What does it?
A wing with a properly designed winggrid shows the following
properties:
1. Very low induced
drag (Compared to conventional wings induced drag is up to 60%
smaller). This effect can also be described with the span
efficiency e . With
winggrid e can be up to over 3.0 compared to e's of 0.7 to 0.9
with conventional wingtips (see also the classification of
the winggrid among other
wingtips.).
This main effect was already demonstrated with an asymmetric test
configuration at model scale, cf. pictures of a modified UHU
below.
If such an asymmetric model with no vertical stabilizer flies straight, then obviously both wings
have identical drag moment relative to center along z-axis (and identical lift
moment for no roll along x-axis). We used this contraption to screen about 40
different wingtip configurations, old and new; some relevant results were:
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The following schematics of wings
with identical glide number and specific load show the magnitude
of the effect:
a) conventional wing with half span aspect ratio of 7.
b) wing with winggrid, same area but 64% span.
c) wing with 100% span and 245% lift
2. Increased resistance to tip stall. The test plane showed very high resistance to tip stall even in wet conditions (rain). This feature increases flight safety.
3. The winggrid generates a rectangular lift distribution that leads to an increased overall lift of 127% for rectangular planform wings and a slope of the lift curve of nearly 2*p. It reduces the ground effect during take off and landing. The tip vortex compared to an elliptic wing is reduced due to the fluid flow through the winggrid.
4. The winggrid leads to an increased efficiency of the flaps due to the rectangular lift distribution and resistance to tip stall.
See FAQ's to the manned experimental proof of
concept, which clarifies a lot.
However, a wingrid improves well designed aircrafts only.
See "Design Rules for the Winggrid".
