1. Case Study - very large transport airplane Airplane Design: Past, Present and Future – An Early 21st Century Perspective
John H. McMasters
Technical Fellow
The Boeing Company
and
Affiliate Professor
Department of Aeronautics and Astronautics
University of Washington
Seattle, WA
April 2007
Ed Wells Partnership Short Course
Based on:
American Institute of Aeronautics and Astronautics (AIAA) & Sigma Xi Distinguished Lectures &
Von Kármán Institute for Fluid Dynamics Lecture Series: “Innovative Configurations
for Future Civil Transports”, Brussels, Belgium June 6-10, 2005

2. Notation and Symbols Used
A Area (ft.2, m2)
a Speed of sound (ft./sec., m/s)
AR Aspect ratio, b/č = b2/S
b Wing span (ft., m)
č Average wing chord (ft.,m)
CF Force coefficients (lift, drag, etc.) = F/qS
Cℓ Section (2D) lift coefficient
CM Moment coefficient = M/qSĉ
Cp Pressure coefficient = Δp/q
D Drag force (lb., N)
E Energy (Ft.-lbs., N-m)
e “Oswald efficency factor”
ew Wing span efficiency factor (= 1/kw )
F Force (lift, drag, etc.) (lbs., N)
H Total head (reservoir pressure)
I Moment of inertia
kw Wing span efficiency factor (= 1/ew)
L Lift force (lb., N)
ℓ Length (ft., m)
M Mach number (V/a)
M Mass (kg)
M Moment (ft. lbs., N m)
P Power (ft.-lbs./sec., N-m/sec.)
p Static pressure (lbs./ft.2)
q Dynamic pressure (lbs./ft.2) = ½ρV2
R Range (mi., km)
Rn Reynolds number (ρVℓ / μ)
S Wing area (ft.2, m2)
T Thrust (lb., N)
T Temperature (oF)
u Local x-direction velocity component
V Velocity, Speed (ft./sec., m/s, mph, km/h)
v Local y-direction velocity component
w Downwash velocity (ft./sec., m/s)
ż Sink rate (vertical velocity) (ft./sec., m/s)
Greek:
α Angle of attack (deg.)
Γ Circulation
γ Climb or glide angle (deg., rad.)
γ Ratio of specific heats in a fluid
ε Wing twist angle (deg.)
θ Downwash angle (deg.)
φ Velocity potential
Λ Wing sweep angle (deg.)
μ Dynamic viscosity
ν Kinematic viscosity (μ/ρ)
ρ Fluid mass density (kg/m3)

3. Presentation Overview
Case Studies
II. “Very large” transport airplanes (A380s, flying wings and C-wings)

4. Case II. The “Big Airplane” Problem
Antonov An 225 “Mriya”
Wing Span: 290 ft. (88.4 m)
MTOW: 1,322,750 lb. (600,000 kg)
Six 51,590 lb. ST (23,400 kgp)
Lotarev D-18T turbofans

5. Boeing Product Development Opportunities
(circa 1990)
In Production
Development or Study

6. Typical Marketing “Range-Payload” Diagram
(Market Niches –Product Development Opportunities – circa )
NLA
777
Seats
7J7
Range (nmi.)

7. Air Traffic Growth and Aircraft Arrival/Departure Data for Kennedy International Airport (to circa 1995)
Passengers
Per Year
(millions)
Aircraft
Per Year
(thousands)
Aircraft
Passengers 15 10 85 70 5
Advent of Wide-Body Transports
(B 747, DC-10, L 1011, etc.) 55 40
Year

8. Wake Vortex Separation Standards
Heavy (H) Airplanes over 300,00 lb. max. certified take-off weight (MCTOW)
(e.g. B777, B767, B747, MD 11)
Medium (M) Airplanes with MCTOW between 15,400 and 300,000 lbs.
Light (L) Airplanes with MCTOW less than 15,400 lbs.
Radar Separation: Time Separation:
Heavy behind Heavy 4 n. mi Medium behind Heavy min.
Medium behind Heavy 5 n. mi Light behind Heavy min.
Light behind A n. mi.
Light behind Heavy 6 n. mi.
Light behind Medium 5 n. mi.

9. “Square-Cube Law” Trends in Size & DOC
(Conventional “Tube and Wing” Configurations)
Direct Operating Cost
(cents/seat-mi.)
Wing Span (ft.)
~ 600
Passengers Passengers
Thanks to Ilan kroo

10. Classic Configuration Evolution
600+ passengers
~140 passengers
Super 747 (NLA)
Too long to fit in terminal gates, so..
7?7 (NLA)
Outboard engines at
wing tip stations of a 747
~ 425 passengers

11. Airbus A380 Jumbo Jumbo-Jet
Goodyear

12. Jumbo 600 Passenger Subsonic Transport (circa 1992)
Configuration Issues:
Runway limits
Taxiway limits
Terminal gate limits
Emergency
evacuation
Community noise
Wake vortices
Wing skin size
limits
Ditching/flotation
Passenger
comfort
Must fit within a 80 m box

13. Airbus A380 in a Cross Wind

14. Northrop B-49 bomber (circa 1948-49)
Northrop Grumman B-2

15. Early Attempts to Solve the “Large [600+ Passenger] Transport Airplane Problem”
McMasters/Boeing
Conceptual “747 XXL”
circa 1992
An Early Version of the Liebeck Blended Wing-Body Subsonic Transport
Wing Spans
b ≈ 300 ft.
Griffith airfoil
From the desk of J. H. McMasters, 1992

16. The Griffith Airfoil (circa 1944)
Favorable gradient for laminar flow -
Pressure recovery
(turbulent flow) CP ć c t
Conventional airfoil
(chord ć )
Suction slot +
Griffith airfoil
(chord c ) 1
Transonic Griffith airfoil

17. A Suite of Drag Reducing Wing Tip Devices

18. A Flawed (and Clumsy) Attempt to Emulate Nature

19. A Family of Non-Planar Wing Configurations Constant wing span (b), area (S) and height-to-span ratio [ h/b=0.2 ]
Total Drag (D) = Dviscous + Dinduced [+ Dcompressibility ] Dviscous ~ SwetV2f(CL)
Induced Drag (drag due to lift) = Di ~ kw [Lift (L)/span (b)]2x speed (V)-2 ~ kw [W/b] 2
kw = theoretical wing span efficiency factor = 1/ew In steady, level flight,
Lift (L) = Weight (W) b h
Biplane kw = 0.74
X-wing kw = 0.75
Branched tips kw = 0.76
(“pfeathers”)
Tip plates kw = 0.72
Box biplane kw = 0.68
Joined wing kw = 0.95
C-Wing kw = 0.69
Tip plated winglets kw = 0.83
Winglets kw = 0.71
Dihedral kw = 0.97
Note: For an optimally loaded planar wing of the same span and area kw = 1.0
Aspect ratio = b2 S
Treffetz plane analyses due to Prof. Ilan Kroo, Stanford University (circa 1992).

20. Non-Planar Wing Span Loads
Winglets
L/2 L1 L1
L/2 + L2
C-Wing L1
L/2 L2 L1 L2 h
b/2
b/2 h
Winglet-let

21. A Possible [Slightly Grotesque] C-Wing Large Transport Airplane Configuration
Baseline
Baseline Configuration
From the desk of J.H. McMasters, 1994

22. 600+ Passenger C-Wing Transport Configuration (Semi-Span Loader, Quasi-Three-Surface Airplanes)
Boeing configuration patent granted 1996.
McMasters, J.H. and Kroo, I. M., “Advanced Configurations for Very Large Subsonic Transport Airplanes”, NASA CR ,
Oct. 1996; also Aircraft Design, Vol. 1, No. 4, 1998, pp

23. Layout of Passenger Accommodations (LOPA) for a Single Deck, 3-Class, 600 Passenger C-Wing Transport

24. Size Comparison for a Conventional and C-Wing 600 Passenger Transport Airplane

25. Some Configuration Options For Very Large Commercial Transport Airplanes
“Transonic Seagull”
“Winged Watermelon”
(“Flying Spud”)
“Klingon Battle Cruiser”
Figure 25. Some Biomechanics Inspired Options for Very Large Airplanes.
2 or more “small” airplanes In formation ?
A “Smart” C-Wing BWB ?

26. Smart Wings Analogies Potential Benefits Pterosaur Airplane
Brain Computer
Nerves Fiber optic strain
gages, pressure
sensors
Bone and tissue Composite materials
Variable geometry Electro-mechanical
control via large control of large
and small muscles and small aerodynamic
devices distributed over
wing trailing edge
Potential Benefits
Reduced wing weight for a given wing
span
Increased span (reduced drag) for wing of
given weight
May enable the use of highly non-planar
wing configurations (e.g. C-wings)
Inputs from nerves
distributed throughout the living tissue of the wing membrane
Control output to muscles
throughout wing membrane
Ultra light weight structure (strong but highly flexible)
Kroo MITEs
(digitized, segmented
Gurney flaps)
Brain highly modified to process sensory data and provide needed control output