Can Dihedral wing Angle negate the need for Ailerons

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Dav-h12

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Seen a number of opinions, all pilots, on this subject: If a wing has sufficient dihedral angle, ailerons are not needed. There have been more than a couple pilots in aviation history that have died from their designs modeled after birds(biomimetics). Speculative opinion: birds have exceptional “tactile” feedback as air flows over their wings which gives them exceptional control for ever slight adjustments. Something difficult to replicate in mechanical control/linear motion. Stick/pedal feedback sure. But not the same.
So can it be done? Additionally, could in flight dihedral adjustments be an option or would there be too much time lapse between pilot inputs to achieve the desired airframe attitude?
 

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TFF

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Negate is too strong. You can have enough dihedral to turn ok. What you loose is crosswind control. Flying RC with no ailerons is fun, but it is sloppy fun. Challenge to do it well. The plane will like the dihedral until you want to turn, then it will try and straighten out when you do. Good for learning, not as good once you know how.
 

bmcj

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IIRC, there were more Quicksilvers produced in the 80’s than there were Cessnas. The Quicksilver was two-axis with high dihedral and rudder, but no ailerons. The rudder provided an immediate and strong roll response, though you would notice a little yaw at the start of the roll (the “sloppy” part TFF referred to). The Quicksilver did have spoilerons too, but the spoilerons weren’t very effective; that’s why the stick controlled the rudder and the pedals deployed the spoilerons.
 
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Vigilant1

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I don't think the bird example is directly relevant to an airplane without ailerons. Birds warp their wings differentially to produce roll. One wing then has higher camber and lift, so the bird rolls. Some airplanes (including early ones built by the Wright brothers) also used this wing warping to produce roll. Now, most planes use ailerons instead to produce different camber and lift, because it is simpler, but it achieves the same thing as avian wing warping.
 

jedi

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I don't think the bird example is directly relevant to an airplane without ailerons. Birds warp their wings differentially to produce roll. One wing then has higher camber and lift, so the bird rolls. Some airplanes (including early ones built by the Wright brothers) also used this wing warping to produce roll. Now, most planes use ailerons instead to produce different camber and lift, because it is simpler, but it achieves the same thing as avian wing warping.
I don't think it is not quite that simple. but the answer to your question is contained in the posts above. The talks given by Al Bowers give a much more complete answer but the take away here is that the Wright brothers wing warping put the maximum angle of attack change at the wing tip and caused excessive adverse yaw. Birds are much better at controlling the span wise lift distribution to minimize or eliminate adverse yaw. Ducks do quite well with anhedral (same as the Wright brothers) and have no vertical tail.

 
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flywheel1935

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My original; Hummer Ultralight had no ailerons, only the butterfly tail for 'control',
its the scariest thing I've flown, in discussion with Francis Rogallo ( of hang glider fame/NASA etc )
we fitted spoilers ' really fantastic roll rate and roll control.
 

Gregory Perkins

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On the theory that no one should be flying ultralights if there is any significant wind, there was a large army
of two axis Weedhopper pilots including me that would swear their planes were the best handling and easiest to fly ever. ( on calm days ) For several months (in around 1981) the weedhopper was the most mass produced brand of any ultralight. The stick was connected to the rudder/elevator and the foot pedals were for brakes only. Crosswind landings when necessary generally were not too much of a problem with only a 40 or 50 foot rollout and you could land diagonally on the runway.
 

dkwflight

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Hi
While I have no experience sitting in a dihedral wing air plane, I have flown RC models built that way.
What rolls a plane like that is rudder. A turn is started by rudder. the plane rolls into a turn easily with rudder only input.
Dennis
 

Highplains

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Back in the mid-60’s radio control had what they called Class II models for competition with rudder/elevator/motor for a control system. Marvelous flying models, about the only thing they couldn’t do was knife edge flight. They rolled quite well and could fly inverted for as long as you wanted with complete directional control.
 

User27

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My answer is no, not really. Perhaps the question is why would an aircraft want to have no direct means of roll attitude control? I trained as a flying qualities engineer and can't see any reason why a designer would willingly give up the best roll control device we have invented in favour of using the secondary effect of the yaw control!! Although an ultralight might want to save weight, giving up the ability to operate in anything other than pretty calm conditions is a compromise too far for me. Birds just use a different systems, many have swing wings or can vary wing area - we don't have a weight efficient means to do that!! Increasing dihedral angle will make the aircraft want to fly in a straight line, requiring a more and more aggressive yaw to roll the aircraft (or larger and larger ailerons or slower roll rates). Properly designed ailerons just makes any aeroplane much more enjoyable to fly... Why else do we fly recreational aircraft?
 
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