Flexsys

Discussion in 'Hydrodynamics and Aerodynamics' started by Doug Lord, Jul 30, 2014.

  1. Doug Lord
    Joined: May 2009
    Posts: 16,618
    Likes: 305, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

  2. upchurchmr
    Joined: Feb 2011
    Posts: 2,874
    Likes: 89, Points: 48, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    A similar system was installed on a F-111 about 20 years ago.
    At that time the system was very heavy, and did not demonstrate the flexing surface at the end of the control system to the fixed trailing edge.

    Without some information on the installed weight, the method of actuation, and the cost you better just think of this as a good general idea, waiting for an application where it can be afforded.

    A college student patented a shape morphing actuator about the same time. Unfortunately it was based on a lead compound which could not take the strain that wings normally fly under - so it had no flight application (actually on a military fighter).

    Can you provide some examples of the Moth "shape morphing" application?

    For sailing application there was an application for a rudder in which a 3 part foil was used to reduce drag and reduce input force required. The rudder was in an AYRS publication - AYRS #79 Rudder Design, page 79. I think it is still available to order. It would have looked like a "shape morphing" foil if they had of covered the joints with a thin glass skin so it looked solid. I made a model copying it but did not find the skin coating I wanted to make it look smooth and long lasting.

    The other issue is defining a deflected section shape that optimizes lift/ drag for whatever you are trying to accomplish. Not being an aerodynamacist that part was always beyond me.

    This idea would be great for a shape that would allow a change from low lift low drag to high lift low drag, or even high lift/ high drag centerboard, rudder and foil
     
  3. Doug Lord
    Joined: May 2009
    Posts: 16,618
    Likes: 305, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Moth

    The thing I remember was sent to me from a guy in Switzerland. I may have posted more in the Moth thread but I don't have time to look tonight. So here is the picture of the flexible flap end allowing a partial span flap(like I used on my Test Model) to have a "solid state" connection to the foil to eliminate drag associated with the defected flap:

    click-
     

    Attached Files:

  4. upchurchmr
    Joined: Feb 2011
    Posts: 2,874
    Likes: 89, Points: 48, Legacy Rep: 579
    Location: Ft. Worth, Tx, USA

    upchurchmr Senior Member

    Similar to what I had in mind for the flexible material.
    But, I could only find something suitable (material choice) in 55gal drums. Not appropriate to my pocket book for a one off test.

    And I think it will tear with as much deflection as is illustrated.
    Also I wanted to smooth out the hingeline surface joint.

    Seems easier to run the hinge line to the tip. I don't know about the actual drag impact, of course. Testing will tell, and probably no one will give us that information. Knowledge is power and money.
     
  5. Doug Lord
    Joined: May 2009
    Posts: 16,618
    Likes: 305, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Part of the problem with my Test Model main foil is its thinness and the flex that makes possible. If the foil flexes with a full span flap. the flap will either jamb or hit a "bump" every time it goes past neutral. I have a Moth mainfoil/daggerboard and hit has a distinct bump when it's heavily loaded.
     
  6. Eric Sponberg
    Joined: Dec 2001
    Posts: 2,002
    Likes: 205, Points: 73, Legacy Rep: 2917
    Location: On board Corroboree

    Eric Sponberg Senior Member

    It is interesting in the video, and as you probably know from reading flight history, that the Wright Brothers' flexible wings were full twisting wings, without hinged flaps or ailerons. The WBs modeled their wings fully on birds' wings. The feature in the video, however, Flexsys, is basically still the hinged foil technology but just covered with a flexible skin. The technology does not flex the entire wing, as the WBs plane did, and as birds do. So, this is only a halfway step back toward the original flexible wing idea. We have yet to see a fully flexible wing.
     
  7. Skyak
    Joined: Jul 2012
    Posts: 1,194
    Likes: 25, Points: 38, Legacy Rep: 152
    Location: United States

    Skyak Senior Member

    This does not strike me as that much of a breakthrough. Composites can be designed with highly asymmetric properties -nothing new there. If anything there has been an improvement in matrix adhesion to the stiffening material.

    I also somewhat doubt that the flapless wing will be the next big improvement in airplane efficiency because of the need for multi-element wings on takeoff and landing. You need slots to get the high lift for takeoff at low speeds.

    The moth application is much more sensible. Consistent low angle of attack. Great performance sensitivity to drag reduction. No severe environment to contend with. No loss of life from failure. I predict it will show up soon and dominate.
     

  8. Nick_Sinev
    Joined: Aug 2014
    Posts: 63
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Sydney

    Nick_Sinev Junior Member

    Lots of wariants available:

    http://soft-wing.ch/en
    http://www.omerwingsail.com


    My proposal:

    [​IMG]

    The profiile is based on the combination of a circle (leading edge) and a quadratic parabola. I have reasons to think that cubic parabola for this task could do better, but I was trying to compare my ideas with NACA symmetrical profiles, which are based on quadratic parabolas.
    The circle touches the parabola at the point with the same curvature radius.

    The roller can move to the other side of the wing when tacking.
     
    Last edited: Aug 31, 2014
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.