' Bend like a willow , my son ' ? With spruce cap strips ,
you can put the fuselage over your knee , covered with
silk, you can maybe get two in deflection at the tips ,
(rather carefully) if youve used good hard wood for the spar.
More than ' good hard ' timbers , its timber selected for Good Grain,
no knots , whorls etc. SO , you dont need all this fancy 4 - 6 Lb
unobtainium. The ribs being only about 1/4 in deep (7mm is good)
to build a strong plane at a sane weight .
The Folkerts I built used all 7 to 11 Lb wood , softest for fuse sides
though its an oval Fuse. tissued and doped . about 57 Oz. for 700
Sq. In.Handles rough air / wind really well.
Has had 4 hits from brain fade, two cuts at top of wing over, run like stink
and get lines tight to turn as ' contact' is made.though the shock from the
'grab' on the lines I believe removes much inertia. A wing over take off from
a stooge up hill into wind in a farm paddock, soft ground.pulled it out , hosed
the intake out and tried again.
A torque induced ' come in ' inverted on a rich run , clowning.When shed come
over the top lines loose swinging upright and I hit full down as they tightened,
and a inverted hit in bunts in wind pulling down over five of em when I wasnt
paying attention ( to the plane ! )
And , the worst damadge , hurrying out of the shed and getting the tailplane
caught between the knees , spliting one side of the fuse under it .
was glued together with Great planes Aliphatic and ' a few ' ply doublers with aryldite .
Hence " you dont need 4 - 6 Lb wood "