AAW Active Aeroelastic Wing

[Gameness]

Hi everybody! Has anyone ever heard of AAW Active Aeroelastic Wing?
It is a high-tech adaptation of the Wright Brothers rudimentary "wingwarping"
approach to aircraft flight control.
I'd like to know if someone has documents about it, or if has built a model with this control system.
BTW, what would be a good airfoil to try this system?

Please, see the PDF file for details.

http://www.nasa.gov/centers/dryden/pdf/120314main_FS-061-DFRC.pdf

[b36roxs]

as of now i have not seen any models with it incorperated but if i get the sponsership from my local hobby shop ill be sure to include it in my rc aircraft systems and airframe research :)

[eflightray]

Errr, .....birds?

[makarth]

Hi everybody! Has anyone ever heard of AAW Active Aeroelastic Wing?
It is a high-tech adaptation of the Wright Brothers rudimentary "wingwarping"
approach to aircraft flight control.
I'd like to know if someone has documents about it, or if has built a model with this control system.
BTW, what would be a good airfoil to try this system?

Please, see the PDF file for details.

http://www.nasa.gov/centers/dryden/pdf/120314main_FS-061-DFRC.pdf

it would be hard to replicate what nasa did with the full-scale. The idea is that they are playing with a nifty property of most metals' elasticity. metals can stretch bend and flex and return to there originally crystallized shape so long as the stress never crosses what's call "modulus of elasticity"(measured in stress/distance). The sole reason why steel is so versatile is because it has a high modulus of elasticity. Ever wondered why you can put 2200lbs (1.1 tons) of concrete in your 1/2ton pick-up and it it sags bends and flexes but doesn't break or stay drooped when you remove the payload? it's because of that property. the point in which the frame of the truck begins to sag may be 1/2 ton but the modulus may be way above 2 tons and so anything under 2 tons wont cause any damage. HOWEVER this does not take into account of dynamic forces of driving... this is a purely static example meant as a metaphor....the frame's modulus is probably more like 10 to 12 tons because when you hit a bump you cause an acceleration force greater then earth's (>1g) multiplying the payload

since i got that out of the way....

this issue becomes scale. 100ft of steel may be able to flex 1ft. So based on this made up fact i just said (for metaphoric reasons again) 1 ft of the same steel can only flex a 100th of a foot. woods distance variable of modulus (balsa and ply) may be enough to absorb the shocks and stesses of some serious 3D flying but if you couple that with internal flexing you might be asking for trouble (wing clapping).

now to side on actually making this happen. I love the concept of warp wing controls and i honestly can say that its the future of control surfaces. So in light of that... my approach would be to embed a servo inside the wing (to an outer wing rib) and anchor the other end to the spar of the wing (assuming the spar is design to be at the center of rotation for the wing). When the servo moves to roll the aircraft, it will turn one of the wing ribs. If you have a secondary spar that interconnects the ribs but is far less rigid then the support spar, then the primary rib that is connected to the servo will move the most pulling the next rib to move with it (but less) and then that rib in turn pulls the next rib down (but less) and so on and so forth. the primary spar could be an aluminum tube like the larger 3d aircraft have and the secondary spar could be a larger version of those cheap carbon fiber sticks for the foamies. Keep in mind that a little goes a long way with this control scheme and if you do go down this road keep a back-up channel of servos for traditional ailerons.

[JetPlaneFlyer]

metals can stretch bend and flex and return to there originally crystallized shape so long as the stress never crosses what's call "modulus of elasticity"(measured in stress/distance).
I believe you mean 'elastic limit' a.k.a. 'yield stress' This is the stress (force/area) above which permanent deformation occurs.

Modulus of elasticity on the other hand is a measure of stiffness = stress/strain

Steve

[makarth]

I believe you mean 'elastic limit' a.k.a. 'yield stress' This is the stress (force/area) above which permanent deformation occurs.

Modulus of elasticity on the other hand is a measure of stiffness = stress/strain

Steve

yes but i was trying to encompass the entire stress curve not just the point it falters. elastic limit is a point on the graph of "modulus of elasticity". But i worded somethings wrong.

[JetPlaneFlyer]

yes but i was trying to encompass the entire stress curve not just the point it falters. elastic limit is a point on the graph of "modulus of elasticity". But i worded somethings wrong.

The curve you are referring to is called the stress-strain curve. Stress is plotted on the vertical axis and strain (extension/original length) on the horizontal. The slope angle of the linear part of the graph gives modulus of elasticity in tension, a.k.a. 'Young's Modulus'.

I do agree with you that Aeroelastic wings would be incredibly hard to reproduce on a model. Unlike the early wing twisting aircraft (e.g Wright Brothers aircraft) the NASA F-18 wing actually used aeodynamic force to twist the wing (not the control actuators). There must be an incredibly fine line between a wing flexible enough to twist due to aerodynamic forces and one that flutters. It would also be tricky to make sure there was enough twist for adequate control at low speed (where aerodynamic twist force is low) without being massivly over sensitive or result in structural failure at high speed.

[ghoti]

Is the Carbon Falcon by acesim.com/rc anywhere close?
Bill

[JetPlaneFlyer]

Is the Carbon Falcon by acesim.com/rc anywhere close?
Bill

Not really.. The carbon falcon uses mechanically (i.e. servo) driven wing warping, similar to the Wright Flyers. the Aeroelestic wing uses aerodynamic force to twist the wing.

[Szymon Bartus]

It's worth to read this post on Paul Naton's blog:
http://glidefast.typepad.com/glidefast/2006/10/the_future_of_s.html#more
Unfortunately just one link is currently working...