Changing XL dihedral angle?

[Arcane]

Has anyone had experience changing the dihedral angle on the XL? I was thinking of increasing the dihedral angle of the wings to 5 or 6 degrees. This might turn it into a two axis plane but also it would no longer have a stall and with increased flight time the wing struts could be shortened to return to normal flight control. Any thoughts on this would be appreciated.

Thanks,

Bill

[Bob S.]

... I was thinking of increasing the dihedral angle of the wings to 5 or 6 degrees. This might turn it into a two axis plane but also it would no longer have a stall and with increased flight time the wing struts could be shortened to return to normal flight control. Any thoughts on this would be appreciated. Thanks, Bill

Adding dihedral will definately add stability and make ailerons almost useless thus making it more like a 2-axis plane but as far as removing any stall tendancies, I doubt that... But I may be wrong..... I am not an Aeronautical Engineer and didn't even sleep in a Best Western or any other motel lately...

[Dan_]

Any thoughts on this would be appreciated.

I'm not an engineer either.  I do watch a lot of T.V.

It is a high wing already.  Therefore it benefits from the pendulum effect...  It has plenty of dihedral already.  Adding more is going to increase the likelihood of crosswinds raising the upwind wing, and lowering dutch roll damping.  

https://en.wikipedia.org/wiki/Dihedral_(aeronautics)

http://avstop.com/ac/flighttrainghandbook/freedirectionaloscillations.html

Take a look at the world's best trainer aircraft, a Cessna 150...  Hardly any geometric dihedral, but with the high-wing pendulum effect it has plenty of effective dihedral.

[Steve]

Chester Thomas built his LE with 6 degrees of dihedral... He flew it a lot and from a farm strip... He was a high time UL pilot and builder... Chester was light (around 150 lbs) and that makes a huge difference in how the UL performs and handles... He sold the project to a guy in the 225 lb range that wanted to fly out of a tight strip... The new owner put a Rotax 503 on it and flew but I have no further intel on the plane's performance characteristics or ownership track... Seen here: http://www.angoraaffaire.com/leu/id69.htm

[stevejahr]

...t also it would no longer have a stall...

Increasing dihedral will NOT eliminate stall.  The only thing which eliminates stall is either not flying or keeping the AOA below the stall threshold.

Ailerons will continue to work no matter the dihedral so not entirely accurate to call it a 2 axis airplane either.  Increased dihedral will increase the rolling affect with yaw.

[Arcane]

Thanks for the replies guys. I was thinking of making the LE fly more like the SkyPup but with strut changes be able to convert it back to original specs, however from what has been said, it seems like a bad idea...

Bill