But the 26 is the only one with blow turbulators and it goes no better
than the two gliders without. I think you just made my point.

Mike
In the case of the 26 and 27 one must not narrow it down to just the
blow holes. Aside from the structural features, the gliders have
incorporated truly aerodynamic advances. For the gliders to
perform as they do everything had to work just right. Consider the
fact it has the smallest wing area of the " three" the Diana is even
smaller. It has the highest dry wing loading of any 15meter class glider.
Still it is able to soar with the lightest in its class, with only the
slightest
disadvantage. As soon as the wingloading goes up, when conditions
allow, this glider is in a class by it self.
At the time I thought Waible should have gone about it incrementally,
rather then design a radical new glider for production.
Look at the fuselage shape only, it required a new wing/fuselage juncture.
The others still use the wing straight into the fuselage.
The airfoil had to generate more lift due to smaller wing area as well make
it thinner to reduce drag. A small gain could be realized with the higher
aspect ratio that came with this wing lay out. Waibel was the man that
knew/felt
laminar flow could be obtained past 90% of chord across a hinge line. He
pursued that goal with the help from Loek Boermans.
Also the wing fuselage intersection was L. Boermans doing.
The blow holes are not an insignificant part in making the glider what it
is.
If it could just shed 75lb of its empty weight and we would not have this
discussion about blow holes.
Regards
Udo