Lightning Build
#63
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Now, on to the task of sheeting the bottom of the fuselage. This is more complicated that sheeting the top as the curves are more complex. In order to make it manageable, I am sheeting it in four sections. I don't have a good shape pre-mold like I did for the turtle deck sheeting, so it is all done on the fuselage. To keep it from getting waves, I only wet the inside of the wood, and I use balsa sticks pinned along the edges to keep them straight. When I tape the sheets to the fuselage, I only wrap it around where the formers are to prevent waves. I shape the edges of the wood prior to wetting, much easier to sand!
Here are pictures of the first two sections on the fuselage for molding, and after they dried and were removed.
Here are pictures of the first two sections on the fuselage for molding, and after they dried and were removed.
#65
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Now that the first sections are formed, it is time to glue them on.
Here is a little trick with Gorilla Glue that I can't believe I didn't think of earlier. I used a syringe for glue for application which made it much easier than trying to use the bottle and sticks to spread the glue. I was able to use much less glue as I could apply it exactly where I wanted it. The syringe cleaned up with alcohol so I can re-use it.
I placed the seam along one of the stringers to help keep the edge of the sheeting straight.
Here is a little trick with Gorilla Glue that I can't believe I didn't think of earlier. I used a syringe for glue for application which made it much easier than trying to use the bottle and sticks to spread the glue. I was able to use much less glue as I could apply it exactly where I wanted it. The syringe cleaned up with alcohol so I can re-use it.
I placed the seam along one of the stringers to help keep the edge of the sheeting straight.
#67
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Anthony,
When I finished gluing, I squeezed as much glue out of the syringe as I could. Then I filled a bottle cap with denatured alcohol and filled and evacuated the syringe multiple times, which got most of it. To get the gunk out of the tip, I used a scrap of 1/8" square balsa stick, with a slightly sharpend tip. I stuck it through the back of the syringe and twisted it to bring out the remaining glue. Then I swished more clean alcohol through it. That left it clean enough for further use.
When I finished gluing, I squeezed as much glue out of the syringe as I could. Then I filled a bottle cap with denatured alcohol and filled and evacuated the syringe multiple times, which got most of it. To get the gunk out of the tip, I used a scrap of 1/8" square balsa stick, with a slightly sharpend tip. I stuck it through the back of the syringe and twisted it to bring out the remaining glue. Then I swished more clean alcohol through it. That left it clean enough for further use.
#68
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Section three and four of the bottom sheeting are molded in the same manner as the first two. Balsa holds shape very well once it is dry. Once I removed the dry sections from the fuselage, I trimmed the edges to make nice seams. This is difficult as prior to having the sheeting glued on, the stringers and formers have a bit of flex. As you try to hold the parts into their final position to test the fit, you distort the structure with the pressure of holding them in place. It may look beautiful has you hold everything together, but when you take your hand away, everthing springs back into place and your seams open up. This is exactly why I keep large tubs of filler on hand.
Electrical tape was not required at the balsa sticks I used to hold the edges down while gluing are covered with a layer of clear packing tape. Easy mold release! The syringe technique also made for much cleaner seams.
Electrical tape was not required at the balsa sticks I used to hold the edges down while gluing are covered with a layer of clear packing tape. Easy mold release! The syringe technique also made for much cleaner seams.
#69
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I have finally cleared out a mountain of blue painter's tape in my garage to reveal a 99% complete fuselage. The only steps remaining are to install the wing and stab sockets, and then sand to final shape. Also, I left the sheeting off of the bottom of the subfin area to allow access to the stab socket. Once the socket is glued in, that area will be sheeted. Right now, the fuselage weighs in at 20.8 oz. For comparison, the prototype weighed 28 oz at the same stage. Now, on to wings and stab.
#73

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Joined: Aug 2004
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From: San Antonio,
TX
Take your time remembering unless you are going to fly FAI 
Jeff,
I remember the masters finals a few years ago, it wont take you long to return to that form!
Hope to see you are the field,
Chuck

Jeff,
I remember the masters finals a few years ago, it wont take you long to return to that form!
Hope to see you are the field,
Chuck
#75
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On to the wings. They are more or less conventional foam and balsa wings. I do use some strips of carbon fiber for reinforcement. I had the cores cut by Mark Hunt, Insight RC. The unique thing about the way Mark does wings and stabs is his "honeycomb" method. He drills a grid of 1/4" holes rather than the traditional square pattern. I use a 1/8" lightply rib at the end of the wing socket. I also cut the holes for the aileron servos and install balsa boxes prior to sheeting. I made a tool out of 1/16" wire to cut the hole for the aileron servo leads. It is a simple loop that plugs into my soldering gun.


