REFLECTOR:Lower Winglets

[Pat Shea]

 Thanks for the aerodynamic theory and the pressure
pics Al.
 I should have been more clear - removing the lower
winglets effectively reduces the total wing area which
I wanted to replace (that whole canard-to-main wing
balancing act). I also wanted to replace the lost
"tail-feathers" for yaw stability. As you pointed out,
there certainly are other aerodynamic effects. 
 Do you suspect the wing without the lower winglets
will be less efficient at cruise (slower) or just less
stable at the low end?  Duane didn't indicate N97XL
exhibited any nasty behavior at low speeds - then
again, he flies these things for a living...

Thanks, Pat
   
--- Al Gietzen <ALVentures@cox.net> wrote:
> About 7-8" was added to the top of N97XL's winglets
> to compensate for the lost lower winglet area.
> 
>  
> 
> I guess I may as well add my 2-bits worth of theory
> on this issue as
> well.  
 
> From an aerodynamics standpoint, I don't think
> adding height to the
> tipsail bears much relation to removing the bottom
> extension (lower
> winglet).  It may add a bit to the yaw stability
> because of the
> additional inward force, and can add to rudder
> effectiveness if you also
> lengthen the rudder.





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