I'd think a mast section would have a lot more flex to it than a beam section should have. Masts are designed to take more compression loads and to flex within the limits of the diamonds etc. You basically don't want any flex in a beam.
Perhaps you could use a mast section as a starting point and reinforce it with more layers of carbon to get it stiff.
Mike.
Fred,
As I recall, the P-19 crossbars are mast sections and not round tubes.
You could save yourself a ton of work if you used a section of carbon mast.
Maybe you could find a broken I-20 mast or an A Class mast and build it up as needed.
