Transcript Powerpoint slides (York campus only)

Jumping and flying
Movement in the air
Aim
 jumping
 gliding
 powered flight
 insects
 birds
References
 Schmidt - Nielsen K (1997) Animal
physiology
 McNeill Alexander R (1995) CD Rom
How Animals move
 Journals & Web links: see:
http://biolpc22.york.ac.uk/632/movelectures/fly/
 Extra reference:
 Videler, J (1993) Fish swimming Chapman & Hall
Jumping
 What limits how far we can jump?
 At take off have all energy stored as KE
 conversion of kinetic energy to potential
(gravitational) energy
 KE = ½ m v2
 PE = mgh
How high
 depends on KE at take off
 PE = KE therefore mgh = ½ mv² or gh = ½ v²
 If muscle is M, let work done be kM
 mgh = kM or h =kM/(mg) = (k/g)*(M/m)
 If same proportion of body is jumping muscle,
height should be the same
 no effect of mass on how high you jump
 neglects
air resistance
How far do we go?
 depends on take off angle
 d = (v² sin 2a) /g
 jumping.xls
 maximum at 45o
 Sin
90 = 1
 d = v2/g
How far
 maximum distance =2KE/ (mg)
 =2 (kM)/(mg)=2(k/g) * (M/m)
 as before distance not affected by body mass
Alice
Daddy
age
8
??
mass
35kg
87kg
distance
1.16m
??
How long to take off?
 depends on leg length
 time
to generate force is 2s/v
 for long jump, time = 2s/(g*d)
s
is leg length, d is distance jumped
 bushbaby 0.05 to 0.1s
 frog 0.06s
 flea 1 ms
 locust ??
Jumping in locusts
 If we could jump
as well, we could
go over the
Empire state
building
 elastic energy
storage
 co-contraction
Running jump
 much higher/further
 KE can be stored in tendons
and returned during leap
Summary so far
 Jumping is energetically demanding
 muscle mass : body mass is most important
 store energy in tendons if possible
Flying
 gliding
 power flight
 hovering
 How stay up?
 Can nature do better than mankind?
Who flies?
 insects
 birds
 bats
 pterosaurs
Lift
 why don’t birds fall due to gravity?
 where does lift come from?
 speed
up air
 Bernoulli’s Principle
 Total energy =
pressure potential energy +
gravitational potential energy +
kinetic energy of fluid
How does air speed up?
 air slows down underneath
because wing is an obstacle
 air speeds up above wing

fixed amount of energy
Lift and vortices
 faster /slower
airflow
 =circulation
 extends above /
below for length of
wing
 creates wake
Circulation
 circulation vortex shed at
wingtips
How much lift
 lift increases with speed 2
 lift increases with angle of attack
So to fly…
 we need to move through the air
 use PE to glide down
 as
go down, PE changed to KE
 use wings to force a forwards movement
Fly optimally?
speed
Profile power
power
Induced power
Total power
constant
energy/distance
minimum power
maximum range
Can nature beat man?
Gliding
 soaring in thermals

Africa: thermals rise at
2-5m/s
 soaring at sea/by cliffs
Bigger is better?
 big wings act on more air
 called
lower wing loading
 long thin wings have less induced
power
 called
aspect ratio
 more economical,
but have to fly
faster
Bigger is worse
 As bird size (l) gets bigger
 l3
 wing area  l2
 wing loading must go up  l
 big birds need more wing area than little
birds
 mass
 harder to flap
Summary so far
 Jumping is energetically demanding
 muscle
mass : body mass is most important
 store energy in tendons if possible
 Flying involves generating lift
 gliding
 use
PE to get KE to get speed to get lift
Flapping flight
 large birds fly continuously
 down
stroke air driven down and back
 up stroke
 angle
of attack
altered
 air driven
down and
forwards
 continuous vortex wake
Discontinuous lift
small birds with rounded wings
lift only on downstroke
 vortex ring wake
 http://www.biology.leeds.ac.uk/
staff/jmvr/Flight/modelling.htm
Bounding flight
 glide, flap, glide, flap,
 flap - several times, then glide
 full muscle power would make bird climb
 more efficient to use muscle at best
shortening rate
Hovering flight
 humming bird hovering
 generates lift on forward and
back stroke
 as wings beat, vortices shed at
end of stroke
Insect flight
 flexibility of wings allows extra
opportunities to generate lift
 rotation of wing increases circulation
Insect flight
 flexibility of wings
allows extra
opportunities to
generate lift
 fast flight of bee
 downstroke
 upward
 upstroke
lift
lift
move wing
bee
Clap and fling
 at top of upstroke two wings “fuse”
 unconventional
aerodynamics
 extra circulation
 extra force
Wake capture
 wings can interact with the last vortex in the
wake to catch extra lift
first beat
second beat
Summary
 Jumping is energetically demanding
 muscle
mass : body mass is most important
 store energy in tendons if possible
 Flying involves generating lift
 gliding
 use
PE to get KE to get speed to get lift
 flapping propels air
 insects often have unconventional
aerodynamics
Exam papers…
 Neuroscience (i): Matsuda K, Buckingham SD, Kleier D, Rauh JJ,
Grauso M, Sattelle DB. (2001) Neonicotinoids: insecticides acting on
insect nicotinic acetylcholine receptors Trends Pharmacol Sci. 22:
573-80
 Neuroscience (ii): Cho, W, Heberlein U, Wolf, FW (2004)
Habituation of an odorant-induced startle response in Drosophila
Genes, Brain, And Behavior 3: 127-137 [paper copy here]
 Muscle: Kappler, JA; Starr, CJ; Chan, DK; Kollmar, R Hudspeth, A
J (2004) A nonsense mutation in the gene encoding a zebrafish
myosin VI isoform causes defects inhair-cell mechanotransduction
Proc Natl Acad Sci U S A. 101:13056-61
 Movement: Prestwich, KN & O'Sullivan, K (2005) Simultaneous
measurement of metabolic and acoustic power and the efficiency of
sound production in two mole cricket species (Orthoptera:
Gryllotalpidae) J exp Biol 208, 1495-1512
Thanks !