Hansen Aerosports wrote:
My conclusion is that
a center strut stabilizes the canopy (and profile)
... the canopy is 'jammed' forward in the center of the kite and the profile in this critical area becomes distorted.
The distortion is a function of load and creates a less stable and predictable flight response as the load and distortion changes. A center strut provides a compressive-resistant member
My conclusion is
a center strut and the wingtip struts are the most important struts in any kite.
While a 4 strut may be lighter (and cheaper to build) than a 5 strut, I have not found them to be superior to a 3 strut kite and the popularity of...
Thanks for your response ,I learned a bunch ; & making correlation(s)-- between a HG & a kite-board Kite
i see what your talking about when the airfoil gets jammed forward.
I've had battens Fall Out while flying because the device holding them in
was broken. When this happens there is a distinct deformation from the
high-point of the air-foil and it travels forward.
I "Think" this contributes more --parasitic drag--,(drag caused from distortions), than anything, causing a mild Yawing turn if the batten that's missing is towards the tip.
I "Think" what causes the main problem is now that the air-foil is shifted forward,
it also distorts the Trailing edge. This will add --induced drag--,(a change in
the way the air flows causing Lift).
If Ya place a Flap on an airfoil then put it down a bit, it will make Lots of
Lift "AND" Drag . A distorted Trailing Edge on a kite,will cause the air that flows off
the airfoil to do much the same.Only it's Random lift & drag because the distortion
never stays the same for more than a moment or two.
Replay the first 0:08 seconds, 3 or 4 times
On This one, go to 1:08 and watch how the turbulence comes off the
back of the airfoil as the Angle of Attack is increased.
Nearly the same things happen when Ya change the Trailing Edge,(TE)
of an airfoil ; Only the change is WAY more drastic because the actual
Lift of the foil is changed.
And Last, this as a visualization for what the air flowing Off the Trailing Edge
of a kite that has flutter, ((not supported well or flapping like a Flag)).
http://www.youtube.com/watch?v=woLm7dWs ... re=related