Getting started on the wing fairing

The first thing to do before starting on the fairing is to turn the fuse upside down and tape down some wax paper across the entire wing saddle area. This will keep the fairing structure from accidentally getting glued to the wing. Once that is done, mount the wing and turn it upright again, then "rough in" the overall outline of the fairing with some low-tack masking tape.

Now we need to add the horizontal fairing web that goes from the trailing edge of the wing back to the rear fuselage. I cut this from some scrap lite ply stock and glued it in place with Alyphatic Resin. The edge that meets the TE of the wing should just be taped into position, be sure not to glue this area to the wing.

Next is the vertical web that joins the LE of the horizontal fin to the fuse sides. This is your main structural brace, and also acts as the key point determining the concave shape of the fairing. I cut this from 3/32" aircraft ply and glue it securely to the horizontal web and fuse sides.

Lastly, I add some thin formers and stringers that begin building up the "blend" that will take place between the fairing, fuselage and wing in this area. On the fullscale plane, the belly of the plane is nearly flat, so all I'm trying to do at this point is to begin transitioning the more cylindrical shape of the rear fuse into the flat belly that I will build under the wing.

Now we'll start sheeting and blending to get that nice "flat belly" that we all wish we had ourselves. I begin by sheeting the rear fairing underside with 1/16" balsa sheeting. Secure it and let it dry sufficiently.

Now I begin laying up a grid of balsa formers and stringers again, this time on the belly of the wing. This will begin blending the flat area from the fuse into the flat of the wing. On the fullscale plane, this area looks like a flat continuation of the lines from the rear fuse.

This presents panel lines that will line up as some natural seams for the balsa sheeting at this point. Therefore, the edges of this sheeted panel will not get blended into the fuse. The edges will align with what will be panel lines when the plane is finished. The leading edge of this panel will lie underneath yet another panel that will be added after glassing, so it won't need blended/feathered either.

There is a unique cutout shape at the leading edge of the wing where the fuse blends in, which just happens to fall about right where my front wing bolt is. I built up the blend and left the cutout area as per the scale lines of the fullscale FW190. After adding a little balsa putty and sanding, I've got a start on the feathering process well under way. That's pretty much it for the bottom side.

Finishing off the wing saddle

Now we can finish off the wing saddle area. I cut out surface sheeting for the wing saddle from two pieces of 1/32" aircraft ply, seamed in the middle and extending an extra 1/8" past the saddle edges. This provides a very hard and durable surface for the saddle, but adds very little weight and more importantly, almost no thickness. Anything over 1/32" thick would have changed the fit of the wing and made the fairing not line up properly. I glued the sheeting down with epoxy, taped and clamped it securely and let it set overnight.

The next day, I mounted the wing and set it upright to double-check the wing incidence and fit of the fairing now that the saddle is finished off. Once that checked out, I took the wing off and sanded away the 1/8" excess aircraft ply from the saddle edges.

Now I only have two more surfaces yet to be finished off. The front and rear lips of the saddle depression in the fuse were also covered up with the same 1/32" aircraft ply. But, before doing this you need to make sure you sand away enough to allow some slop in the wing fit. You'll need about 1/16" of clearance at the LE and TE of the wing to allow for the front and rear aircraft ply and the eventual glassing and painting. Without these gaps, you'll find that you can't fit the wing back in the saddle when the plane is done!

With the saddle pretty much done, all that is left now is to go over everything with balsa putty again and sand it to a relatively smooth and feathered blend everywhere. This usually takes several passes to get it to satisfaction.

Realize that this step doesn't really have to be perfect, as you will be doing a good bit of puttying later after glassing, and, you will be adding panel lines back in where many of these seams were anyway.

But, you still want the overall surface to follow a natural blended contour with shallow panel lines, not abruptly changing angles or crooked seams. This work now will give you more flexibility and less puttying later when you do your final finish work.