Jumping and flying

1. Jumping and flying Movement in the air

2. Aim • jumping • gliding • powered flight • insects • birds

3. 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

4. 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

5. 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

6. 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

7. How far • maximum distance =2KE/ (mg) • =2 (kM)/(mg)=2(k/g) * (M/m) • as before distance not affected by body mass

8. 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 ??

9. Jumping in locusts • If we could jump as well, we could go over the Empire state building • elastic energy storage • co-contraction

10. Running jump • much higher/further • KE can be stored in tendons and returned during leap

11. Summary so far • Jumping is energetically demanding • muscle mass : body mass is most important • store energy in tendons if possible

12. Flying • gliding • power flight • hovering • How stay up? • Can nature do better than mankind?

13. Who flies? • insects • birds • bats • pterosaurs

14. 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

15. How does air speed up? • air slows down underneath because wing is an obstacle • air speeds up above wing • fixed amount of energy

16. Lift and vortices • faster /slower airflow • =circulation • extends above / below for length of wing • creates wake

17. Circulation • circulation vortex shed at wingtips

18. How much lift • lift increases with speed 2 • lift increases with angle of attack

19. 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

20. Fly optimally? minimum power maximum range

21. Can nature beat man?

22. Gliding • soaring in thermals • Africa: thermals rise at 2-5m/s • soaring at sea/by cliffs

23. 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

24. Bigger is worse • As bird size (l) gets bigger • mass  l3 • wing area  l2 • wing loading must go up  l • big birds need more wing area than little birds • harder to flap

25. 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

26. 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

27. 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

28. 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

29. Hovering flight • humming bird hovering • generates lift on forward and back stroke • as wings beat, vortices shed at end of stroke

30. Insect flight • flexibility of wings allows extra opportunities to generate lift • rotation of wing increases circulation

31. Insect flight lift • flexibility of wings allows extra opportunities to generate lift • fast flight of bee • downstroke • upward lift • upstroke bee move wing

32. Clap and fling • at top of upstroke two wings “fuse” • unconventional aerodynamics • extra circulation • extra force

33. Wake capture • wings can interact with the last vortex in the wake to catch extra lift first beat second beat

34. 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

35. 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

36. Thanks !