Sep 2012 Lesson 2.2 Theory of Flight Wing Design.
-
Upload
harriet-poole -
Category
Documents
-
view
223 -
download
0
Transcript of Sep 2012 Lesson 2.2 Theory of Flight Wing Design.
Sep 2012Lesson 2.2
Theory of Flight
Wing Design
Reference
From the Ground Up
Chapter 2.1.2:
Design of the Wing
Pages 20 - 23
Introduction
• There are many different airfoil designs. The type of operation for which an airplane is intended has a direct influence on the design and shape of the wing for that airplane.
• Normally, an airplane designed for slow speed uses a thick airfoil and a thin airfoil is best for high speed.
Outline
• Camber & Planform• Angle of Incidence• Wingtips and Wing Fences• Wash Out• Flaps & Spoilers
Wing Design• Conventional Airfoils
– Thick, for stronger structure– Camber is farther rearward, which Increases lifting capability over
more of wing and decreases drag– For larger, slower aircraft (such as cargo planes)– Thickest at 25% chord
Wing Design• Laminar Flow Airfoils
– Usually thin– Leading edge more pointed and upper and lower surfaces nearly
symmetrical– For smaller, faster aircraft (such as fighter jets)– Thickest at 50% chord
Planform
• Planform – Shape of wing as seen from above
• Aspect Ratio – Ratio of wing span to Chord (or MAC)
• High Aspect Ratio creates more lift and less induced drag
Angle of Incidence
• Angle that wing is attached to fuselage
• Angle between wing and longitudinal axis (or the horizontal)
Longitudinal Axis
Longitudinal Axis
Angle of Incidence
Wing Tip Design
• Different wing tip devices disrupt vortices, thus decreases induced drag. Some devices: – Wing tip tanks– Wing tip plates– Droop wing tip– Winglets
Wing Fences• Small fin-like surfaces on upper surface of wing
• Control and straighten airflow, reduce wing vortices, and therefore reduce induced drag
• Provide better slow speed handling and stall characteristics
Wash-Out
• Wash-Out - Twist in the wing so wing tip has smaller angle of incidence than wing root
• Reduces tendency of wing to stall suddenly
• Wing tips stall last, so ailerons remain effective
Flaps and Spoilers• Slats - Airfoils on leading edge that pull out at
high angle of attacks. They help improve lateral control by smoothing out turbulent airflow
• Slots - Passageways in leading edge. At high angles of attack, air flows through holes smoothing out turbulent airflow
• Leading Edge Flap – Increase camber and increase lift
Flaps and Spoilers
Flaps and Spoilers
• Spoilers - Devices fitted into wing that increase drag and decrease lift
• Speed Brakes – Devices on wing or fuselage that increase drag
Flaps and Spoilers
• Flaps are high lift devices that increase the camber of the wing. Flaps give you:
– Better Take-off Performance– Steeper Approach Angles– Lower Approach/Landing Speeds
Next Lesson
2.3 - Theory of Flight
Airplane Axes
From the Ground Up
Chapters 2.1.3, 2.1.4:
The Axes of an Airplane, Stability
Pages 23 – 26