but very well made. Figuring out the arrangement of the locking rods and levers took me a long time. I initially tried to locate the hole for the forward rod too high on the sheet metal former. It interfered with the vertical tube. My goal was to have the rods at 90 deg to the structure so the bushings would sit flat. It took me quite a while to realize that I could accomplish that by slightly bending the rods. Hendricks sells pre made rods and links. You need to make your own. I found the best price for the 3/8th aluminum rod and 1/2 x 1/8 aluminum bar at wicks. For closing the door I think a handle separate from the latch handle is needed. I couldn't find a suitable one so welded one from 3/8th steel tube. For the door trim, I laid up carbon fiber in place. It is one piece. It attaches with #8 screws through the trim, plexiglas and into drilled and tapped holes in the carbon fiber tubes. I learned that was possible from Mike Patey, initially thought I would need long screws through the tubes. Plexiglas is .100, think that will work with the cross tube providing additional support. Total weight of the doors is 9#. Would I recommend others build their windows, doors etc with carbon tubes. That's a definite no. While it was nice to save 12#s, the extra time and expense was not worth it. I am going to love the view out of the full plexiglas doors.

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  • #2
    Wow! Really nice work, Rod.
    Patrol QB #312
    Buchanan Airfield
    Concord, CA

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    • #3
      Hey Rod…that looks really nice for sure. My doors are heavy because of all that Lexan, but I’m happy they open/close and I’m moving on! In conversation with schu I found out the Hendricks keyed door lock doesn’t prevent someone from opening the locked door from the outside. All someone has to do is rotate the outside handle the opposite way and voila, the mechanism opens. I tried it and it did open even though it was locked. Schu welded a stop on his frame to keep it from rotating backwards. I was way too far along to do that so I made a stop out of AL angle and fastened it to the frame with a screw.

      homebuilt aircraft, builders log, experimental, experimental aircraft, 51% rule, fifty-one percent rule, 51% percent rule, aircraft homebuilt kit, aircraft homebuilt plan, aircraft composite homebuilt, aircraft experimental homebuilt, aircraft experimental kit


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      • rodsmith
        rodsmith commented
        Editing a comment
        Thanks for the heads up on the lock! Will have to see how I can fix that. The full view door does add more weight, but I think it is worth it.

    • #4
      Beautiful set of doors you have there Rod.
      Nev Bailey
      Christchurch, NZ

      BearhawkBlog.com - Safety & Maintenance Notes
      YouTube - Build and flying channel
      Builders Log - We build planes

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      • #5
        Wow those look nice. Thanks for taking the time to share.

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        • #6
          Great job on the doors, for reference my sea plane doors on the model five weigh 13 lbs. a piece. They have glass on the upper half and Hendricks handles.

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          • #7
            How much did you raise the lower door sill in order to get the necessary clearance from the wing strut when fully opened?

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            • #8
              Originally posted by Jhankins View Post
              How much did you raise the lower door sill in order to get the necessary clearance from the wing strut when fully opened?
              1 3/4". 1 1/2" would have worked and left a 1/2" for skin overlap below the door opening. Seems like most have raised the threshold 2 to 3". My fuselage is plans built but should have the same dimensions as the kits. You only have to raise the horizontal portion, not the angled.

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              • #9
                Originally posted by Jhankins View Post
                How much did you raise the lower door sill in order to get the necessary clearance from the wing strut when fully opened?
                FWIW, I raised mine two inches. I have 1/4in clearance between the strut and the door skin. The door skin extends 3/4in below the door frame.

                homebuilt aircraft, builders log, experimental, experimental aircraft, 51% rule, fifty-one percent rule, 51% percent rule, aircraft homebuilt kit, aircraft homebuilt plan, aircraft composite homebuilt, aircraft experimental homebuilt, aircraft experimental kit


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