I understand the tube is far better from a strength compression standpoint than a flat surfaced beam, but at the amount of forces we're talking about, is that really significant?
Another advantage. It is a pain in the butt to mount hardware on a round tube as opposed to the flat style beams.
All very true, although the magnitude of the difference may proof to be very little. Having said this; high quality ROUND tubes are fair easier to source than special extruded rectangular sections of the right strength/stiffness/weight. That is why the Blade homebuilding plans use the round beams.
But still I wish to underline that a homebuild Timber Blade with normal quality round beams (plain T5 alu instead of high strengh T7 or special allow) resulted in a stiffness that was a factor 2.7 stiffer than a young Tiger F18 that used oversized square beam sections. Something large opposite of what a quick look and gutt feelings may suggest.
So while in theory you say truthful things we must take care to not let such a single difference in potential colour our perception of the whole situation.
Wouter
