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MEE 225 Intro to Flight

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My General Interest in Aerospace Engineering

Air transport carbon footprint is relatively small

Global CO2 Emissions

Other industry2%

Industrial processes3%

Cement5%

Chemicals6%

Air transport2%

Other transport2%

Other electricity and heat12%

Other energy10%

Building light and heat20%

Land use change & forestry

25%

Road transport 13%

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But Carbon Footprint is Growing

Future traffic growth: ~5.2% p.a.

Reduction in emissions: ~2% p.a.

Minimal Goal: Decouple traffic and emissions growth

Constrains: Safety first Long implementation timelines Single fuel technology Dependence on governments

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Emission Road Map

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Facts and Figures

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COMMERCIAL AIRCRAFT: BOEING SERIES

• What is the same?• What is different?• Why?

707

727

737

747

757

767

777

787

BOEING 747-110 (1973) vs. 747-800 (2009)

LECTURE TOPICS: AERODYNAMICS

SR-71

Boeing 777

U-2 F-15

• Why are airplanes, wings, rockets, etc. shaped the way they are?

• What is the relevance of their shape?

• How do we design such shapes and what is the impact of that design?

WHY CAN A HEAVIER-THAN-AIR CRAFT FLY?

Why do airfoils have such a shape?

How are lift and drag produced?

How do we design?

What is limit of behavior?

SLATS AND FLAPS

SWEPT WINGS

• All modern high-speed aircraft have swept wings: WHY?

AIRCRAFT WAKE TURBULENCE

WINGLETS

DO YOU NEED WINGS TO FLY?"At some point I collided with one of the Skyhawks, at first I didn't realize it. I felt a big strike, and I thought we passed through the jet stream of one of the other aircraft. Before I could react, I saw the big fireball created by the explosion of the Skyhawk.”

SUPERSONIC FLOW• Can you fly faster than the speed of sound, HOW?• What can happen in supersonic flows?• Supersonic flows (M > 1) are qualitatively and quantitatively different

from subsonic flows (M < 1)

OTHER APPLICATIONS OF AERODYNAMICS

LECTURE TOPICS: AIRPLANE PERFORMANCE

• How does this airplane perform– How fast can this airplane fly?

– How far can this airplane fly on a single tank of fuel (Range)?

– How long can this airplane stay in the air on a single tank of fuel (Endurance)?– How fast and how high can it climb?– How well can the airplane maneuver?

747

7E7

What drove this design?

VIRGIN ATLANTIC GLOBALFLYER

World record for first non-stop solo circumnavigation around the world

Wing Span: 114 ftWing Area: 400 ft2

Length: 44.1 ftHeight: 13.3 ftGross Weight: 22,000 lbsEmpty Weight: 3,350 lbs

LECTURE TOPICS: ROCKET VS. AIR-BREATHING PROPULSION

• Take mass stored in a vehicle and throw it backwards

→ Use reaction force to propel vehicle

All fuel and oxidizer are carried onboard the vehicle

• Capture mass from environment and set that mass in motion backwards

→ Use reaction force to propel vehicle

Only fuel is carried onboard

Oxidizer (air) is ‘harvested’ continuously during flight

CROSS-SECTIONAL EXAMPLE: GE 90-115B

• Why does this engine look the way that it does?

• How does this engine push an airplane forward, i.e. how does it generate thrust?• What are major components and design parameters?

Compressor

Combustor

Turbine

Fan

Inlet

Nozzle

TRENDS TO BIGGER ENGINES

1958: Boeing 707, United States' first commercial jet airliner 1995: Boeing 777, FAA Certified

PW4000-112: T=100,000 lbf , Bypass ratio α ~ 6

Similar to PWJT4A: T=17,000 lbf, Bypass ratio α ~ 1

COMMERCIAL VS. MILITARY ENGINES(APPROX. SAME THRUST, APPROX. CORRECT RELATIVE SIZES)

GE CFM56 for Boeing 737T~30,000 lbf, Bypass Ratio, α ~ 5

P&W 119 for F- 22, T~35,000 lbf, Bypass Ratio α ~ 0.3

SCRAMJET PROPULSION: X-43 MACH 10!

LECTURE TOPICS: ROCKETSBell X-1: XLR11

HOW ARE ROCKET NOZZLES SHAPPED?

• Converging-Diverging shape is ONLY way to accelerate a sub-sonic flow to super sonic velocities!