The Configuration Of The Wing - Part -(2)

(A) Wing Support

As we know that a wing has to be rigid and strong by itself and in addition of it becomes heavy. So to overcome the problem of the weight, we can add external bracing but it also has a drawback which is the drag cause due to bracing.

 

The types of wing support are as follows:-

       (a) Braced:-   In this type of bracing  the wings are supported by the external structural members and also all the multi-planes are braced. Early Fokker Eindecker is the the example of this type.

          

             It's types:-

             

             (1) Wire Braced:-   Here along with the  struts, tension wires are also used to help to support the wing.

  

            (2) Strut Braced:-   In it hard and stiff struts are used to  support the wing. Also these struts may be one or more.

        (b) Cantilevered:-   This type of the wing is self-supporting. The complete structure is buried under the aerodynamic skin, which gives a clear appearance to the wing and low drag.

           

      (c) Flexible Wing:-                            

      

• Generally a flexible surface like a thin membrane is employed in it.  It includes many types like Rogallo wing, parafoil and most kites.
• An otherwise rigid structure may be designed to flex, either because it is inherently aeroelastic as in the aero-isoclinic wing.                                                      

    (d) Closed Wing:-   In this  type the two wing planes are joined at the tips in such a way that stiffens the  structure and reduces the aerodynamics losses at the tips.

        Some types of closed wing types are as follows:-

        (1) Box Wing:-   In these type of wings the upper and lower planes are joined by a vertical fin between their tips. The examples of planes that used the concept of Box Wing are Santos-Dumon's 14-bis, Dunne Biplanes, etc.

        (2) Joined Wing:-   It is a type of a tandem layout in which the front low wing sweeps back and the rear high wing sweeps forwards such that they join at or near the tips to form a continuous surface in a hollow diamond or triangle shape. The Ligeti Stratos is a rare example.

         (3) Annular Box Wing:-   It is also a type of box wing in which the fins curve continuously blending smoothly into the wing tips.

          (4) Rhomboidal Wing:-   It is a joined wing of four surfaces in just like a diamond arrangement.

(2) Wing Planform

      (a) Aspect Ratio:- It is the span divided by the average chord. It is a measure of how long the wing appears when it is viewed from the above or below.

                           

• Low Aspect Ratio:-   Generally, these have short and stubby wing. More efficient structurally and have higher instantaneous roll rate. This configuration is used by the fighter aircraft, as like the Lockheed F-104 Starfighter   

             

• Moderate Aspect Ratio:-   These are used very widely and we can say these are general purpose wings.      

• High Aspect Ratio:-   These type of wings are more efficient dynamically, have less induced drag and have long and slender wing. These are used by the high-altitude subsonic aircraft such as airliners like the Bombardier Dash 8.

          (B) Wing Sweep:-   In this configuration, wings may be swept back or may be swept forwards because of many reasons. Sometimes the degree of sweep is used to adjust the centre of lift when the wing cannot be attached in the ideal position.

• Forward Swept:-   The main benefit of this configuration is that it avoids the stall problems, the wing angles forward from the root, and has reduced tip losses but it requires even greater stiffness to avoid aero-elastic flutter as on the Sukhoi Su-47.                

• Swept Back:-   The wings sweep back rearwards from the root to the tip.

• Straight:- This is the most structurally-efficient wing, it has been common for low-speed designs since the very first days of the Wright Flyer.

           (C) Sweep Variation Along Span:-  The angle of swept may also be varied, or cranked along the span.

• M-Wing:- The outer section sweeps backwards and the inner wing section sweeps forward. This configuration was only studied, but  never applied on an aircraft.

• W-Wing:-   It is a reversed view of the M-wing and it was less studied than the M-wing and in the never used.

• Crescent:-   To obtain a best configuration out of the transonic shock delay and spanwise flow control, the wing outer section is swept less sharply than the inner section. It was used  on the Handley Page Victor.

• Cranked Arrow:-   It is aerodynamically identical to  the compound delta, but with trailing edge also kinked inwards. It was tried experimentally on the General Dynamic F-16XL.

         (D) Asymmetrical:-   

• Asymmetric Layout:-   Voss BV 141 had separate fuselage and crew nacelle offset on either side to give the crew a good field of view.

• Asymmetric Span:-   In it one wing was slightly longer than the other to help counteract engine torque. Studied on several Italian Fighters such as the Ansaldo SVA.

Oblique Wing:-   In it the one wing sweep backwards and the other forwards. 

By Devanshu Saini