I was just wonder, what would a negative dihedral do to a planes stabilty or flight??? For instants if you were to place a trainers wings upside down? Are there planes out there like this???


Just a stupid question I just thought of! Anyways, thanks for the replies!

It is called "anhedral".

It would decrease the planes lateral stability.

Which is another way of saying that the plane will be more eager to roll when commanded to do so.

Search and you'll find info around here.

This is interesting: http://142.26.194.131/aerodynamics1/...ity/Page5.html

...scroll down to the bottom and read the section titled "Reducing Lateral Stability".

Hey Jim, thanks for that! Thats helps out a lot!

My guess would be it would fly like a trainer flies upside down. That is, it would be possible to fly but it would always try to turn over. I cant imagine a logical use for it (or someone would have an airplane with it). I think realflight lets you change dihedral, maybe you could change it to negative and see how it flies.

It would be more like a low wing airplane flying upside down than a trainer flying upside down.

A trainer flying upside is completely unstable in that position. It "wants" to flip over... that's the whole point, actually.

The fuselange of a low wing plane is like an inverted pendulum - it wants to fall over. The wing has dihedral to counter the effect of the inverted pendulum so that the net stability is neutral, or slightly positive. Flip it over (fly it inverted), and you get the trainer with anhedral. Taking the dihedral out of a low wing plan can move it from being nuetrally stable to negatively. Dihedral has to be balanced against other effects.

Here some interesting info on the subject presented by Ed Moorman, who posts here on RCU:
http://members.cox.net/moorman1/ProjectJoss.htm