after Nachtigall, 1978

Un

‘Quasi-steady’ analysis(blade element theory)

n

drag = dragn

N

lift = liftn

N

total force

liftn dragn

liftn = ½ CL (n) Un2 S

dragn = ½ CD (n) Un2 S

wind tunnel

CL

CD

0

0.5

1.0

0 0.5 1.0

U

nCD

CL

1.3

0.8

0 1 2 3 4-1

0

1

2

3

drag coefficient

lift

coe

ffic

ient

locust

fc

fruit fly

f

c

crane fly

range needed to support flight

2D wing model at 45o angle of attack

leading edge

trailing edge

directionof motion

leading edge vortex

F

2

early late

early

late

increase fromleading edge

vortex

value required

For QSBE

Start of motion at low angle of attack

Start of motion at high angle of attack

leading edgevortex

RoboFly

DPIV and force measurement

DPIV and force measurement

2D translating flat plate

Karmanstreet

leading edgevortex

3D revolving flat plateat low Re

prolonged attachment

-9 0 9 18 27 36 45 54 63 72 81 90

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

angle of attack (degs)

forc

e co

effi

cien

ts

CL

CD

0 1 2 3

3.0

time (secs)

CD

CL

1.5

0

-1.5

3.0

1.5

0

-1.5

45o

-9o

-9o

45o

Ftrans

lift

total

dragU

flapping modelfruit fly

1.8

1.3

0.8

0 1 2 3 4-1

0

1

2

3

drag coefficient

lift

coe

ffic

ient

locust

fc

fruit fly

f

c

crane fly

uvs.

constant angular velocity (72 deg/sec)

constant forwardvelocity (0.157 m/s)

CD

0 1 2 3 4-1

0

1

2

3

CL

Translating model3D wing at 45o angle of attack, Re 110

David Lentink

Revolving motion3D model at 45o angle of attack, Re 110

David Lentink

downstroke

upstroke

1. delayed stall

1

2. rotational lift

2

3. stroke reversal

3

4. wake capture&added mass

4

down

up

stroke cycleupdown

1.5

1.0

0.5

0net force (10-5 N)

measuredforce

translationalquasi-steady

Altschuler, et al., 2005 PNAS

Dear Prof. Dickinson, July 28, 2006

I report on aviation for The Wall Street Journal and wonder if I could trouble you for a professional judgment.

Some entrepreneurs attempting to build a large commercial aircraft with small flapping wings have approached me to write a story about their project, and I'm trying to get a sense of whether their idea is at all realistic. They say their design is based, in part, on your research and development work. But obviously there is a huge difference between simulating a tiny insect and building a 100-passenger aircraft. The company is called JCR Technology, in case you have come across them. Their website, which so far seems only to be in French, has information about their design and some computer-graphic simulations.

Would you or someone in your lab have a few minutes to look at this and assess whether it is realistic to develop or simply to far-fetched? I would be happy to call to discuss your work more, and how it has prompted this idea.

Best regards, Dan Michaels

http://www.jcrtechnology.com

http://www.jcrtechnology.com

Integrative Approach

central nervous system

musculoskeletal system

motorcommands

dynamics& environment

kinematics & forces

Behavior

sensory systems

sensory feedback

olfaction

mechano-sensory

vision

sensory system of flies

Each wing stroke, the fly’s brain integrates input from 15,000 cells.

Wing Sensors (1000 cells)wing loading and contact

Halteres (900 cells)angular rate gyroscope

Antennae (2000 cells) olfaction, hearing, airspeed

Eyes (8800 cells)image & optic flow sensor

Ocelli (300 cells)light-based orientation

0.5 mm

Tammero&Dickinson, JEB 2002, Mark Fry, Ros Sayamen

1m

infrared light

infrared sensitive cameras

fabric enclosure

10 sec-1200

1200

0

angu

lar

velo

city

(o s

-1)

5000 frames/sec, 150 msec duration

top viewside view side view

visualfeedback

50% 50%~90onu

mbe

r

0

50

25

0 +90-90saccade angle

Saccades are triggered by visual input.

Tammero&Dickinson, JEB 2002a

~90o

flight arena

“fly’s eye view”

Tammero&Dickinson, JEB 2002a

Flies turn away from expansion.

wingbeatanalyzer

LED display

angular velocity

of stripe

gain

left- right stroke

amplitudefly

IR diode

‘closed-loop’ flight simulators

MichaelReiser

Stripe Fixation

fixation/expansion

rightleft center

summary of expansion reflexes

musculoskeletalmechanics

upstroke musclesdownstroke muscles

power muscles

b1 (first basalar)

steering muscles

wingmotion

b1

50 ms

phaseadvance

phasedelay

steering muscle control

aerodynamics

high speedcamera

IR LEDpanel

flightpath

visualtarget

30 degs

1) increase instroke amplitude

2) tilt ofstroke plane

0.25 1.0

yaw torque (10-8 Nm)

kinematics changes during saccades

left right

counter-torque to stop turning

What triggers counter-turn?

torque to turn

mechanosensoryfeedback

IR camera

CPU

magnet

magnet

LEDarena

mirror

N

S

N

S

magnetic tether

5x10-9 nNm

400 os -1

100 ms

torque withrigid tether

angular velocitywith loose tether

‘loose’ saccades vs. ‘rigid’ saccades

eyeshalteres

pitch

Coriolisforce

sensorarrays

halteres

time (ms)0 100 200 300 400 500

orientation(deg)

0

50

100

150

stimulus

fly

rotation withrotation against weighted haltereablated haltere

haltere feedback shortens saccades

|am

plit

ude|

(de

g)

0

10

20

30

40

50

60

normal

,

rotationwith fly

rotationagainst fly

mass onhaltere

no haltere

***

halteresensors

wing sensors

steering motor neuron

phaseadvance

phasedelay

summary of haltere reflex

steering motor neuronwing input

delay

haltere input

advance

Amir Fayyazuddin

visual expansion triggers saccade

small change in wing stroke accelerates

animal

halteres detects rotation and trigger

counter-turn

fly continues on new heading.

working hypothesis