Op maandag 8 april 2019 13:30:06 UTC+2 schreef Dave Walsh:
At 10:58 08 April 2019, Senna Van den Bosch wrote:
I'm seeing this more and more but have no idea what they're
called. Refer
to this pictu
https://cdn.jetphotos.com/full/6/53013_1459261993.jpg
This was Stefan Langer's Libelle, it's got those black plastic(?)
thing at
the aileron and wing. So does this Cirrus:
https://cdn.airplane-pictures.net/images/uploaded-
images/2017/10/14/975766.jpg

What are they called and do they help in performance? Would it
be worth
installing?

They are aerodynamic "fences". Standard on inboard end of
flaps/faperons on many gliders, DG800, Antares and others.
All mods make you go faster, no?

I've googled a bit and found this document testing the effect of those fences: https://tu-dresden.de/ing/maschinenw...TS.pdf?lang=en

Fairly neglectable, even 5 pairs of fences were teste: "...the loss in overall performance by applying for
example four additional pairs of fences on the
wings of an ASW-28 (Fig. 1). The result was a
decrease in maximum L/D of about 0.25 points
for a singe pair of fences..."

Worth the read