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General control line discussion => Open Forum => Topic started by: Allan Perret on July 23, 2011, 12:42:42 PM
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Did not want to hijack Matt's thread about his cracked wing problem.
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"I NEVER cut the fuselage to install the wing. My 1/32 ply nose doublers go to a little over an inch behind the hinge line. This doubler also does not have a straight cut at the aft end, but rather is elliptical at the aft end. I then slide the wing into place. Yes the flap horn in in the wing slot before installing the wing, and then permanently affixed to the wing. I have not had fuselage cracks since I started doing this many, many, moons ago."
So how do you handle the wing cutout if its for a tapered wing (swept back LE). The cutout on at least one side of the fuse will have to be oversized for the center of wing to pass thru. In what part of the airfoil do you oversize the cutout ? How much of a gap do you end up with and how do you fill that ? I agree with you, I hate to cut thru the fuse sides and doublers to take out the bottom saddle.
At one point I was thinking about how to build a tapered wing, but have just the center section (about the width of the fuse plus the fillets) constant chord just because of this issue. Never did follow thru with the idea, what do you think ?
:)
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Allan:
I'm not Tom, but I'll give you my approach: I slide the two sides of the fuselage onto the wing from their respective wing-tips. I will have my wing and motor crutch already jigged (with the nose formers already assembled into the crutch.) Depending on your preferences, you can have the doublers already glued to the crutch, or you can have the doublers already glued to the fuselage sides (just make sure you have a right side and a left side!)
Scott
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What Scott said.
I glue doublers to sides to make sure of good lamination and squeeze out the exta glue.
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Allan:
I'm not Tom, but I'll give you my approach: I slide the two sides of the fuselage onto the wing from their respective wing-tips. I will have my wing and motor crutch already jigged (with the nose formers already assembled into the crutch.) Depending on your preferences, you can have the doublers already glued to the crutch, or you can have the doublers already glued to the fuselage sides (just make sure you have a right side and a left side!)
Scott
Hey, I like this idea. Will give it a try on my next build. I will also use my fuse jig at the same time..
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When I built my 1978 Top Flight Nobler kit a couple of years ago, the die crunched fuselage sides were so bad the wing sheeting kinda shouted at the edges of the fuselage sides. I ended up putting in 1/8" square around the wing openings to shore up the gap, and put in wooden fillets just to make sure it was strong all around.
(aside: building a full-bodied stunter when you can't go three flights without crashing is dumb).
I, too, like the idea of sliding the fuse sides onto the plane. Or make it a take-apart...
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I would bet there are 10,000 or more stunters built by cutting away the lower half of the fuselage sides to hoist the wing in place. The same pieces are glued back with small ply doublers across the cut lines. This HAS to be stronger than and un-cut fuselage!
F.C.
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Allan,
With the exception of the new Hobo which has a straight wing, all of my airplanes have tapered wings. The fit at the fuselage is tight, but in most cases it is do able by just slightly blunting the leading edge at the center which is inside the fuselage. There is only a small difference in the airfoil size from the centerline to the wing cutout.
I build my fuselages separately so that I can get everything shaped and then remove any part that is in the way and then slide the fuselage onto the wing. It is much easier to the fuselage right without the wing in the way.
I know that many cut the fuselage, I just avoid doing if at all possible. I agree with Ted also. If you cut the fuselage you must use triplers in the area.
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I agree that fitting and shaping all the top and bottom blocks or moldings to the fuse is much easier if done before the wing is in the fuse.
So I will use your method on next build.
When you said "blunting the LE", do you actually remove material, or just kind of temporarily crush it flat and it returns to original shape after wing is in.
Another option would be to open up fuse cutout on the one side only. I would think that it would only have to be opened up from high points to the LE, and only about 1/32" max which would be easy fill with small ply shims.
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Watch Billy's video on building I-Beam wings. Builds the fuse first with top and bottom blocks. Then removes them to build the wing. Even tail surfaces go on while it is still nailed to he work bench. H^^