Modeling Tubular Frame

[cwilliamrose]

Jeffery,

No need to worry about making the bends perfect, once you weld the tube clusters it will all change anyway. The Bellanca used curved longerons to give the fuselage smoother contours and the tube size most likely had to be larger to provide enough strength and stiffness to make a valid structure. It's a trade-off the designer was willing to make. Most airplanes have straight tubes that approximate a curve and that method will yield a lighter structure.

Rob,

Splines aren't supported in the weldments tools. You can get close to the spline's shape using a series of tangent arcs. A bit of a PITA but you only have to do two of them (then mirror for the other two). If the spline is in 3D space instead of being on a plane it will be more work but still doable. My engine mount's curved tubes are just single arcs on planes. The curved tubes are thicker wall than the straight tubes;