<<I'm putting the flaps on my 360 and have a couple questions to the
experts.>>

I did something stupid.  I built my right flap two summers ago and forgot all
of these important details.  Now I have to build the left flap.  I guess the
important thing is to make sure they match.

<<The spar on the bottom flap skin is shown to be in front of the foam insert
on the blueprints (J). But that's not possible on my bottom skin.  Is it
alright to put that spar on top of the foam insert?>>

I don't see any problem with placing the flap spar on top of a lower flap
skin which is glass-foam-glass rather than glass-to-glass.  The primary load
carrying element here is the multi-ply BID tape that forms the corner.  If
you're nervous, you can make sure that BID tape extends all the way onto the
glass-to-glass portion.  On the back (internal) side, why can't you just lay
the BID tape onto the glass-covered-foam?  There are many areas where we bond
to covered core.  Baggage bulkheads get bonded to fuselage shells containing
core, every wing rib is this way, the cockpit closeout ribs are this way --
what is the problem?

<<This will shorten the phenolic insert (bellhorn) some.>>

No, you can carve out the foam core here locally.  And if you don't want to,
just make sure that the bolt holes and nutplate rivets go thru the phenolic
insert.

Oh, don't forget vent holes!

I made a mistake the first time around and made the flap spar the height
recommended in the manual.  I found that to be about 1/4 inch too short --
the flap would have been way too thin.  So I added a tapered foam/micro shim
to the top skin and covered that with BID before closing the flap.  I intend
to weigh both flaps and see how much weight this mistake cost me....

<<If the promximal end of the flap meets the fillet of the fuselage (top to
top), does the distal top skin of the flap tie with the top of the aileron
skin in this condition?>>

My wife is in the medical field and talks this way.  I can't understand her,
either.  (although perhaps this is more fundamental than a terminology thing
-- you married guys will understand, I'm sure...)

So the question is ... if the inboard flap matches up with the fuselage
fillet, where does the outboard end match up with -- the top or the bottom of
the aileron?

I ran a metal angle from the flap fillet inboard to the wingtip rib.  I'm
sure I clamped the angle to the bottom of the flap fillet with one of those
cleco side grip clamps.  I think I put the outer end on a small stepladder at
the right height.  Or maybe I had the aileron attached and clamped into an
in-trail position and placed the angle up against the end of the aileron --
in this respect I think Scott Krueger and I agree.  Where we disagree is that
I used the top surface of the wing with the top surface of the aileron as "in
trail".  It was very easy to determine with a 12-inch metal ruler.

The most important thing here is that the flaps are free to twist a lot, at
least until the top skin goes on.  You definitely need a metal angle to hold
the flap unwarped -- or warped the way you want it -- when you close it out.  
Don't close it out on a workbench -- do it in place on the plane with the
ailerons attached or it won't be right.

And you wonder why all those other guys display their Lancairs with the flaps
down, eh?

<<Does in-trail for the aileron mean you place a straight edge tangent to the
top skin TE of the wing and the top skin of the aileron is tangent to the
straight edge too?>>

Yup.  That's how I did it.

Good luck!  It was a bunch of work but nothing difficult.  And quite
satisfying to see the flap retract and extend with a nice even gap to the top
skin -- even if it is just by raising and lowering it with my hand....

- Rob Wolf
LNC2 51%, maybe more....