5.5 hours in an SGS 1-26; barely long enough for Silver C duration, but it was the best that I could manage.
I believe the unofficial duration record was established by a Hungarian fellow in Hawaii, also in a 1-26. As I recall, it was approximately 36 hours. The FAI stopped recording official duration records many decades ago, because of safety concerns.
Then there was that crazy record (100 days(!) or something like that) established in a Cessna in Las Vegas back in the 1950s or 60''s. Of course, that kind of stunt doesn''t require much real skill, just a lot of gas and oil, and some tricky arrangements for food, water and sanitation.
