Aero II

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Aero II Lecture 29 Wing Modification III
J. E. Brandenburg EAS 3101 Spring 2007
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Agenda

• Historic Wing Innovations
• Thin airfoil approximation for finite camber
• Flaps and Slats

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Airfoil Geometry
Highly evolved systems were adopted to describe
wing geometries
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Fly by Wire Electric Control of Airframes in
WWII

• Control accomplished by simple pressure sensors
  and electro-mechanical sequencers ( delayers
  and relays)
• Stall warning accomplished by pressure sensors on
  wings
• Sequencers activated electric motors driving
  screw jacks to deploy wing extensions or move
  control surfaces
• Success of these technologies led to modern
  dynamically stable aircraft

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Electric Actuator
Based on worm drive or screw jack principle of
high force from small motor
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Unstable Airframes F-117
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WWII Wing Inovations
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Me 109
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Dauntless
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Dauntless Dive Flaps
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Control Surfaces
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Circulation
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Bernoulli Equation
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Camber Cont.
Camber is positive on front of wing and negative
on back
Camber term
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Biot-Savart Law
Effect of localized vorticity falls off as 1/r
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On Camberline

x
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Camber line is Streamline of flow

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Straight Camber Line Airfoil(symmetric)

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Coordinate Transform


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Analytic Case


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Analytic Case


?(x)
0
x
Most of lift is at front of the wing!
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Local Vorticity
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Lift Profile on Wing
Region of lowest pressure
Fast air
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Pressure Over Wing
Red marks low pressure
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For thin symmetric airfoil



CL
?
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Straight Camber Line Airfoilcambered)
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Effect of Finite Camber
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For thin cambered airfoil



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(No Transcript)
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Producing Camber
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Straight Camber Line Airfoil(symmetric)

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Straight Camber Line Airfoilwith flap depressed

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Effect of Flap Camber
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Flap Action For Small Angles
l
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Flap Designs
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Slat Designs
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Slats or Leading Edge Extension
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Effect of Slats on Camber
Zero at front of wing
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Slats and Flaperons
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Slats
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Stalls
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Slats Prevent Boundary layer Separation
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Flap and Slat Effect on Airflow
Slats do not add camber
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Leading edge extension
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Wing tips