Bird flight
- Created by: ValentineDevil
- Created on: 11-03-19 23:30
View mindmap
- Bird Flight
- Physics of flight
- Aerofoil
- Forward thrust, backward drag, upward lift, downward weight
- Can assume shape, but some more membranous as in bats and flying fish
- Retaining control
- Low speed, need steeper angle = turbulence on upper wing surface that reduces lift
- Deploying alula restores laminar air flow over the wing and minimises turbulence and increase lift
- Tail
- Act as rudder (steer); air brake
- larger= improves manoeuvrability; smalll reduces ability for sharp turns
- Weight-reducing Adaptations
- Thin, hollow bones; extremely light feathers; skin gland /teeth/heavyjaw/tail verts elimination....bone fusion in pectoral and pelvic girdles and vert columb
- Branching air sacs, oviparity, atrophy of gonads
- Power-increasing adaptations
- Endothermy; heat conservation plumage; energy-rich diet; rapid and efficient digestion; high blood glucose; four-chambered heart and double circulation; high pressure circulation; efficient respiratory; breathing movements synchronised with wing movements; high metabolism
- Aerofoil
- Types of wings
- Elliptical wings
- Short, road, low aspect ratio
- Turbulence created by broad tip of wing offset by slotting primary feathers that creates lift
- Traded aerodynamic advantages of longer wing for manoeuvrability of a shorter one
- Less lift but reduced wing loading
- Flight speeds are relatively low
- E.g. sparrow, blackbird, grouse, thrush, crow
- High-speed wings
- Tapered, pointed and often swept back
- Primary feathers have little slotting
- High aspect ratio but energetic expensive- flapping is necessary to generate lift
- Flight is high speed and control is crucial
- e.g. swift, falcon, duck, sandpiper, tern
- Slotted high-lift wing
- E.g. eagle, buteo, stork
- Soaring
- Broad wing with deep camber and prominent primary slotting- broadness catch rising air
- Moderate aspect ratio
- Slow flight speed
- High-aspect ratio wings
- e.g. albatross, gannet and gull
- Soaring
- Long, thin wings but proximal wing is elongated so provides large area to generate a lot of lift
- Efficient at relatively high air speeds
- Untitled
- Elliptical wings
- Structure of wings
- Pterosaur
- Extended IV digit and skin flap
- Bat
- Extended digits except first (thumb)
- Wings more broad than pterosaurs
- Bird
- Reduced digits and feathers
- each feather is an aerofoil
- Modified keratinised scales
- Primary and secondary feathers/covers. Alula and marginal covert feathers.
- great control over aerofoil
- Pterosaur
- Types of flight
- Powered flight
- Less pressure pushing down.... lifts up!
- Shape of aerofoil changes
- Use own musculature
- Most use this, not all but especially for take off (may employ other strategies for staying in the air
- Keel is attached to sternum- sight of muscle attachment
- Contraction, humorous goes down
- Hand-wing: bowing allows for musculature (increases control)
- Expensive, so flightlessness favoured,
- Downstroke: primaries/secondaries stiffen, form a link on this downstroke that little wind can get through
- Pushes wrist and wing forward to provide thrust and lift
- Wing moving faster than the bird forcing the air upwards towards the rear of the bird
- Primary feathers twist, to reduce angle of attack and minimise risk of stalling (otherwise too much resistance to air flow and bird could stall)
- Upstroke: wings twist, feathers part which allows wind between them
- Allow no wasted energy to move up
- Pulls wrist and wing backwards and upwards
- Figure eight
- Wing loading
- ratio of body weight to wing area
- Smaller birds: lighter wind loadings than larger birds
- Wing loading imposes the ultimate limit on body size in flying animals
- As bird size increases, volume increases faster than surface area
- Maintain similar loading? = wings too large to control
- Smaller birds: lighter wind loadings than larger birds
- Depends on flight style (e.g. soaring raptors have low wing loading for size)
- ratio of body weight to wing area
- Powered flight
- Variation in flight style
- Powered (flapping): Elliptical or high speed wings
- Gliding (losing altitude) Any wing shape
- Non-powered (no flapping or thrust)
- Soaring (gliding with no altitude loss)
- Static soaring (bird projected upwards by moving air): Slotted high-lift wings
- Thermal soaring (on rising thermals)
- Slope soaring (on rising air along a slope)
- Dynamic soaring (bird uses wind speed gradients): high aspect ratio wings
- Static soaring (bird projected upwards by moving air): Slotted high-lift wings
- Soaring (gliding with no altitude loss)
- Powered (flapping): Elliptical or high speed wings
- Physics of flight
Comments
No comments have yet been made