Cover
Preface
Acknowledgments
Abbreviations and Acronyms
About the Companion Website
1 Aircraft Engines – A Review
1. 1.1 Introduction
2. 1.2 Aerothermodynamics of Working Fluid
3. 1.3 Thrust and Specific Fuel Consumption
4. 1.4 Thermal and Propulsive Efficiency
5. 1.5 Gas Generator
6. 1.6 Engine Components
7. 1.7 Performance Evaluation of a Turbojet Engine
8. 1.8 Turbojet Engine with an Afterburner
9. 1.9 Turbofan Engine
10. 1.10 Turboprop Engine
11. 1.11 High‐Speed Air‐Breathing Engines
12. 1.12 Rocket‐Based Airbreathing Propulsion
13. 1.13 Summary
14. References
2 Aircraft Aerodynamics – A Review
1. 2.1 Introduction
2. 2.2 Similarity Parameters in Compressible Flow: Flight vs. Wind Tunnel
3. 2.3 Physical Boundary Conditions on a Solid Wall (in Continuum Mechanics)
4. 2.4 Profile and Parasite Drag
5. 2.5 Drag Due to Lift
6. 2.6 Waves in Supersonic Flow
7. 2.7 Compressibility Effects and Critical Mach Number
8. 2.8 Drag Divergence Phenomenon and Supercritical Airfoil
9. 2.9 Wing Sweep
10. 2.10 Delta Wing Aerodynamics
11. 2.11 Area‐Rule in Transonic Aircraft
12. 2.12 Optimum Shape for Slender Body of Revolution of Length ℓ in Supersonic Flow
13. 2.13 High‐Lift Devices: Multi‐Element Airfoils
14. 2.14 Powered Lift and STOL Aircraft
15. 2.15 Laminar Flow Control, LFC
16. 2.16 Aerodynamic Figures of Merit
17. 2.17 Advanced Aircraft Designs and Technologies for Leaner, Greener Aviation
18. 2.18 Summary
19. References
3 Understanding Aviation’s Impact on the Environment
1. 3.1 Introduction
2. 3.2 Combustion Emissions
3. 3.3 Engine Emission Standards
4. 3.4 Low‐Emission Combustors
5. 3.5 Aviation Fuels
6. 3.6 Interim Summary on Combustion Emission Impact on the Environment
7. 3.7 Aviation Impact on Carbon Dioxide Emission: Quantified
8. 3.8 Noise
9. 3.9 Engine Noise Directivity Pattern
10. 3.10 Noise Reduction at the Source
11. 3.11 Sonic Boom
12. 3.12 Aircraft Noise Certification
13. 3.13 NASA's Vision: Quiet Green Transport Technology
14. 3.14 FAA's Vision: NextGen Technology
15. 3.15 The European Vision for Sustainable Aviation
16. 3.16 Summary
17. References
4 Future Fuels and Energy Sources in Sustainable Aviation
1. 4.1 Introduction
2. 4.2 Alternative Jet Fuels (AJFs)
3. 4.3 Liquefied Natural Gas, LNG
4. 4.4 Hydrogen
5. 4.5 Battery Systems
6. 4.6 Fuel Cell
7. 4.7 Fuels for the Compact Fusion Reactor (CFR)
8. 4.8 Summary
9. References
5 Promising Technologies in Propulsion and Power
1. 5.1 Introduction
2. 5.2 Gas Turbine Engine
3. 5.3 Distributed Combustion Concepts in Advanced Gas Turbine Engine Core
4. 5.4 Multifuel (Cryogenic‐Kerosene), Hybrid Propulsion Concept
5. 5.5 Intercooled and Recuperated Turbofan Engines
6. 5.6 Active Core Concepts
7. 5.7 Topping Cycle: Wave Rotor Combustion
8. 5.8 Pulse Detonation Engine (PDE)
9. 5.9 Humphrey Cycle vs. Brayton: Thermodynamics
10. 5.10 Boundary‐Layer Ingestion (BLI) and Distributed Propulsion (DP) Concept
11. 5.11 Distributed Propulsion Concept in Early Aviation
12. 5.12 Distributed Propulsion in Modern Aviation
13. 5.13 Interim Summary on Electric Propulsion (EP)
14. 5.14 Synergetic Air‐Breathing Rocket Engine; SABRE
15. 5.15 Compact Fusion Reactor: The Path to Clean, Unlimited Energy
16. 5.16 Aircraft Configurations Using Advanced Propulsion Systems
17. 5.17 Summary
18. References
6 Pathways to Sustainable Aviation
1. 6.1 Introduction
2. 6.2 Pathways to Certification
3. 6.3 Energy Pathways in Sustainable Aviation
4. 6.4 Future of GT Engines
5. 6.5 Summary
6. References
Index
End User License Agreement

List of Tables

Chapter 1
1. Table 1.1 The parameters in a gas generator.
2. Table 1.2 New parameters in afterburner.
3. Table 1.3 Summary of ramjet equations in terms of dimensional parameters (for...
4. Table 1.4 Summary of ramjet equations in terms of nondimensional parameters (...
Chapter 2
1. Table 2.1 Numerical solution of the Blasius equation for incompressible lamin...
2. Table 2.2 Summary of laminar boundary‐layer characteristic parameters on a fl...
3. Table 2.3 Summary of compressible laminar boundary‐layer parameters on an adi...
4. Table 2.4 Summary of Stanton number correlations in compressible boundary lay...
5. Table 2.5 Summary of finite wing aerodynamic parameters of elliptic and gener...
6. Table 2.6 Impact of wing aspect ratio on lift curve slope for unswept wings.
Chapter 3
1. Table 3.1 EPA and ICAO Engine Emission Standards in LTO cycle.
2. Table 3.2 Engine emissions with staged combustors.
3. Table 3.3 Comparison between the subsonic engine of 1992 and the design goals...
4. Table 3.4 Performance and operational requirements of a modern aircraft engin...
5. Table 3.5 Some fuel properties of interest to aviation.
6. Table 3.6 Hydrogen content (based on mass) and lower heating value of common ...
7. Table 3.7 Important jet fuel properties.
8. Table 3.8 Modern aeroengines and their NO_x emission.
9. Table 3.9 Carbon dioxide production by various hydrocarbon fuels.
10. Table 3.10 Fuel burn data for B737‐400.
11. Table 3.11 Estimated CO₂ Emission for B737‐400.
12. Table 3.12 Health and environmental effects of air pollutants.
13. Table 3.13 National ambient air quality standards.
14. Table 3.14 Fan design parameters (Allison).
15. Table 3.15 Chevron noise benefit and cruise thrust loss data.
16. Table 3.16 Preliminary performance data.
17. Table 3.17 NASA subsonic transport system level metrics.
18. Table 3.18 NASA's environmental goals for supersonic aircraft (see Huff 2013)...
19. Table 3.19 NASA's performance goals for supersonic aircraft (see Huff 2013).
20. Table 3.20 Emission goals in EU'sFlightpath 2050.
Chapter 4
1. Table 4.1 The range of GHG emissions for CNG and biomethane (road vehicles).
2. Table 4.2 Properties of methanol and ethanol and comparison to kerosene.
3. Table 4.3 The range ofWTT (well‐to‐tank), TTWs (tank‐to‐wheels...
4. Table 4.4 Technology readiness level for alternative jet fuel (AJF).
5. Table 4.5 Biofuels and pathways to certification (as of 2015).
6. Table 4.6 Biofuel yield from feedstock.
7. Table 4.7 Land use needed for (global 2030) biofuel production from feedstock...
8. Table 4.8 Land use requirement for (50/50 blend) biofuel production (global 2...
9. Table 4.9 Land use requirement for biocrop conversion to electricity.
10. Table 4.10 Properties of LNG and methane.
11. Table 4.11 Gravimetric (GED) andvolumetric energy density (VED) and cost of l...
12. Table 4.12 Forecast of battery energy density in 10–20 yr.
13. Table 4.13 Cooling requirements for lithium‐ion batteries.
14. Table 4.14 Example of recharging a 1500 kWh battery in flight.
15. Table 4.15 Example of electric‐assist in takeoff and climb
16. Table 4.16 Operational characteristics of fuel cells
Chapter 5
1. Table 5.1 Common parameters in the two UHB turbofan architecture.
2. Table 5.2 Parameters unique to the two UHB engines.
3. Table 5.3 Performance gains in two‐burner UHB at takeoff.
4. Table 5.4 Impact of multifuel engine architecture on performance parameters.
5. Table 5.5 Climate impact (%).
6. Table 5.6 APU cycle parameters.
7. Table 5.7 APU performance results.
8. Table 5.8 Probability of engine(s) failure on aircraft with multiple engines.
9. Table 5.9 NASA STARC ABL electrical component assumptions (non‐superconductin...
10. Table 5.10 Key performance parameters in electric aircraft and electric car.
11. Table 5.11 Key performance parameters for power electronics in electric aircr...
12. Table 5.12 Battery vs jet fuel.
13. Table 5.13 N3‐X design point.
14. Table 5.14 N3‐X mission parameters.
15. Table 5.15 N3‐X SC technology and design parameters and definitions.
16. Table 5.16 N3‐X performance relative to baseline^a aircraft.
17. Table 5.17 Electrical system efficiencies for N3‐X/MgB₂/LH₂.
18. Table 5.18 Comparison of the Cirrus SR22 with the LEAPTech aircraft.

List of Illustrations

Chapter 1
1. Figure 1.1 Temperature dependence of specific heats for a diatomic gas.
2. Figure 1.2 Station numbers for a turbojet with afterburner (TJ‐AB) engine.
3. Figure 1.3 Schematic drawing of an air‐breathing engine with a box‐like cont...
4. Figure 1.4 Schematic drawing of a turbofan engine with separate exhausts: (a...
5. Figure 1.5 Flow detail near a blunt cowl lip showing lip thrust component an...
6. Figure 1.6 Definition of installed net thrust in terms of internal and exter...
7. Figure 1.7 Thermal power input (by fuel) and the mechanical power production...
8. Figure 1.8 Schematic drawing of a power turbine placed in the exhaust of a g...
9. Figure 1.9 Schematic drawing of a gas turbine engine with a regenerative sch...
10. Figure 1.10 T‐s diagram of a Carnot cycle.
11. Figure 1.11 Schematic drawing of an aircraft engine installation showing the...
12. Figure 1.12 Aircraft in unaccelerated level flight showing a balance between...
13. Figure 1.13 Schematic drawing of a gas generator.
14. Figure 1.14 Enthalpy‐entropy (h‐s) diagram of an aircraft engine inlet flow ...
15. Figure 1.15 Schematic drawing of a subsonic nozzle with its static pressure ...
16. Figure 1.16 A choked C‐D nozzle and the static pressure distribution along t...
17. Figure 1.17 Enthalpy‐entropy (h‐s) diagram of nozzle flow expansion.
18. Figure 1.18 Two figures of merit in a nozzle plotted as a function of NPR (γ...
19. Figure 1.19 Enthalpy‐entropy (h‐s) diagram for the three possible nozzle exp...
20. Figure 1.20 Enthalpy‐entropy (h‐s) diagram of an actual and ideal compressio...
21. Figure 1.21 Variation of compressor adiabatic efficiency with the pressure r...
22. Figure 1.22 Components of a conventional combustion chamber and the first tu...
23. Figure 1.23 Block diagram of a burner with mass and energy balance: (a) mass...
24. Figure 1.24 Actual flow process in a burner (note total pressure loss, Δp_t, ...
25. Figure 1.25 Common shaft in a gas generator connects the compressor and turb...
26. Figure 1.26 Expansion process in an uncooled turbine (note the entropy rise ...
27. Figure 1.27 Variation of turbine adiabatic efficiency,η_t, with the inve...
28. Figure 1.28 Two‐spool GT engine with two stations of compressor bleed for co...
29. Figure 1.29 Enthalpy‐entropy (h‐s) diagram for a turbine with two cooled sta...
30. Figure 1.30 h‐s diagram of the coolant stream, first inside the blade, then ...
31. Figure 1.31 T‐s diagram of a turbojet engine with component losses and Imper...
32. Figure 1.32 Schematic drawing of an afterburning turbojet engine.
33. Figure 1.33 Schematic drawing of an afterburner with its station numbers.
34. Figure 1.34 Nondimensional T‐s diagram for an ideal afterburning turbojet en...
35. Figure 1.35 Schematic drawing of a separate‐exhaust turbofan engine with two...
36. Figure 1.36 Schematic of a long‐duct turbofan engine with a mixer.
37. Figure 1.37 Enthalpy‐entropy (h‐s) diagram representing the flow process in ...
38. Figure 1.38 Definition sketch for various mass flow rates in a separate‐exha...
39. Figure 1.39 Turbine expansion possibilities, including the impossible range....
40. Figure 1.40 Variation of turbine power parameter (1 − τ_t) with the fan ...
41. Figure 1.41 T‐s diagram of a compression (fan) inlet stream followed by the ...
42. Figure 1.42 The effect of bypass ratio on TF‐efficiency and fuel burn.
43. Figure 1.43 The effect of bypass ratio on thermodynamics of a turbofan cycle...
44. Figure 1.44 Schematic drawing of the low‐pressure spool in a UHB with fan dr...
45. Figure 1.45 Long‐duct turbofan engine with a mixer and an afterburner.
46. Figure 1.46 Mixer control volume showing nonuniform inlet and mixed‐out...
47. Figure 1.47 Mixing of two streams at different temperatures on a T‐s diagram...
48. Figure 1.48 Performance characteristics of a mixed TF engine with AB in crui...
49. Figure 1.49 Schematic drawing of a turboprop engine with station numbers ide...
50. Figure 1.50 Thermodynamic states of an expansion process in free turbine and...
51. Figure 1.51 Definition of power split, α, in a turboprop engine.
52. Figure 1.52 Performance of a TP engine in cruise with variable power split, ...
53. Figure 1.53 Unducted‐Fan (UDF) counter‐rotating model at NASA‐Lewis (now Gle...
54. Figure 1.54 Approximate variation of specific impulse with flight Mach numbe...
55. Figure 1.55 Flow parameter trends in a typical subsonic‐combustion ramjet.
56. Figure 1.56 Conventional (subsonic‐combustion) ramjet cycle and its ideal th...
57. Figure 1.57 Typical arrangement of a generic scramjet engine on a hypersonic...
58. Figure 1.58 Static and stagnation states of gas in a scramjet engine.
59. Figure 1.59 A frictionless, constant‐pressure combustor.
60. Figure 1.60 Schematic drawing of a gas generator ram‐rocket.
61. Figure 1.61 Ram‐rocket configuration.
62. Figure 1.62 Concept in rocket‐based‐combined‐cycle (RBCC) propulsion.
Chapter 2
1. Figure 2.1 Aircraft drag tree.
2. Figure 2.2 European Transonic Windtunnel (ETW) Mach‐Reynolds number envelope...
3. Figure 2.3 The wall shear stress in a viscous fluid causes friction drag on ...
4. Figure 2.4 Temperature distribution in a viscous fluid (in the y‐direction)....
5. Figure 2.5 Thermal boundary conditions on a (solid) wall: (a) heated wall (T
6. Figure 2.6 Flat plate of length c, at zero incidence, in viscous fluid flow....
7. Figure 2.7 Laminar boundary‐layer velocity profile on a flat plate based on ...
8. Figure 2.8 Friction drag coefficient in compressible boundary layer With adi...
9. Figure 2.9 Coefficient of viscosity of dry air, μ(T), in kg/ms, at p = ...
10. Figure 2.10 Specific heat at constant pressure, c_p in kJ/kgK, at p = 1 atm. ...
11. Figure 2.11 Thermal conductivity, k, of dry air in W/mK, at p = 1 atm.
12. Figure 2.12 Prandtl number of dry air at p = 1 atm.
13. Figure 2.13 Process of natural transition from laminar to turbulent boundary...
14. Figure 2.14 Velocity and mean shear profiles in laminar and turbulent bounda...
15. Figure 2.15 Distribution of shape factor, H₁₂, on a flat plate and on an air...
16. Figure 2.16 Definition sketch of a plain airfoil.
17. Figure 2.17 Airfoil trailing edge shapes and boundary conditions: (a) finite...
18. Figure 2.18 Definition sketch of forces and moments on an airfoil in angle o...
19. Figure 2.19 Graphical depiction of zero‐lift line and α_L=0.
20. Figure 2.20 Pre‐ and post‐stall behavior of lift coefficient with angle of a...
21. Figure 2.21 Positive and negative stall characteristics of a thin airfoil in...
22. Figure 2.22 Pitching moment coefficient at quarter‐chord for a thin airfoil ...
23. Figure 2.23 Effect of chord Reynolds number on lift coefficient in high‐Reyn...
24. Figure 2.24 Effect of leading‐edge devices (LED) such as slats, leading‐edge...
25. Figure 2.25 Behavior of lift coefficient of a thin airfoil with trailing‐edg...
26. Figure 2.26 Friction drag coefficient on (one side of) a flat plate in the i...
27. Figure 2.27 Drag polar of four NACA 64‐series airfoil sections of various th...
28. Figure 2.28 The effect of pressure gradient on velocity profile in a laminar...
29. Figure 2.29 Finite wing with its trailing wake (shown for half‐span) in unif...
30. Figure 2.30 Geometric parameters of a finite wing of trapezoidal planform wi...
31. Figure 2.31 Definition sketch of four angles on a cambered airfoil on a fini...
32. Figure 2.32 Lifting characteristic of straight wings of finite or infinite A...
33. Figure 2.33 Experimental aircraft with bell spanload design in flight.
34. Figure 2.34 Induced flow along the wing span (a), and vortex rollup (b).
35. Figure 2.35 Acoustic wave propagation in sonic and supersonic flows (or the ...
36. Figure 2.36 Wave front created by a small disturbance moving at a supersonic...
37. Figure 2.37 Sketch of oblique waves: four oblique shock (OS) waves and two c...
38. Figure 2.38 Definition sketch of velocity components normal and parallel to ...
39. Figure 2.39 (a) Plane oblique shock chart for γ = 1.4.; (b) Plane obliq...
40. Figure 2.40 Incremental turning across a Mach wave with velocity resolved in...
41. Figure 2.41 Sketch of a Mach wave and its right triangle.
42. Figure 2.42 Prandtl‐Meyer function and Mach angle (in degrees) for a diatomi...
43. Figure 2.43 Compressibility correction applied to an airfoil pressure coeffi...
44. Figure 2.44 Graphical construction of critical Mach number on an airfoil at ...
45. Figure 2.45 Family of Karman‐Tsien (K‐T) compressibility correction factors ...
46. Figure 2.47 Corrected pressure distribution data on SC(2)‐0714 at high lift ...
47. Figure 2.46 The 14% thick, NASA SC(2)‐0714 airfoil shape. (SC(2) designation...
48. Figure 2.48 The behavior of profile drag for NACA 2315 airfoil with AoA and ...
49. Figure 2.49 Increase in critical Mach number for a swept wing with constant ...
50. Figure 2.50 Aerodynamic behavior of variable‐sweep aircraft: (a) impact of v...
51. Figure 2.51 Four delta‐wing planforms: (a) simple delta wing; (b) cropped de...
52. Figure 2.52 Three‐views of a delta wing with its leading‐edge vortex formati...
53. Figure 2.53 Variation of K_P and K_V for delta wings at M ≅ 0.
54. Figure 2.54 Lift curve slope of a delta wing and the details of LE‐vortex se...
55. Figure 2.55 Trends of lift and lift‐to‐drag variation on a flat delta wing w...
56. Figure 2.56 Dye injection in the vortex core of a delta wing in water tunnel...
57. Figure 2.57 Colored dye flow visualization in a water tunnel on a 1/48th sca...
58. Figure 2.58 Application of transonic area‐rule to three wing−body combinatio...
59. Figure 2.59 Supersonic fighter, F‐102, that flew supersonically only after a...
60. Figure 2.60 A pointed slender axisymmetric body of length, l, in supersonic ...
61. Figure 2.61 The shape of Sears‐Haack body and its cross‐sectional area distr...
62. Figure 2.62 Von Karman Ogive with base area, S(l).
63. Figure 2.63 Von Karman ogive for ℓ = 1.0 and a base area, S(ℓ) = 0.1.
64. Figure 2.64 Typical LE and TE devices on aircraft wing sections. (a) airfoil...
65. Figure 2.65 Effect of some high‐lift devices on C_{l, max}.
66. Figure 2.66 The effect of high‐lift devices on aircraft C_L vs. AoA in approa...
67. Figure 2.67 Interaction of the trailing‐edge flap system with the jet in lan...
68. Figure 2.68 The effect of wing sweep angle on C_L,max of wings of moderate as...
69. Figure 2.69 NASA Extreme Short Takeoff and Landing (ESTOL) aircraft concept ...
70. Figure 2.70 Laminar flow control concepts. : (a) NLF, LFC, HLFC concepts for...
71. Figure 2.71 Benefits of HLFC on advanced supersonic transport at Mach 2.4, 6...
72. Figure 2.72 Boeing 737‐800 ecoDemonstrator with laminar flow winglet for 737...
73. Figure 2.73 The first production aircraft with HLFC.
74. Figure 2.74 NASA 40′ × 80′ tunnel with tufts on Boeing 757 fin and rudder....
75. Figure 2.75 Conceptual blended wing−body design for low‐noise and high‐cruis...
76. Figure 2.76 Aircraft drag polar with graphical construction of (L/D)_max.
77. Figure 2.77 Drag polars of subsonic and supersonic aircraft: (a) subsonic ai...
78. Figure 2.78 The drag polar of a diamond airfoil in AoA.
79. Figure 2.79 Lift‐drag ratio of a 10% thick diamond airfoil in Mach flow as...
80. Figure 2.80 Typical C_L vs. angle of attack for a conventional aircraft.
81. Figure 2.81 Supersonic drag buildup.
82. Figure 2.82 Blended wing−body aircraft for reduced noise and higher cruise e...
83. Figure 2.83 Northrop Grumman's concept aircraft designed for commercial avia...
84. Figure 2.84 Box wing airliner concept plane for reduced drag.
85. Figure 2.85 Wide fuselage for enhanced lift, boundary‐layer ingestion (BLI) ...
86. Figure 2.86 The Volt is a hybrid gas turbine and battery technology plane de...
87. Figure 2.87 Hybrid wing body, H series, future aircraft concept from MIT....
88. Figure 2.88 X‐59A Low Boom X‐Plane: Greener‐Quieter‐Safer.
Chapter 3
1. Figure 3.1 Tank‐to‐wake products of combustion of fossil fuel in...
2. Figure 3.2 September ice sheet extent and age in the arctic in 1984 and 2016...
3. Figure 3.3 Concentration of carbon dioxide in the atmosphere since 1000 base...
4. Figure 3.4 Recent monthly mean carbon dioxide measured at Mauna Loa Observat...
5. Figure 3.5 The inventory of GHG emissions in the United States in 2014.
6. Figure 3.6 Sources of CO₂ emissions in the United States in 2014.
7. Figure 3.7 Coal power plants in the continental US.
8. Figure 3.8 Emission index of carbon monoxide and unburned hydrocarbons (labe...
9. Figure 3.9 Correlation of current engine NO_x emissions with combustor inlet ...
10. Figure 3.10 Impact of cycle pressure ratio (PR) and flight Mach number on NO
11. Figure 3.11 Profile of ozone concentration with altitude with a suitable cru...
12. Figure 3.12 Emission characteristics of fan engine versus load at sea level ...
13. Figure 3.13 Water injection in the combustor reduces NO_x emission.
14. Figure 3.14 Effect of residence time (in ms) and φ on NO_x emission leve...
15. Figure 3.15 Approaches to a low‐NO_x combustor development.
16. Figure 3.16 Skin temperature rise with flight Mach number (γ = 1.4, T_amb ≅ −...
17. Figure 3.17 Distillation curve for common jet fuels – a measure of fuel vola...
18. Figure 3.18 Thermal stability limit and relative price of aviation fuels (re...
19. Figure 3.19 Ignition temperatures for petroleum fuels.
20. Figure 3.21 History of ICAO NO_x regulations for jet engines (with thrust > 3...
21. Figure 3.20 Petroleum products extracted from crude oil (in percent volume)....
22. Figure 3.22 Fuel burn and CO₂ emissions in a short‐haul commercial transport...
23. Figure 3.23 CO_2e emissions per seat as a function of flight distance.
24. Figure 3.24 Center frequencies in octave band and one‐third octave band filt...
25. Figure 3.25 Typical flyover noise spectrum using one‐third octave band filte...
26. Figure 3.26 A‐weighting corrections in dB for octave and one‐third octave ba...
27. Figure 3.27 Spherical (sound) wave propagation in a medium at rest.
28. Figure 3.28 The flow pattern associated with a dipole and a vibrating blade:...
29. Figure 3.29 Two dipoles of equal strength are placed at a distance d apart t...
30. Figure 3.30 Instantaneous fluctuating pressure field due to vortex shedding ...
31. Figure 3.31 Adaptive compliant trailing edge technology. https://www.flxsys....
32. Figure 3.32 Gulfstream III is modified to test the ACTE flexible‐flap resear...
33. Figure 3.33 Noise sources in a separate‐flow turbofan engine.
34. Figure 3.34 The effect of fan tip relative Mach number on spectral content o...
35. Figure 3.35 Concepts in fan noise reduction: (a) partially assembled fan sta...
36. Figure 3.36 Fan noise reduction research.
37. Figure 3.37 The formation of large‐scale vortical structures in a subsonic f...
38. Figure 3.38 Narrow‐band supersonic jet noise spectrum in farfield.
39. Figure 3.39 Acoustic power dependency on jet speed.
40. Figure 3.40 Directivity of the radiated sound from an aircraft engine (JT‐15...
41. Figure 3.41 Directional distribution of radiated sound (relative to peak) fr...
42. Figure 3.42 Noise directivity pattern and the SPL in dB for a turbulent (rou...
43. Figure 3.43 Measured noise directivities at selected Strouhal numbers in a M...
44. Figure 3.44 Impact of wing shielding on aircraft noise mitigation: (a) confi...
45. Figure 3.45 Noise‐reduction technologies.
46. Figure 3.46 New low‐drag acoustic liner with slotted face sheet undergoing f...
47. Figure 3.47 Baseline nozzle (3BB) and examples of chevron and tab configurat...
48. Figure 3.48 Sonic boom overpressure and signature on the ground (an idealize...
49. Figure 3.49 Supersonic fighter, F‐4C and its sonic boom pressure time histor...
50. Figure 3.50 The reduction in sonic boom levels, in ground overpressure, with...
51. Figure 3.51 NASA X‐59 QueSST aircraft designed for low‐boom commercial super...
52. Figure 3.52 NASA's low‐boom supersonic test case.
53. Figure 3.53 55‐seat supersonic airliner under development at Boom Supersonic...
54. Figure 3.54 AS2 supersonic business jet designed by Aerion Corporation for M...
55. Figure 3.55 FAA Stage‐4 aircraft certification guidelines for turbofan power...
56. Figure 3.56 Approach and departure trajectories, and the location of referen...
57. Figure 3.57 Advancements in aircraft noise from 1960 to 2020: (a) historic t...
58. Figure 3.58 Noise components of an aircraft with turbofan engine during take...
Chapter 4
1. Figure 4.1 Schematic drawing of hybrid electric propulsion systems: (a) para...
2. Figure 4.2 Hybrid electric propulsion on a conventional (tube and wing) conf...
3. Figure 4.3 N3‐X Turboelectric distributed propulsion (TeDP) system wit...
4. Figure 4.4 Forecast on alternative jet fuels adoption in civil aviation.
5. Figure 4.5 Test flights (2008–2013) using sustainable jet fuels.
6. Figure 4.6 Airbus A320 Advanced Technology Research Aircraft (ATRA) before f...
7. Figure 4.7 Supersonic fighter aircraft, Gripen, undergoing flight test on 10...
8. Figure 4.8 NASA DC‐8 contrail and emissions flight test using JP‐8 and renew...
9. Figure 4.9 Comparison of carbon‐dioxide production in the manufacture and us...
10. Figure 4.10 Schematic of converting biodiesel (HRD) to jet fuel (HRJ) throug...
11. Figure 4.11 Availability of marginal lands with renewable energy potential i...
12. Figure 4.12 Renewable energy potential on marginal lands in the United State...
13. Figure 4.13 Strong miscanthus yield (in tons/acre) map in the continental Un...
14. Figure 4.14 Biofuel plants and their capacity in the continental United Stat...
15. Figure 4.15 Lifecycle GHG emissions for drop‐in (bio) jet fuels compared to ...
16. Figure 4.16 Percent reduction of lifecycle GHG emissions of bio‐jet fuels co...
17. Figure 4.17 Relative volume of natural gas at atmospheric temperate and pres...
18. Figure 4.18 Statistics of the US energy use, 1998–2004.
19. Figure 4.19 Typical composition of natural gas.
20. Figure 4.20 Typical composition of LNG.
21. Figure 4.21 Flammability range for methane/LNG (mixture with air).
22. Figure 4.22 Batteries and the electric power production and distribution sys...
23. Figure 4.23 Energy density, in Wh/kg, for different batteries.
24. Figure 4.24 Lithium‐air open‐cycle battery anticipated to reach 2000 Wh kg⁻¹...
25. Figure 4.25 Voltair configuration.
26. Figure 4.26 Schematic drawing of a fuel cell using hydrogen fuel.
27. Figure 4.27 DT reaction of atomic nuclei of deuterium‐tritium, in a fusion r...
Chapter 5
1. Figure 5.1 Worldwide fuel burn by aircraft type.
2. Figure 5.2 Core thermal, propulsive and overall efficiencies of commercial a...
3. Figure 5.3 Schematic drawing of a geared ultra‐high bypass ratio turbofan en...
4. Figure 5.4 Counter‐rotating open‐rotor (CROR) engine architecture with bypas...
5. Figure 5.5 An alternative GT architecture to the conventional gas turbine de...
6. Figure 5.6 Thermodynamics of a UHB‐TF gas turbine engine cycle with a single...
7. Figure 5.7 Material, gas or turbine entry temperature up to year 2030.
8. Figure 5.8 Turbine cooling methods and relative cooling flow requirement....
9. Figure 5.9 The schematic of the multifuel hybrid engine concept. (a) Separat...
10. Figure 5.10 T‐s diagram of the multifuel hybrid gas turbine engine that uses...
11. Figure 5.11 A Multifuel (cryogenic/kerosene) BWB aircraft concept.
12. Figure 5.12 Thermal efficiency of different gas turbine cycles.
13. Figure 5.13 Flowpath in an intercooled turbofan engine.
14. Figure 5.14 Intercooled recuperated turbofan engine concept by MTU Aero Engi...
15. Figure 5.15 A cryo‐intercooler concept with recuperative cycle.
16. Figure 5.16 Schematic drawing of a UHB showing the relative proportion of fa...
17. Figure 5.17 Active core concepts.(a) Closed‐loop active clearance and su...
18. Figure 5.18 Impact of component efficiency improvements and −100 K reduced t...
19. Figure 5.19 The rotating drum in a wave rotor combustion system and the test...
20. Figure 5.20 Wave rotor/gas turbine engine integration variants (HPT is high‐...
21. Figure 5.21 Schematics drawing of a wave‐rotor topped turboshaft engine.
22. Figure 5.22 Off‐design (i.e. 85% power) performance benefit of a wave rotor ...
23. Figure 5.23 Schematic diagram of a wave rotor burner system with its four‐po...
24. Figure 5.24 Design‐point wave rotor pressure ratio variation with temperatur...
25. Figure 5.25 Schematics of baseline and wave rotor‐topped turbofan engines....
26. Figure 5.26 Impact of wave rotor topped turbofan engine on aircraft TOGW for...
27. Figure 5.27 Schematic drawings of baseline and two wave rotor‐enhanced APUs....
28. Figure 5.28 Constant‐volume and constant‐pressure combustion cycles in p‐v a...
29. Figure 5.29 Thermal efficiency of ideal Humphrey (for γ = 1.4) and Brayton c...
30. Figure 5.30 The wave system in an idealized PDE thrust tube, in the laborato...
31. Figure 5.31 The pulse detonation engine with a trigger chamber.
32. Figure 5.32 Specific impulse, I_sp, in seconds, of a pressure‐gain combustor ...
33. Figure 5.33 The first PDE‐powered aircraft; the Long E‐Z, flew on January 31...
34. Figure 5.34 Schematic drawing of the components in a pulse detonation rocket...
35. Figure 5.35 Comparison of aircraft area distribution.
36. Figure 5.36 Thrust‐specific fuel consumption for PDE and TRJ along baseline ...
37. Figure 5.37 The PDE‐based spaceplane developed for space tourism.
38. Figure 5.38 Comparison between an ideal jet‐wake structure in a conventional...
39. Figure 5.39 Double bubble, D8, advanced civil transport.
40. Figure 5.40 Küchemann's jet‐wing concept with distributed propulsion inside ...
41. Figure 5.41 Northrop YB‐49 uses eight wing‐embedded jet engines.
42. Figure 5.42 The impact of flow control on aircraft drag reduction and noise ...
43. Figure 5.43 Constant‐area transition duct geometry, flowfield, and design gu...
44. Figure 5.44 “Stall Margin” chart for the neutral (i.e. constant‐area) and ac...
45. Figure 5.45 Distributed propulsion with BLI in a BWB aircraft: (a) BWB aircr...
46. Figure 5.46 BWB subsonic transport aircraft with conventional Aft‐mounted pr...
47. Figure 5.47 Examples of the US bomber aircraft that used 6–10 engines: (a) C...
48. Figure 5.48 Six possibilities for two‐engines inoperative on a four‐engine a...
49. Figure 5.49 Target engine in‐flight shutdown rate per 1000 engine hours.
50. Figure 5.50 Schematic drawing of two hybrid‐electric propulsion system archi...
51. Figure 5.51 “Propulsive fuselage” hybrid‐electric concept by Bauhaus Luftfah...
52. Figure 5.52 Single‐aisle turboelectric aircraft with aft‐boundary‐layer inge...
53. Figure 5.53 Schematic drawing of a turboelectric propulsion system driving a...
54. Figure 5.54 Schematic drawing of partial turboelectric propulsion system dri...
55. Figure 5.55 Schematic drawing of an all‐electric propulsion system (here sho...
56. Figure 5.56 The timeline of superconducting materials and some cryogenic liq...
57. Figure 5.57 Schematic drawing of a GT‐based‐TF engine and an electric fan dr...
58. Figure 5.58 The change in ideal jet Mach number and fan jet noise (expressed...
59. Figure 5.59 HTS motor driving an electric fan: (a) electric fan‐electric mot...
60. Figure 5.60 Fully superconducting electric motor/generator.
61. Figure 5.61 Zunum Aero hybrid‐electric regional aircraft (12 seater).
62. Figure 5.62 Airbus E‐Fan‐X flight demonstrator
63. Figure 5.63 Critical components in SABRE engine.
64. Figure 5.64 SABRE cycle showing its closed loop helium pre‐cooler and the en...
65. Figure 5.65 The aerospace plane “SKYLON.”
66. Figure 5.66 Schematic drawing of a turbojet engine with a nuclear reactor re...
67. Figure 5.67 Superconducting magnets in LM fusion research rig to confine pla...
68. Figure 5.68 Distributed turboelectric propulsion concept aircraft.
69. Figure 5.69 Turboelectric distributed propulsion concept.
70. Figure 5.70 Superconducting network and electric power management.
71. Figure 5.71 Distributed turbo‐electric propulsion.
72. Figure 5.72 Modified BAe 146 aircraft used as hybrid electric flight demonst...
73. Figure 5.73 NASA X‐57, an all‐electric distributed propulsion flight demonst...
74. Figure 5.74 Cirrus SR22 and LEAPTech; a comparison.
Chapter 6
1. Figure 6.1 Two examples of eVTOL aircraft chosen for the urban air mobility ...
2. Figure 6.2 Pathways to produce alternative drop‐in jet fuel (without oxygen)...
3. Figure 6.3 Market infusion pathway by electric propulsion.
4. Figure 6.4 E‐Fan X flight demonstrator is a modified BAe 146 aircraft showin...
5. Figure 6.5 Pathway to sustainable aviation in aircraft drag reduction and sy...
6. Figure 6.6 Projected time frame to achieve TRL 6 in hybrid electric propulsi...

Aerospace Series

Conceptual Aircraft Design: An Industrial Approach
Ajoy Kumar Kundu, Mark A. Price, David Riordan

Helicopter Flight Dynamics: Including a Treatment of Tiltrotor Aircraft, 3rd Edition
Gareth D. Padfield

Space Flight Dynamics, 2nd Edition
Craig A. Kluever

Performance of the Jet Transport Airplane: Analysis Methods, Flight Operations, and Regulations
Trevor M. Young

Small Unmanned Fixed‐Wing Aircraft Design: A Practical Approach
Andrew J. Keane, András Sóbester, James P. Scanlan

Advanced UAV Aerodynamics, Flight Stability and Control: Novel Concepts, Theory and Applications
Pascual Marqués, Andrea Da Ronch

Differential Game Theory with Applications to Missiles and Autonomous Systems Guidance
Farhan A. Faruqi

Introduction to Nonlinear Aeroelasticity
Grigorios Dimitriadis

Introduction to Aerospace Engineering with a Flight Test Perspective
Stephen Corda

Aircraft Control Allocation
Wayne Durham, Kenneth A. Bordignon, Roger Beck

Remotely Piloted Aircraft Systems: A Human Systems Integration Perspective
Nancy J. Cooke, Leah J. Rowe, Winston Bennett Jr., DeForest Q. Joralmon

Theory and Practice of Aircraft Performance
Ajoy Kumar Kundu, Mark A. Price, David Riordan

Adaptive Aeroservoelastic Control
Ashish Tewari

The Global Airline Industry, 2nd Edition
Peter Belobaba, Amedeo Odoni, Cynthia Barnhart

Modeling the Effect of Damage in Composite Structures: Simplified Approaches
Christos Kassapoglou

Introduction to Aircraft Aeroelasticity and Loads, 2nd Edition
Jan R. Wright, Jonathan Edward Cooper

Theoretical and Computational Aerodynamics
Tapan K. Sengupta

Aircraft Aerodynamic Design: Geometry and Optimization
András Sóbester, Alexander I J Forrester

Stability and Control of Aircraft Systems: Introduction to Classical Feedback Control
Roy Langton

Aerospace Propulsion
T. W. Lee

Civil Avionics Systems, 2nd Edition
Ian Moir, Allan Seabridge, Malcolm Jukes

Aircraft Flight Dynamics and Control
Wayne Durham

Modelling and Managing Airport Performance
Konstantinos Zografos, Giovanni Andreatta, Amedeo Odoni

Advanced Aircraft Design: Conceptual Design, Analysis and Optimization of Subsonic Civil Airplanes
Egbert Torenbeek

Design and Analysis of Composite Structures: With Applications to Aerospace Structures, 2nd Edition
Christos Kassapoglou

Aircraft Systems Integration of Air‐Launched Weapons
Keith A. Rigby

Understanding Aerodynamics: Arguing from the Real Physics
Doug McLean

Design and Development of Aircraft Systems, 2nd Edition
Ian Moir, Allan Seabridge

Aircraft Design: A Systems Engineering Approach
Mohammad H. Sadraey

Introduction to UAV Systems, 4th Edition
Paul Fahlstrom, Thomas Gleason

Theory of Lift: Introductory Computational Aerodynamics in MATLAB/Octave
G. D. McBain

Sense and Avoid in UAS: Research and Applications
Plamen Angelov

Morphing Aerospace Vehicles and Structures
John Valasek

Spacecraft Systems Engineering, 4th Edition
Peter Fortescue, Graham Swinerd, John Stark

Unmanned Aircraft Systems: UAVS Design, Development and Deployment
Reg Austin

Gas Turbine Propulsion Systems
Bernie MacIsaac, Roy Langton

Aircraft Systems: Mechanical, Electrical, and Avionics Subsystems Integration, 3rd Edition
Ian Moir, Allan Seabridge

Basic Helicopter Aerodynamics, 3rd Edition
John M. Seddon, Simon Newman

System Health Management: with Aerospace Applications
Stephen B Johnson, Thomas Gormley, Seth Kessler, Charles Mott, Ann Patterson‐Hine, Karl Reichard, Philip Scandura Jr.

Advanced Control of Aircraft, Spacecraft and Rockets
Ashish Tewari

Air Travel and Health: A Systems Perspective
Allan Seabridge, Shirley Morgan

Principles of Flight for Pilots
Peter J. Swatton

Handbook of Space Technology
Wilfried Ley, Klaus Wittmann, Willi Hallmann

Cooperative Path Planning of Unmanned Aerial Vehicles
Antonios Tsourdos, Brian White, Madhavan Shanmugavel

Design and Analysis of Composite Structures: With Applications to Aerospace Structures
Christos Kassapoglou

Introduction to Antenna Placement and Installation
Thereza Macnamara

Principles of Flight Simulation
David Allerton

Aircraft Fuel Systems
Roy Langton, Chuck Clark, Martin Hewitt, Lonnie Richards

Computational Modelling and Simulation of Aircraft and the Environment, Volume 1: Platform Kinematics and Synthetic Environment
Dominic J. Diston

Aircraft Performance Theory and Practice for Pilots, 2nd Edition
Peter J. Swatton

Military Avionics Systems
Ian Moir, Allan Seabridge, Malcolm Jukes

Aircraft Conceptual Design Synthesis
Denis Howe

Preface

Sustainable aviation in broad terms means environmentally friendly air travel. This term implies that our current ways are neither sustainable nor environmentally friendly. Fossil‐fuel burning turbofan engines produce greenhouse gases, among other pollutants such as NOx that contribute to the rising temperature on the Earth that is called global warming. Hence, NASA (National Aeronautics and Space Administration) and the European Union’s Advisory Council for Aeronautics Research in Europe (ACARE) work with the aerospace industry and academia to seek alternative solutions to the current state of the art (SOA) in commercial air travel. The solutions by necessity are system‐driven, composed of propulsion and power, airframe, and system integration, air travel management (ATM) and operations. The solutions to the propulsion and power components of sustainable aviation are found in the following:

Fuel burn reduction in advanced‐core ultra‐high bypass (UHB) turbofan engines
Open rotor architecture
Alternative jet fuels from renewable sources
Hybrid‐electric propulsion system
Electric propulsion (EP) with superconducting motors/generators, electric power transmission, energy storage, and the cryogenic thermal management system
Nuclear propulsion through advancements in the next‐generation of compact fusion reactor (CFR)

For airframe and system integration components, sustainable aviation is achieved through:

High lift‐to‐drag ratio (L/D) airplane configurations, e.g. hybrid wing–body (HWB) aircraft
Fully integrated airframe and propulsion system through distributed propulsion (DP) concept
Boundary layer ingesting (BLI) propulsion system and integration
Other drag reduction concepts, e.g. hybrid laminar flow control (HLFC), folding high aspect ratio wings or fluidic actuators

When we consider flight navigation and operations, the roadmap to sustainable aviation is described in the Federal Aviation Administration’s (FAA) vision, called NextGen program. The goal is to develop and implement clean, quiet, and energy efficient operational procedure through the following:

Advanced ATM capabilities
Gate‐to‐gate and surface operational procedures

As we expect from a highly integrated system, it takes all three areas of propulsion and power systems, airframe configuration, and operations to achieve the lofty environmental goals that are set for commercial aviation. The advanced concepts in propulsion and power and the airframe contribute roughly 35–45% to sustainable aviation goals, whereas ATM and operations contribute roughly 15–20%.

Another aviation area of concern is noise pollution. Airport’s neighboring communities are subject to severe restrictions on noise emissions from aircraft takeoff and landing, ground operations, and noise pollution due to airport support vehicles and services. The noise mitigation strategies in sustainable aviation are focused on eight factors:

Airframe noise reduction through BLI propulsion system and control
Landing gear, flaps, and slat noise mitigation in the landing−takeoff (LTO) cycle
Fan noise reduction through lower pressure ratio design and higher bypass ratio engines
Jet noise mitigation through lower‐speed jets, Chevrons, and other means to enhance jet mixing as well as shielding by the airframe
Power management and steep flight path angle in takeoff and landing
Engine noise mitigation through advanced design in swept‐leaned stators in the fan exit duct, advanced acoustic liners, and flow path optimization
Gate and surface support operations
Airport traffic management

This book addresses sustainable aviation concepts and their subsequent promising technologies. It is intended as a resource for students and practicing engineers in aerospace industry. To be useful and self‐contained, I start with a review chapter on aircraft propulsion (Chapter 1), followed by a review chapter on aircraft aerodynamics (Chapter 2). These chapters lay the foundation for the theory, terminology, and science of propulsion and fluid flow. The next four chapters address the essence of sustainable aviation, namely:

Chapter 3: Understanding Aviation’s Impact on the Environment
Chapter 4: Future Fuels and Energy Sources in Sustainable Aviation
Chapter 5: Promising Technologies in Propulsion and Power
Chapter 6: Pathways to Sustainable Aviation

The presentation of the environmental impact of aviation is focused on the science of combustion, radiation physics with respect to greenhouse gases, NOx formation and the ozone layer, contrail formation, aviation‐induced cloudiness (AIC), and radiative forcing (RF). The issues of air‐quality standards and public health and safety are treated as universal concerns. Intentionally, the discussions are more focused on the scientific results and measurements and less on the debate of anthropogenic influences on climate or interference in global warming. We leave that debate, if there is one, to politicians. In this book, we identify the facts of aviation‐related pollution and how we should, as citizen engineers and scientists, help responsibly reduce or eliminate this pollution, by design. The responsibility is especially acute in light of the growth in air travel, namely from 2.5 billion passengers in 2011 to the estimated 16 billion in 2050.

Since the title of the book uses the word Future, I could not limit the presentation in this book to the aircraft that currently fly the commercial aviation routes, i.e. subsonic‐transonic aircraft. At higher speeds, namely supersonic and hypersonic, we briefly address the low‐boom supersonic flight technology as well as some promising propulsion systems for the runway‐to‐orbit or the single‐stage to orbit (SSTO) commercial transport of the future.

Finally, the areas of technology that are presented here are rapidly evolving with new milestones and achievements, e.g. through laboratory and flight tests that appear almost on a monthly (if not weekly) basis in trade journals. The reader is thus encouraged to follow these technological advances and keep up with the current literature. This is certainly an exciting era in aviation.