The Biomechanics of Flight A More Complete Multidisciplinary Perspective on Airplane Design

1
The Biomechanics of Flight-A More Complete
Multidisciplinary Perspective on Airplane Design

• John H. McMasters
• Technical Fellow
• The Boeing Company
• john.h.mcmasters_at_boeing.com
• and
• National Institute for Aerospace/ NASA Langley
  Research Center
• Hampton, VA
• October 20, 2003

Affiliate Professor Department of Aeronautics and
Astronautics University of Washington Seattle, WA
Invited Presentation
2
3 Hour Presentation Outline

• Background History and Context
• Some Basic Engineering Principles
• Structural Scaling
• Fluid Dynamic Scaling
• How big can a flying animal get ?
• Vertebrate Flight Evolution
• Pterosaurs
• Birds
• Some Applications
• Owls
• Aeronautical technology (including morphing
  aircraft)
• Teaching design (in a much more
  multi-disciplinary context)

3
The Biomechanics of Flight (and Morphing
Aircraft) as an Artifice to Connect Several Dots

• A need to revitalize the airplane business by
  creating a vivid positive vision of its future,
  as a means to
• Attract a next generation technical workforce
  that possesses a much broader multi-disciplinary
  and systems engineering perspective aided by
• Reform and enhancement of our technical education
  system (beginning at the elementary school level)
  to
• Attract and retain a student population
  (especially women) that more completely reflects
  the demographics of our society.

4
The Curriculum Vitae of an AerodynamicistJohn
H. McMastersTechnical FellowBoeing - Seattle
Once upon a time there was a mother duck and a
father duck who had five baby ducklings. The
first was a really ugly duckling who knew that
one day he would probably grow up to be a swan.
Well, the really ugly duckling never did grow
up he only matured into just a really ugly
duck. And so it goes (going on 87).
John at age 21
He had only one vanity, he thought he could give
advice better than any other person. Mark
Twain (writing about John McMasters)
5
The Traditional View of the History of Flight
Proliferation
Experimentation
Realization
Inspiration
6
A More Complete History of Flight
7
The Role of Aerodynamics in the Sex Life of the
Grasses and Trees(Wind Pollination in Setaria
geniculata and Poa sp.)

Coelocanths in a Fir (Pseudotsuga menziesii)
Forrest (Image by Aaron McMasters)
8
The Myth of the Bumblebee
Aerodynamicist Proves Bumblebees Cant Fly!
Seattle Muckraker
Guru remains in trance for 20 years ..without
food or drink
1..00 September 10
The tabloids do it to science again.
Elvis is Alive, Living in Argentina
A 380
News Flash. Britney Spears to run for
governor of New York
Giant fly devours jumbo jet . Hundreds missing
Astrophysicists find dark matter its cosmic cow
poop
9
The Actual Origin of the Bumblebee Myth
From A. Magnan, Le Vol Des Insects, Paris Herman
and Cle, 1934 (p. 8) Tout dabord, pousse par
ce qui fait en aviation, jai applique aux
insectes les lois de la resistance delair, et je
suis arrive avec M. SAINTE-LAGUE a cette
conclusion que leur vol est impossible.
10
Open Class Competition Sailplanes
Schempp-Hirth Nimbus 3 McMasters
Altostratus (Alex Aldott photograph, Soaring,
Dec. 1982) (Jack Olsen
painting, Soaring, Feb. 1981)
11
Schempp-Hirth Nimbus 3Open Class Sailplane
(circa 1983)Wing Span 24.6 m AR 37
Max. L/D 60 (flight test)
12
Altostratus 1 Open Class Sailplane(A
Speculative, Conceptual Solar-powered Design
Circa 1980)Wing span 25 m Max. L/D 100
(theoretical)
Solar cells
Griffith active boundary layer control airfoil.
Ref. McMasters, J.H. Flying the Altostratus,
Soaring, Feb. 1981, pp. 18-22.
13
5 meter Span Radio Controlled Model of an
Altostratus Sailplane A solar powered concept
airplane intended to achieve near 100 laminar
flow on both the wing upper and lower surfaces
with a resulting theoretical maximum L/D
approaching 100.
Fogel, Gary, Flying the Altostratus I, Soaring,
Nov. 2001 (following McMasters, J.H., Flying
the Altostratus I, Soaring, Feb. 1981)
14
A Cosmic View of Aviation History
Future of The World Economy ?
Mass extinction from space
Neil goes to the Moon
X
Insects
Dinosaurs Birds
?
Life Evolves On Earth
Boeing
Man Wright Bros.
Solar System Formed
Global climate change
Big Bang
Future of Earth ?
300 million years of flight
15
Boeing 777 Fifty Years of Progress
Boeing B-47 (circa 1947)
Boeing Model 387-80 707 prototype, circa 1956
16
Aeronautics Technology Progress
Theoretical Upper Bound

• Index of
• Performance
• (Measure of Progress)

Good
Digital microprocessor
Log scale ?
Possible Achievement
Jet engine Swept wings
?
Aluminum
Without Continued Major RD Effort
Speed, Range, Altitude, Operating Cost, Life
Cycle, etc.
Actual Achievement
- Increasing customer requirements -
Increasing regulatory stds. - Increasing
environmental concerns
1900 1950 2000
Historical Time
17

• Options and Opportunities
• Continue evolving current lines of development
  as long as a market exists for the results
• Schedule a breakthrough or an invention
  expand the range of the possible
• Start a whole new game where the gap between
  possible and actual is again very large
• All of the above !

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19
Various Ways to Create Wings From the Same Basic
Set of Bones in Vertebrates
Pterosaur
Bird
Human
Bat
20
Joel Grasmeyers Microbat 3Micro Air Vehicle
Attacked by a Seagull
A penny for size comparison
21
Pterosaurs 140 Million Year of Success(A
Natural Model of Cylindrically Cambered Rogallo
Wings)
Rhamphorhycoidae
Older stability configured sub-class.
Rhamphorhyncus sp.
Newer control configured sub-class (no tails).
Pterodactyloidea
Note Although they share a common ancestor,
pterosaurs are not dinosaurs. They existed
contemporaneously and also became extinct at the
end of the Cretaceous, 65 million years ago.
Pteranodon ingens (Wing span 7 m)
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The Relative Aerodynamic Efficiency of Conically
and Cylindrically Cambered Rogallo Wings
23
How Pterosaurs Really Worked Remains Controversial
Pteranodon ingens
More recent conjecture
Traditional model
24
Comparison of Humerus Bones from Large Flying
Vertebrates (Quetzalcoatlus and Argentavis)
21.0 m 15.5 m 11.0 m
Wing Span (m)
Pteranodon Quetzalcoatlus
Texas Pterosaur (Quetzalcoatlus northropi)
Humerus Length (cm)
Argentine Teratorn (Argentavis magnificens)
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The Texas Pterosaur (Quetzalcoatlus northropi)
Max. adult wing span 12 m ( 39 ft.)
California Condor
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The MacCready Robotic Replica of the Texas
Pterosaur Quetzalcoatlus northropi
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The Evolution of Birds
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The Possible Origin of Birds Within theTheropod
Dinosaurs (after Prum, 2003)
Microraptor gui ( 125 Mya)
Archaeopteryx lithographica ( 140 Mya)
Evolution of powered flight, and loss of hind
wings
Evolution of four feathered wings and gliding
Feathers ?
I personally doubt this.
Richard O. Prum, Nature, Vol.421, 23 Jan. 2003,
pp. 323-4
29
Tandem Wing Fliers
Microraptor gui Northern China 125 Mya
Rutan Proteus (circa the present) www.scaled.co
m
77 cm ( 30 in.)
V
Ref. Xu, et al., Nature, Vol.421, 23 January
2003, pp. 335-40.
A feathered analog to a flying squirrel?
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Playing Hopscotch(It All in the Arms and Legs)
32
One Possibility for the Origins of Bird Flight
A plausible (and probably testable) explanation
for a cursorial origin for the evolution of
flight in birds due to Phillip Burgers and Luis
Chiappe.
Ref. Burgers, P. and Chiappe, L.M., The wing of
Archaeopteryx as a primary thrust generator,
Nature, Vol. 399, 6 May 1999, pp. 60-2.
33
Options for the Evolution of Flight

• The arborealists are right flight evolved from
  the trees down (- except for insects?)
• The cursorialists are right ( for birds and
  bugs)
• The creationists are somehow right there is
  some divine engineer trying every possibility in
  no humanly discernable order
• Evolution is a lot more complicated than has been
  thought, and leads to numerous family bushes
  rather than simple family trees
• Times and circumstances change and not all
  experiments are successful, nor are all solutions
  to a problem durable.

34
The Transport Economy Index
(Energy Consumed per Unit Weight per Unit
Distance Traveled)
E/WR P/WV P P0 TV CM0.75 TV T/W E
-1 E L/D
100
Fliers
Walker Runners
Optimum Transport Economy Index (cal/g-km)
10 1 0.1
Machines
SUV
Swimmers
?
Good
10 6
1
106
Mass M (kg)
35
The Square-Cube Law Applied to Geometrically
Similar Animals
L characteristic length L2 area (surfaces
and cross sections) L3 volume (and thus
weights)
L
A B
C
How big ?
Z Y X
How small ?
36
Mass - Wing Area Relations for Flying Devices in
Comparison with the Square-Cube Law
103 10 -3
Wing Area S (m2)
M S3/2
1
M 15 S3/2
10 -3
10 6 1 106
Mass M (kg)
37
So, What is a Reynolds Number? Reynolds number
is one of those things engineers made up to make
them good conversationalist at dinner.We use it
to get dates. A Senior Boeing Engineering
Executive, (who shall remained unnamed) circa
1990
38
Typical Variation in Aerodynamic Efficiency
(Lift-to-Drag Ratio) with Reynolds Number
Std. Aero. E. textbooks
Smooth Model (Variable Boundary
Layer Transition Locations)
Large-Scale Laminar Flow Separation on Smooth
Models
20 10
Maximum Subsonic Lift-to-Drag Ratio
Rough Model (Fully Turbulent Boundary Layer)
Insect-like Wings
Sailplanes
Birds
0
Insects
Wind Tunnel Testing
Large Airplane Flight
103 104 105
106 107 108
Reynolds Number (based on average wing chord)
39
Comparison of Large Soaring Birds
Different Soaring Modes and Environments
Different Geometries
Wandering Albatross (Diomedae exulans)
California Condor (Gymnogyps californianus)
Albatross Condor Wing Span (m)
3.5 3.0 Wing
Area (m2) 0.72
1.5 Aspect Ratio 17
6 Mass (kg) 9.8 10 Wing
Loading (kg/m2) 13.6
6.6
40
Wing and Skull Comparisons of Large Birds
60 cm (23.5)
Argentine Teratorn (Argentavis magnificens)
California Condor (Gymnogyps californianus)
Merriams Teratorn (Teratornis merriami)
Wandering Albatross (Diomedae exulans)
41
How Large Can a Soaring Bird Become ?
5.5 7.3 m (18-24 ft.)
Argentine Teratorn (Argentavis magnificens) Miocen
e 7 Mya

California Condor
0 1
Scale (m)
Ref. Campbell, K.E., Jr. and Tonni, E.P. (1983)
Auk, Vol. 100, pp. 390-403.
42
Flight Muscle Mass as a Fraction of Total Mass in
Birds
Flight Muscle Mass MFM (kg)
Flight muscle mass (MFM) 0.25 M
Total Mass M (kg)
43
Power Requirements in Steady, Level
Flight (According to the Square-Cube Law)
Power P (watts)
Teratornis incredibilis (after H. Howard) (35 kg)
P M 65/57 (accounting for viscous scale effects
assuming a fully turbulent boundary layer)
Kori Bustard (20 kg) (after Pennycuick)
7/6 1.167 65/57 1.140
Pigeon
Mass M (kg)
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Gravity According to Newton(The Shrinking Earth
Hypothesis) For which there is currently no
shred of evidence - yet.
F k M m R2
m
Where F mutual force of attraction (or
weight of object of mass m) M mass of the
earth R distance between the centers of
the two masses K universal
gravitational constant
m
Rt Rn
Fn
Ft
Assume the Earth has been shrinking as it cools
since it first formed..
M
Thus If, say 100 my bp, Rt was 20 larger than
now (Rt 1.2 Rn), and M and m are constant over
time, the same object (m) on or near the surface
of the Earth would have weighed 31 less then
than it does now (Ft 0.69 Fn).
This example represents an average, almost
undetectable change in diameter of less than
three meters per century !
45
The perennial engineering question Well,
thats all very interesting I suppose
but..What do you DO with it ?
46
Bionics Process Flow
Nature Technology
Operational Design Requirements and Objectives
(DROs)
Organism (Plant/Animal)
Initial Baseline Machine
Physical Characteristics
Observe/ Deduce Operational Requirements
Observe/ Measure Physical
Characteristics
Evaluate Against DRO
Basic Knowledge (Physics Economics)
Evaluate/ analyze
Define Improvements Needed or Wanted
Synthesize (Engineer) Solution(s)
Borrow Concepts (not necessarily same hardware)

• Understanding
• How organism works
• What its devices do
• Limitations

Improved Baseline Machine ?
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Notes on the Wonders of Owl Wings and Feathers

• Owls are
• Highly evolved and specially adapted primarily as
  nocturnal predators, often flying in confined
  spaces
• Need to fly slowly and with a high
  degree of
• maneuverability
• Splendid examples of natural stealth technology
• Approach not detectable by prey
  while using highly
• developed bi-aural direction
  finding and night vision
• Note The owls adaptations to do these two
  things are often confused with each other. They
  turn out to be synergistic.

49
Owl Wings and Feathers Have Special (and
Sometimes Unique) Adaptations

• Some Basic Principles
• The noise generated depends theoretically on
• The fifth power of the relative speed between the
  flow and the object
• The inverse square of the distance between the
  object and a hearer (noise receptor)
• The details of the shape and size of the object
• The forces generated depend on
• The size of the object (primarily its surface
  area exposed to the flow)
• The square of relative speed (for a gliding bird
  not flapping its wings, the square of the flight
  speed)
• An index (force coefficient) dependent on the
  shape and attitude (e.g. angle of attack) of
  the reference axis of the object relative to the
  flight direction

50
Special Features of an Owl Wing
Combs on leading primaries Specialized form
of vortex generators for increased lift for slow
flight and enhanced maneuverability
Soft, serrated wing trailing edge Diffuses and
reduces high frequency noise
Velvety feather Surfaces Reduces both mechanical
and aerodynamic noise
51
Owl Wings and Feathers Have Special (and
Sometimes Unique) Adaptations contd

• To fly slowly (and thus with low noise) and
  maneuverably
• A wing of relatively large area for its body
  weight
• Special comb-like structures on the leading edges
  of the leading primaries that generate vortices
  that increase lift
• To reduce noise audible to their prey (and not
  interfere with their own hearing/direction
  finding)
• Feathers with a velvety surface texture reduce
  mechanical rubbing and rattle, and kill higher
  frequency air flow noise
• A soft and serrated wing trailing edge that
  diffuses and damps higher frequency components of
  air flow noise

52
Owl Wings and Feathers Have Special (and
Sometimes Unique) Adaptations

• The Silent Flight of Owls

Owl hearing range 100Hz - 20 kHz
Lower limit of prey hearing range
Owl bi-aural hearing range 3 - 6 kHz
Typical spectrum of sound generated by most
birds qualitative only
Sound Intensity SPL- sound pressure level
Owl noise spectrum
Mouse squeaks and leaf rattles
2
10
Sound Frequency kHz
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A California Condor (Gymnogyps californianus) in
a Glide

• Important Aeronautical Technology Incorporated
• In Birds
• Mission Adaptive Wing
• Active Controls/ Control
• Configured Vehicles
• Composite structures
• Damage Tolerant
• Structures
• Fully integrated System
• Design
• Advanced
• Manufacturing
• Techniques

55
The Very Variable Geometry of Bird Wings
Soar and Search
Stoop and Kill
56
Consequences of the Variable Geometry of a Bird
Wing on Gliding Performance

Horizontal Speed V
Vertical Speed (Sink rate)
0
57
How Much Morphing Is Enough ?
Tupolev Tu 160 Blackjack Bomber
58
Morphing Airplane Concepts A Taxonomy ?

• Static Morphing Several possible
  configurations from the same basic root stock,
  but once a choice is made you have to go with
  what youve got.
• Insects and anemophilous seeds
• Variable mass (water ballast in sailplanes)
• Dynamic Morphing Configuration changes as the
  situation or (sub-) mission changes.
• The usual mission adaptive wings (birds, F-111,
  F-14, B-1, etc.)
• Flying cars/roadable airplanes
• Flying submarines/submersible airplanes
• Operational Morphing - Either fixed or
  variable geometry platforms that may alter their
  capability by changing operational modes or by
  acting collectively.
• Colonial slime molds
• Birds (formation and flocking flight)
• Surface effects vehicles (wings in ground effect)

59
A Concept for a Practical Variable Thickness Wing
for a Light-Weight Composite Sailplane
Ref. McMasters, et al, Technical Soaring, Vol. 6,
No 4, 1981.
60
Pressure Distribution Comparisons for a Variable
Thickness Airfoil

-


61
Johns Party Favor Morphing Wing
Concept(Continuously variable span, area and
perhaps camber)
High speed (Small span and area)
Rear (Trefftz Plane) Views
Low speed/Long endurance (Large span and area
with increased camber?)
Probable maximum feasible wing span 30 cm.
Asymmetric extension provides roll control
John McMasters November 20, 2002
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A Whole Flock of UCAVs(The Formation Flight of
UCAVs Across the World in the Spring)
Cruise good endurance Attack high speed
Flight Direction (cruise)
beffective
b
63
Must All Transport Airplanes Look Pretty Much
Alike in Future
Boeing Airbus
64
Northrop B-49 bomber (circa 1948-49)
65
A Family of Non-Planar Wing ConfigurationsConstan
t wing span (b), area (S) and height-to-span
ratio h/b0.2
Total Drag(D) Dviscous Dinduced
Dcompressibility Dviscous
SwetV2f(CL) Induced Drag (drag due to lift) Di
k Lift (L)/span (b)2x I speed (V)2 k
theoretical wing span efficiency factor
In steady, level flight,


Lift (L) Weight (W)
b
Biplane k 0.74 X-wing k
0.75 Branched tips k 0.76 (pfeathers) Tip
plates k 0.72 Box biplane k
0.68
Joined wing k 0.95 C-Wing
k 0.69 Tip plated winglets
k 0.83 Winglets k
0.71 Dihedral k 0.97
h
Note For an optimally loaded planar wing of the
same span and area k 1.0
Aspect ratio b2 S
Treffetz plane analyses due to Prof. Ilan Kroo,
Stanford University (circa 1992).
66
A C-Wing Configuration for a 600 Passenger
Transport Airplane
A highly non-planar wing configuration ultimately
inspired in a proper bionic sense by the large
splayed pinion feathers of large land soaring
birds (e.g. vultures).
McMasters, J.H. and Kroo, I. M., Advanced
Configurations for Very Large Subsonic Transport
Airplanes, NASA CR 198351, Oct. 1996 also
Aircraft Design, Vol. 1, No. 4, 1998, pp.
217-242.
67
Some Configuration Options For Very
Large Commercial Transport Airplanes
Winged Watermelon (Flying Spud)
(Somewhat) Pregnant Seagull
Klingon Battle Cruiser
Whatever ??
???
68
Returning Again to an Era of Complete Airline
Customer Satisfaction
69
A 1250 Passenger Super Clipper
It may not be as fast as a Boeing 747, but if
the trip takes a little longer what does it
matter if there are so many ways to have such a
good time !
70
A 1250 Passenger Super Clipper
Crew of 70 including pilots, flight attendants,
musicians, mimes, etc.
Siegfried Roy on selected routes on
Thursdays Wayne Newton, always.
Piano Lounge
Ballroom
Jogging Track
101 bypass ratio Turbofans, 120,000 lbs. thrust
each
Shopping mall bowling alley
Wine bar with chamber music
Weight Room Sauna
Boeing Model 314 Clipper
Wing span 478 ft. Wing area 0.65 acres T.O.
Weight 2,547,000 lbs.
Boeing 747-400
To scale
From the desk of John McMasters (circa June 1993)
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A Few Conclusions

• Amazing progress has been made during the first
  century of powered human flight in terms of
  farther, faster, higher and we have far
  excelled all of natures fliers in these regards.
• On the other hand, we have yet to develop a self
  repairing airplane that can lay eggs and
  reproduce itself. Perhaps there is more
  potential in the development of cloning rather
  than morphing structural technology.
• Regardless of its utility, the study of the
  paleo-ecology of natural flight makes a grand
  hobby, encompassing life, the universe and just
  about everything elseIt provides some of the
  inspirational tent poles that keep our
  imaginations from collapsing around us.

72
Despite some recent evidence to the contrary. It
is highly premature to write the history of the
airplane business as an obituary !


Aerospace Engineer

World Events (9/11, etc.)
Please note that no beavers were actually harmed
during the making of this presentation
Note No beaver was actually injured in the
creation of this image.
73
The Nine Dot ProblemThe Origin of Out of the
Box Thinking(or a Paradigm for Paradigm
Shifting)
Problem What is the MINIMUM number of straight
lines required to connect the
nine dots shown without lifting the pencil
from the paper?
74
Solving the Nine Dot Problem
Basic Solution 5 lines Government required
solution 6 lines (5 lines to solve the problem

and one more to assure compliance)
75
Solving the Nine Dot Problem (2)
The Creative Rocket Scientists Solution 4 lines
76
Solving the Nine Dot Problem The Final Frontier
An 8-year Old Students Solution Transform the
nine dot problem
into a one dot
problem and jam
a pencil through it
(i.e. one line)
Yes, it is a line, 9 thickness of paper in
length.
Fold
Fold
Thanks to Dr. Paul B. MacCready Jr.
77
Opportunities in a Balanced Exploration of the
Knowledge Management Domain

• A balanced approach is needed.

Aware
What we know we know.
What we know we dont know.
Knowledge Re-use
Targeted Research
Potential big savings
Unknown
Known
Curiosity-based Research
Prospecting Hunting Searching
Traps Surprises Competitive Risk
What someone knows, but that we havent found
yet.
What we dont know we dont know.
See the attached Bibliography for a starting
point on the topic at hand.
Unaware
DARPA land
Originally developed by Dr. Lee Matsch Allied
Signal Aerospace and John McMasters under the
auspices of the Boeing initiated
Industry-University-Government Roundtable for
Enhancing Engineering Education IUGREEE in
1997-98.
78
Altrostratus I
Feb. 5, 2003 LaJolla, CA. John McMasters in the
office of Natural Selection, Inc. President,
Larry Fogel with the 1/5 scale model of the
Altostratus sailplane built by Gary Fogel and
Chris Silva. When painted properly, this model
will become part of the permanent display at the
new Smithsonian National Air and Space Museum
Annex which opens in 2004 at Dulles International
Airport in Washington, D.C. For further details
on the project see www.geocities.com/altostratus
sailplane
For those who have never seen a real airplane
with an aspect ratio 51 wing, the following
web site may be of interest www.eta-aircraft.de/