SECTION 43: CABIN COVER

Build Instruction Updates

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Related Pages

• Door Seals

Posts

• FB 7/23
• VAF 5/21

Videos

• Craig's video
• BuildFlyGo's video 1
• BuildFlyGo's video 2
• A leaf on the Wind Videos
  • cabin top part 1
  • cabin top part 2
  • cabin top part 3
  • cabin top part 4

• Rodrigo Damazio Bovendorp' videos
  • Cabin Cover 1
  • Cabin Cover 2
  • Cabin Cover 3
  • Cabin Cover 4
  • Cabin Cover 5
  • Cabin Cover 6
  • Cabin Cover 7
  • Cabin Cover 8
  • Cabin Cover 9
  • Cabin Cover 10
  • Cabin Cover 11

Hints

• Fiberglass Dust Protection
  • 3M Respirator
  • coverall with hood
  • HobbyAir fresh air respirator (pumps clean air from remote location into mask). Full face mask also protects dust getting into your eyes / face.)

• (D. Peterson) This is time consuming, but it isn't rocket science. It is an expensive part & you don't want to mess it up, but be methodical & patient and it will be fine. We started with Dremels with Permagrit cutoff disks and also a Dewalt oscillating tool with a "fast wood" blade which worked surprisingly well (get a couple extra blades). I tried a jigsaw, but the blades I had dulled super fast. The 40 grit paper on a belt sander worked very well for the closer work and getting the bottom and sides of the door thin enough. We traced the scribe line with a fine tip sharpie and rough cut to that, then worked our way down until it fit. We probably put it on and off the airplane 15-20 times, which is a bit of a pain, but not bad in the big scheme of things. I now understand what people mean when they say it gets "razor thin"; the edges get very sharp as you get close to the end. Use caution! One thing we did wrong at first was trying fit the aft edge of the Upper Fwd Fuse OUTSIDE the cabin top. It doesn't work well that way. The skin goes INSIDE the cabin top. Seems obvious now. See pic. One thing we did toward the end of the door bottom was get a micrometer out and get average current readings, subtract 0.0625 (our goal of thinning for that round) so we had a goal to trim to. If you do this, mark your micrometer so you are sticking it "into" the cabin edge the same amount (the fiberglass tapers, so the depth of material into the throat of the micrometer affects your measurement). Before it got too thin we were drawing thin permanent marker lines to trim to. I second breathing protection, safety glasses, and hearing protection at least. We also used the air hose to blow ourselves off numerous times. Good luck. It took two of us about a day and a half. It wasn't as bad as I expected.
  
• There are several tools that work well for trimming fiberglass.
  • Vans ships a couple of cutting disks with the kit.
  • This combination is expensive but makes it really easy. The 60,000 rpm pencil grinder is very small and can rest on top of the surface. It grinds in all directions, meaning one can make an incision near the scribe line and slowly grind sideways until the scribe line is exactly matched, then cut forwards right along the scribe line. Makes cutting as easy as drawing a line.
    • Pencil grinder
    • Dremel Cutting / Shaping Wheel (You will need more than one)

Page 43-3

• Step 1:
  • The cover's scribe lines for where it needs to mate with the door opening of the fuselage are too far apart. The door opening is only 37 inches but the scribe lines yield a 37 7/16 wide cover. See this VAF thread for details. Consider making a tool to easily measure 1/8 thickness because that is about the final thickness the frame has around the door opening.
    
  • The scribe lines for the bottom of the door opening leave the cabin top too thick. The thickness should be determined by what is needed to have the cabin top joggle sit on the upper edge of the side skins. It will be about 1/8 thick as well.
  • The scribe lines for the windows are not giving you the requested 3/4 inch joggle, in some areas, only as little as 0.5 inch. Consider making your own scribe lines for the window cutouts.
  • The distance between the longeron and the upper edge of the outside skin is not necessarily 3/4 inches at all places. Measure and correct for your build. The scribe lines that Vans puts on the side lines are not correct (up to ~ 1 inch). Since the longeron is not necessarily parallel to the upper edge of the side skin, it's better to use the upper edge of the side skin and the upper end of the joggle on the cabin top as the two edges that need to match.
    
    The joggle is nominally 3/4 inch but will depend on the longeron to side skin top edge distance.
    
    Squaring the joggle step with a dremel set to 0.75 inches and the joggle depth.