tegirinenashi wrote: ↑
Wed Sep 05, 2018 5:00 am
DAnderson wrote: ↑
Tue Sep 04, 2018 8:14 pm
I've seen alloy fuselage bent as well fyi
I doubt it. First of all, it is all about the leverage: it is easy to bend a bar when you have 95 cm of leverage -- the full sized mast. It is harder to bend 65 cm one, but as Gunnar demonstrated, still quite possible. Compare it to fuselage, you have perhaps 20 cm to the front wing, and perhaps 50 cm to the stabilizer. At first sight, bending the tail section of the fuse looks probable. I'd suggest, however, that if you hit the reef with the stab but not the front wing, then you are so unlucky that you'd better quit foiling to avoid future serious accident.
goto the ocean someday and lose your board in a wave, or heaven forbid drop your foil board
Also, what is the mast thickness, 14-15 mm? Compare it to fuselage, which is at least twice as thick. Keep in mind, that competent designer would shape the tail section of fuselage tapered, so that the bend force momentum would be kept approximately constant along the fuselage length. Speaking of tapered fuselage tail section, it is good for hydrodynamics as well.
if bending moment was the only design criteria, that might make sense
but you also have to make sure you have enough material for screws to go through and still have strength around the holes
and since you bolt through the fuselage, making it solid makes it impossible to crush from the bolts or an impact
also you have torsional loading on the fuselage so if you were to taper it, it would not be as stiff in torsion
you could make it hollow and increase the size of the fuselage and make it lighter, like oversized tubing on bikes
now it is larger and probably has more drag as a result, hollow means it could leak, and you have that whole crushing problem again
you also have to manufacture the thing and make it somewhat reasonable to purchase
you also have to compete with carbon