PRANDTL lift distribution as it relates to flying wings.

[Doc J]

Hi,

A complementary question on the one from Thursday about how Prandtl-D and M fly,

BSLD is a way to optimize drag for structure weight. I'm looking for a plot or equation for the bending moment along the span in the BSLD, to try to understand how the spar should evolve.

Mark Drela analyze spar "tapering" for Elliptical lift distribution as reported in https://www.rcgroups.com/forums/showpost.php?p=5151778&postcount=3

I wonder what should be considered for BSLD.

Seems that XFLR5 can calculate that, but the a XFLR5 model is needed ;-)

For Doc J: A thesis on the application of BSLD to gider's straight wings : Project Monarch: The application of Ludwig Prandtl's bell-curve span loading to a straight, high performance sailplane wing

Many thanks. I had not seen this.

Doc.

 

[jmf11]

Hello Red,

I'm not used to duplicate questions that way, but I'm really interested about how the Prandtl-D and -M "feel" under pilot sticks, especially on the yaw axis. I asked here Prandtl-lift-distribution-as-it-relates-to-flying-wings #58 , but the thread went through a bit fast at that point. I just wanted to confirm if you had no answer on that point, if I could look for already given answers somewhere else, or if you had not seen the question.

And if files /drawings of the 35" Prandtl-M were shared by the NASA. This size would be possible to use for hobbyists, without scaling artifacts. I dare ask, but would fully understand if kept proprietary for the moment.

And by the way, I really like the simplicity of your mini wanderer

Jean-Marc