Jonathan St. Cloud wrote on 10/24/2016 11:49 AM:
One would think if the blow holes did not add much a pencil pusher at
the factory would realize they could have lots of man hours ($) by
just using dimple tape.

Schleicher has used blow holes from at least 1984 on the ASW20C and B.
The holes were thin metal tubes on the wing bottom, and looked like they
might be costly. My ASH 26 E does not use the tubes on the wings;
instead, the blow holes are drilled into the the bottom of the flaps and
ailerons. That's not on the wing, but on the control surface!

My guess is the boundary layer is too thick on the control surfaces for
zig zag tape to work, unless it was stacked two or three high.

Drilled holes are probably cheap enough, and installing the tiny NACA
scoops is easy, too.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"

https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf