On Aug 17, 2:03*pm, wrote:

I doubt you have found the real problem yet...

I agree with Hank: The fore-aft play of the stabilizer may be a
contributory factor in the lower hinge disengagement, but I bet you'll
find that the primary cause is a misalignment elsewhere in the rudder
pivot system.

That said, I have always been some combination of amazed and unsettled
by the relative casualness of the drag/thrust attachment of the L13
(not L23) vertical stabilizer.

The stabilizer is basically attached to the dorsal "chine" along the
top of the fuselage where the right and left skins join. If you look
closely at the forward end of the vertical stabilizer root rib, you
see three or four 3/8" or so holes for the screws that attach the
stabilizer to the chine. Near as I can tell (and feel free to
demonstrate otherwise), there are no special considerations to
reinforce the chine in that area or to reinforce its connection to the
nearby bulkheads.

As a result, even on a healthy Blanik there is a somewhat generous
amount of fore-aft play to the stabilizer. Pressing the stabilizer tip
forward and aft just affects the ellipticality of the fuselage cross-
section in the area of the stabilizer forward attach.

Don't get me wrong, I think the stabilizer attachment is perfectly
airworthy as-designed and as-built. The longitudinal flight loadings
on the vertical fin are relatively modest under normal circumstances,
and the attach is demonstrably adequate for those loads. But I do
somewhat question the long-term serviceability of the assembly,
especially when the aircraft is moved and handled by untrained hands.

Thanks, Bob K.