>> Laminar flow depends on the accuracy of the airfoil and condition of the
surface. You just can't beat the precision
of a layup in a stiff mold.<<
The most important criterion is waviness of the surface in the chordwise
direction. .003" per 2" lenth was a figure mentioned. Don Dykins (he designed
the Europa airfoil) told me that actual overal dimensions were less critical.
Surprisingly he also said that contamination of the leading edge was less
critical too with modern NLF sections. Certainly the Europa doesn't react to
rain as much as the early glass gliders used to. But then the L/D is much lower
so perhaps one wouldn't notice it.
The sandwich on the XS wing has a 3mm pvc foam core, I believe. Roger?
Vibration caused by the engine can ruin the laminar flow if the skin is not
stiff enough, which is a function of the thickness and damping qualities of the
foam core. Also the number of ribs. MCR01 needs a rib every 6" or so to support
the thin metal skin.
Regards Graham
Graham
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