Looking at the drawings, the dimensions were plotted on the jig table. The top longerons are basically straight, but the last 32 inches gently curves down 2 inches.
The lower longerons curve a whole lot more.
Here is how we did it. First, a length of tubing was clamped in a vice.
Heat was applied on the top and the bottom while pulling a steady pressure on the end of the tube.
If you keep working this slowly, heating six or seven inches at a time, the tube takes a nice gradual bend. I pushed the tube with my left hand while heating with my right one.
After a few heat / check. heat/ check cycles, the top longeron was done.
The lower longeron has a lot more curve.
Tube in the vice, the process was repeated.
Getting close. More heat.More pulling.
This is as far as we got today - the kids were on their way home from school and I had to stop. The top two longerons are bent and one lower longeron is half way there.
More soon. Enjoy