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LAdamson

Cardinal dihedral? hmmmm sure looks like it to me!

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:-lolGeez, Hornit.. you done stole that idea from me. I was just perusing those sites and you beat me to it. Dang!!!But, before everyone jumps on this.. keep in mind that these are illusions generated by the photography. Yeah, right.. parallax and all that stuff. No wait!!!! They are under lift and that is "bendage", certainly not dihedral. That's the correct answer! :)Can you tell I am really really tired of this subject???

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Goes to prove it's tough making a firm decision from a photo, doesn't it? L.Adamson

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Let's remove all the extranious stuff, draw some parallel lines and expand the picture somewhat. Geez, that be dihedral. :)Now, can we put this subject to rest? The airplane has dihedral. There is no such thing as an aircraft that has zero dihedral (in the modern era that is). Now, can we move on?

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>Now, can we put this subject to rest? The airplane has >dihedral. There is no such thing as an aircraft that has >zero dihedral (in the modern era that is). Now, can we move >on? Yes there is.....I'd have to check to make sure, but check aircraft such as the aerobatic Extra300, Sukhoi, etc. The idea is to prevent rudder from causing the aircraft to bank due to dihedral of the wings.An simple R/C plane with only rudder control and no ailerons will have an extreme amount of dihedral to begin the turn. We don't want these newer aerobatic aircraft to start rolling when using high amounts of rudder for knife edges, etc.L.Adamson

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Okay, okay, mea culpa.. I should have said "except for aerobatic aircraft where roll stabilization/stability is critical". Which, OBTW, does not describe a Cardinal. :)

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>There is no such thing as an aircraft that has >zero dihedral (in the modern era that is). Tom,There may be aircraft however that has "negative" dihedral. Take for example C-5A Galaxy military transport. It is my understanding the dihedral is to add lateral stability but with a heavy fuselage suspended underneath the wings there may already be "too much" of this stability therefore wings are bent downwards in effect creating negative dihedral.Michael J.

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Yes, BUT, THERE IS dihedral - negative or otherwise. And that's my point (with the exception of my caveat above). Heck, even a helicopter has dihedral. Now, you figure that one out. :-lol

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We can continue this converstaion over the Saturday banquet .. :-lolMichael J.

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>Heck, even a helicopter has dihedral. Now, you figure that >one out. I'd say that has to do with flexing of the individual blades in lift. For instance, each blade may constantly change angle as it travels around the "swash plate". To move the helicopter forward, the trailing blades will have more pitch than the forward ones. This will look like a "dinner" plate tipped slightly forward, and now what looked like dihedral on the front blades will be level or even negative. Any other questions, and arn't you glad I won't be at Tahoe? ......... I'll just be a bit jealous! :)L.Adamson

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Please, no one jump on me...I don;t mean to help beat a dead horse, but negative dihedral is (correct me if I'm worng, please) called 'anhedral,' which CAN be referred to as negative dihedral, however it is not completely correct to do so. I just had to throw this up...

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No no no.. You got it all wrong. Of course. :-lol Otherwise I wouldn't be responding to this techno-weenie-geek-a-zoid stuff. A rotor in stasis does have dihedral. Put it in motion and all bets are off - but it does provide a starting point from which to gauge the physics. Pitch has nothing to do with it. If you have or could view a rotor blade in slow motion, photographed from the center of the rotor head, you would crap yourself. Never the less, forward or aft travel has everything to do with it. Its related to blade stall and is called articulation; but that has nothing to do with dihedral.

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