ORIGINAL: MinnFlyer
ORIGINAL: darock
First flight, flutter. What caused it? Sealing the gaps obviously. The theory? Who knows. It happened.
Case closed
Not obvious and not closed.
This is anecdotal evidence at best, not an explanation of how sealing a gap can induce flutter. There could have been other things done, even unintentionally, when the plane was worked on that caused the flutter. And even if sealing the hinge lines in this case did contribute to the flutter, that doesn't mean that leaving gaps open is the best practice.
You still have not answered how a gap can "CAUSE flutter". So I have forwarded the question to a friend who has a masters in aerospace engineering and 35 years experience designing aircraft, flight simulators and missiles for NASA and the military. He is out for a few days but when I hear back from him next week I will post his reply.
Dave