BIOD43H3 Lecture Notes - Lecture 13: Cockatiel, Lift-Induced Drag
Feb.28th 2018
BIOD43 Lecture 13 Notes: Flapping Fight
• Oscillating wings relative to flight path introduces variation in direction of incident flow so as to
maximize lift and thrust
• Fastest flying velocity a Cockatiel can sustain is 13 m/s
• Center of mass (COM) moves in the direction of flight
• Lift vector is perpendicular to birds COM
• Upstroke wings are tilted slightly to produce net forward Thrust. This is similar to walking, when
stepping one foot in front of the other, a ground force acts against foot slightly pushing back-off
direction of travel.
• When bird is flying it experiences drag on its wing
• Pull of gravity on bird is greater than the Lift vector (Force of gravity> Lift force)
• By reducing Area of wing bird, the bird reduces the drag and lift acting on it
• It is difficult for cockatiel to fly at low-speeds, the plane of wing is much flatter. The movement
of air relative to wing is shifted (compared to faster flight). The Lit vector is shifted little which
produces less thrust.
Cost of flying?
• 3 components of drag that must overcome:
• Operating on wing:
• Induced drag- It is the power bird has to supply to induce proper airflow over wing.
• Icludes ides that Must proide ore poer at loer speeds
As forward speed increases so does lift
• Profile drag
- The pressure and skin friction (viscous) drag operating on the wings
• Parasite drag
-The pressure and skin factor drag operating on body
Both Profile and parasite drag increase with velocity
Induced power decreases with increasing speed
Flap-bounding= used at higher speeds, involves tucking wings in to eliminate drag.
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Document Summary
Biod43 lecture 13 notes: flapping fight: oscillating wings relative to flight path introduces variation in direction of incident flow so as to maximize lift and thrust. Lift vector is perpendicular to birds com: fastest flying velocity a cockatiel can sustain is 13 m/s, center of mass (com) moves in the direction of flight, upstroke wings are tilted slightly to produce net forward thrust. It is difficult for cockatiel to fly at low-speeds, the plane of wing is much flatter. The movement of air relative to wing is shifted (compared to faster flight). The lit vector is shifted little which produces less thrust. Cost of flying: 3 components of drag that must overcome, operating on wing: Induced drag- it is the power bird has to supply to induce proper airflow over wing: i(cid:374)cludes ides that must pro(cid:448)ide (cid:373)ore po(cid:449)er at lo(cid:449)er speeds. As forward speed increases so does lift: profile drag.
