kenafp wrote:I would assume that shimmying and swaying would be a potential problem that would show itself in an early run on the road. Once I get it registered, it will go on a test drive to look for any early problems that can get fixed before the build gets any further along.
Ken,
Either I wasn't clear or you are misunderstanding. Shimmying & swaying is not the issue. As you tow down the road, the vertical load at the three points where the tongue meets the front cross member is constantly changing causing flex that will eventually crack & break if not done correctly. Your center piece on it's own adds very little vertical strength because it will simply twist the front cross member. Therefore, the vertical load is all on the two outer pieces. By cutting the top & bottom flanges of the channels, bending them & welding at those two joints reduces their vertical strength at the point where you need it the most.
Airstream, BTW, runs the tongue back under the cabin so that the cabin is part of the structural strength.
Andrew's 'Tongue Strength' page is based on the Australian laws for building trailers. True expert advise, I'd say. Run it by the professor.
Fred