Dennis,

I think the water is entering from the horizontal stab while the plane is
sitting on the ground in the rain. I have had this problem for a while. I
finally solved it last year by drilling my drain hole bigger. The LNC2 plans
call for a drain hole in the fuselage under the horizontal stab. I made mine
too small. What I discovered was that the surface tension of the water was
preventing it from draining out the hole. When my plane sat out in the rain,
water would pool in the fuselage. I have bailed out about a gallon of water
in the worst case after heavy rain.

Mike Reinath
LNC2 N3602M at 815 Hrs TT
San Jose, CA (RHV)