lml@lancaironline.net Mailing List Archive

In a message dated 12/12/2006 1:45:22 P.M. Central Standard Time, marv@lancaironline.net writes:

Does the belly pan get bonded flat against the main spar
. It has a bit of an arc in it but could easily be clamped flat to the spar,

Sean,

Do you have a construction manual? It must not be clamped flat. You should have some high density Clark foam that would be shaped for a spacer and floxed between the main spar and the belly pan. It is about 1.5 or 1.75 inches at the center of the main spar and will have passages thru it along each side of the nose gear tunnel for electrical and hydraulic lines. The same idea is true for the rear spar area where the passage area is provided at the center in thru the area between the console sides and elevator tunnel sides - again, for hydraulic and electrical lines.

also does the pan run parallel to the main spar ? meaning at the ends of
the main spar your lap over the spar with the pan is about half the width of
the spar.

Yes, as you can see from temporarily fitting a stub wing top skin, they must both be firmly attached to the spar, flox filled and 2-BID (about 2.5" wide) in the joggle to secure the seam.

Mine if i make the pan parallel to the spar my rear fillets don't
match real well 1/4 gap on one side.see fig 5. Does the aft spar rest on the
foam core in the belly pan and does it run parallel to the aft spar exterior
of the fuselage area .?

See above, although the foam spacer would provide for a 1" to 1.25" or so distance between the spar and the inner skin of the belly pan at the center.

Is there any foam rib on the spar where the pan meets the main spar at bl 50
,or is that to be removed prior to bonding on the pan. The instructions are
very vague about the whole pan process but do say that the pan and main spar
are not for alignment purposes.

No. In fact, you may have to remove inner skin and nomex (for about 8" towards the CL) from the belly pan to fit the wing spar to the main spar.

I guess what I'm asking is, is my main spar to far fwd, is it angled to
far
in one direction, my measurements confirm that it is perpendicular to the fuse
IE tip measure to outboard spar ends.

There are dimensions in the manual, check them. You should have laid down and mark a center line (CL) on the fuselage. Each tip of the wing spar should measure the same distance from the CL. Select a CL point at the tail and measure the distance from each wing spar tip to the tail CL point - they should be equal for the spar to be square.

Is it better to have the pan run more parallel to the spar for good bonding
and just fill in at the gaps between fuse and belly pan? at the rear end see
fig 6 this gap is present when the pan is more parallel to the main spar.
Or is it better to have the rear joggle be perfect and the joints out board
of the joggle be perfect and not worry about the alignment of the pan to main
spar knowing that the top skin will bond to the main spar and the belly pan
making a good connection to the spar?

Make the best fit that you can so that the belly pan is structurally bonded to the spars with the ability of the 2-BID tapes in the joglles to properly finish th eseams.

I am not opposed to cutting out the main and aft spar to achieve a better
fit
but my measurements imply that its where it belongs. I feel like after the
pan is installed the spar is where its going to stay.

Check that the rear spar is square also. Cut the belly pan and cleco it while you figure out the foam pads.

Sooo No further
progress is being made cause I'm not going to screw up this part without
someone elses input.
Thanks for all responses I feel like I'm at a point of no return if i bond
in
the pan and its wrong.

If you want to talk, call me at my cell 630-561-0400.

Scott Krueger AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

A man has got to know his limitations.