Aircraft Geometries I: Wing Parameters and Planform

• The lecture series is titled Aircraft Geometries I, for Semester I, by Dr. Maziar Arjomandi.

Wing Parameters for Study

• Wing location and planform are key geometric considerations.
• Wing size, described by chord and span, are important parameters.
• Aspect ratio and taper ratio are essential wing characteristics.
• Wing airfoil shape influences aerodynamic performance.
• Sweep angle and incidence angle affect stability and control.
• Dihedral angle and twist influence lateral stability.
• Lateral and secondary control surface positioning, size, and layout are important.

Wing Location on Aircraft

• Wing location can be low, mid, or high, influencing aircraft design and performance.
• Examples of various aircraft include:
  • Tupolev TU154.
  • Boeing 737.
  • Mallard.
  • F-16 Fighting Falcon.
  • C-17.
  • Falcon 2000.
  • G-222.
  • MIG-25 Foxbat.

Wing Planform Types

• Wing planform refers to the shape of the wing when viewed from above.
• Types of wing planforms:
  • Rectangular wing: Constant chord, low cost, very low speed, stall problem.
  • Linearly tapered: Variable chord, modern aircraft, low speed, high cost.
  • Elliptic wing: Variable chord, the best aerodynamic efficiency, very expensive.
  • Swept linearly tapered: Variable chord, modern aircraft, high speed, high cost.
  • Delta wing: Variable chord, supersonic speed, high cost.
  • High aspect ratio rectangular wing: Constant chord, low speed, high aerodynamic efficiency.
  • Low aspect ratio rectangular wing: Constant chord, low cost, low aerodynamic efficiency, good for models.

Wing Area and Geometry

• Key parameters for wing geometry include span (S), chord (C), and wing area (A).
• Wing area (A) is calculated using span and chord dimensions.
• Wing reference area is important for aerodynamic calculations.
• Examples of wing areas for different aircraft:
  • Wright Brothers Rectangle.
  • Space Shuttle Compound.
  • Boeing 747 Trapezoid.
  • F-18 (Blue Angels) Trapezoid.
  • Concorde Triangle.

Aspect Ratio and Other Geometric Properties

• Aspect ratio (A) is defined as b/c. It can also be expressed as b²/S. Another expression shown is 2b/(1+λ)
• Taper ratio (λ)is defined as Ct/Co, the ratio of tip chord to root chord.
• Planform area (S) is described as Co ((1+λ)b/2)
• Midspan chord: Co' = 2S / b(1+ λ)
• Tip chord is designated as Ctrip = λ * Co
• Mean aerodynamic chord (C) = (2/3) * Co * (1+λ + λ²)/(1+ λ)
• Mean aerodynamic chord position (Y) = b/6 * (1+2λ)/(1+λ)

Airfoil Characteristics

• An airfoil is the cross-sectional shape of a wing or blade.
• The mean camber line is the locus of points halfway between the upper and lower surfaces.
• The chord line is a straight line connecting the leading and trailing edges.
• Camber is the maximum distance between the mean camber line and chord line.
• Thickness is the maximum distance between the upper and lower surfaces.

Airfoil Examples

• Various airfoil designs include:
  • Wright 1908.
  • Göttingen 387 1919.
  • Bleriot 1909.
  • Clark Y 1922.
  • NACA series airfoils.
  • Joukowsky (Göttingen 430).
  • NACA 66(1)-212 1940.
  • NACA 747A315 1944, and more.
• The next lecture will be on Aircraft geometries II.