Hi, Chuck --
I've almost completed all my flying surfaces, and 2mm of bowing over 44 inches
isn't much. Checked the flaps yet?
I don't think this will be noticeable unless one were to sight along it to
specifically look for it, as the surface is curved chordwise distorting light
reflection. Anyway, I'm using Poly-Fiber's SuperFill, and the directions say
that 1/4" of filler is the maximum depth you can get away with. You have the
option also of perfecting only the top surface. As to flying qualities, I
doubt span-wise bowing does anything (think of how much a glass glider wing
flexes in flight). However, in adding filler, the airfoil shape is altered,
which is important in the first 35-40% of chord. So, I've been trying to keep
the filler thin there. Also, the length of the sanding spline determines how
much bowing you remove, and splines shorter than 36" (I'm using 18" and 22"
inch) are easier to work with and still produce the desired results.
I doubt heating the thing and trying to reshape it would either work or be
wise. These things are structural and tend to ensure one landing for every
takeoff!
Hope this helps...
Regards,
Fred FIllinger, A063
> Hi guys-
>
> I have finally gotten around to filling the flying surfaces after having
put
> it off about as long as I could. I have filled and finished the rudder and
> vertical fin and control surfaces with no problem. However, it became
> obvious
> while sanding with my 36" long spline that one of my tailplanes has a bow,
> that is, it is concave on one side and convex on the other! How this
> occurred
> is a mystery. It must have happened when bonding the two sections
together.
> Laying a straightedge to conform to the outboard section, the root is some
2
> mm out of line. Disaster!
>
> I am quite sure that the flying qualities of the craft will not be affected
> by
> this slight bow, but it bothers my aesthetic and craftsman side! What to
do
> about this? As I see it there are three avenues available-- forget it and
> hope that noone notices; fill the low areas with filler to make a straight
> surface both sides; or perhaps heat it to a point where the epoxy softens a
> bit and clamp it so that when it cools it will be straight. Has this
> happened
> to anyone else, and can you experienced builders suggest a reasonable
course
> of action?
>
> Regards,
>
> Pops
> A036
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