Bird Adaptations for Flight

Covering of the wings are light smooth feathers

1.Reduces the force of weight

2.Reduces the force of drag

Have beaks instead of boney jaws and teeth

1.Reduces the force of weight

All flying birds have an enlarged breastbone called a sternum for flight muscle attachment

1.Aids in the force of thrust

The bodies of birds are streamlined

1.Reduces the force of drag

Light bones. Filled with air sacs and thin, tiny crosspieces to make bones stronger

1.Reduces the force of weight

Rigid skeleton to provide firm attachments for powerful flight muscles.

1.Aids in the force of thrust

Planes have similar lightweight, streamlined, rigid structures for flight

Flight styles

Maneuverability - wren, stunt plane

Speed - falcon, fighter jet

Carrying loads - pelican, cargo plane

Soaring - condor, glider

Lift

SpeedShape of the wing

wing area bernoulli effect coanda effect

Angle of attack Newton’s third law of motion

Wing area

Increased speed along a larger wing area creates a longer path of air reducing air pressure creating more lift

Larger wings produce greater lift than smaller wings. To compensate, smaller wing birds/planes need to fly faster to maintain the same lift as larger wings going faster

Question – A light glider with large wings. Does it have to go fast or slow for lift?

Question – A heavier jet with small wings. Does it have to go fast or slow for lift?

How can you tell how fast a bird/plane must fly to maintain lift?

By WING LOADING. – divide the weight by the wing area

A smaller wing load number tells you the bird/plane can fly slower while still maintaining lift.

Do thinking lab page 737

A smaller wing load number tells you the bird/plane is more maneuverable.

Aspect ratioFound by dividing wingspan by average width.

Wings with high aspect ratios have greater lift and less drag. Low aspect ratio wings can turn more quickly and are more maneuverable.

Obtaining thrustGravityFlapping wings

1. Gliding 2. Fast forward flight 3. Slow forward flight 4. Combination of the three

Running

Gliding

Birds with high aspect ratio can glide or soar almost motionless. They generally nest high on trees or ledges. And begin their thrust by jumping from their ledge.

Gliding continued

Ex: going down a ramp – gravity gives the forward thrust

To stay up for a long time, the angle between flight path and horizontal ground must be small, which reduces thrust. So drag force must be small.

Hence, long skinny wings have high aspect ratio.

Fast Forward Slow Forward Flight FlightWings move up and downLarger birdsSlow moving wingsPage 746

Wings move from side to sideSmaller birdsFast moving wingsPage 747

Combination

Most birds go between gliding and fast forwardLarger birds – gliding, fast forwardSmaller birds – gliding, slow forwardTake off – slow forwardFlight – combinationLanding – gliding, slow forward

Obtaining height

Bernoulli, coanda, speed, angle of attackThermals – upward flowing wind by convectional currentsUpdrafts – land features pushes up wind