1 Challenge the future

Introduction to Aerospace Engineering

Lecture slides

15-12-2012

Challenge the future

Delft University of Technology

Intro to Aerospace Engineering AE1101 Intro, Ballooning

Prof.dr.ir. Jacco Hoekstra

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Set-up of course AE1101/AE1102

Intro to AE

First Semester

Period I & II

Theme ‘Exploration’

Exam AE1101 Oct

Exam AE1102 Jan

AE1101 ab Intro Aeronautics

AE1101 e Aerodynamics

AE1101 f Flight Dynamics

AE1102 cd Intro Space

AE1102 f Orbital Mechanics

AE1102 g Materials & Structures

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4 AE1101 Introduction to Aerospace Engineering |

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• Books:

• Introduction to Flight – John D. Anderson, 6th edition, McGraw Hill

international edition, 6ht or 7th

• Hand-outs:

• Blackboard: http://studenten.tudelft.nl > blackboard > login > Enroll

AE1101

• Sometimes printed at lectures

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Role of Aviation for society (numbers for 2007)

• 2.5 billion passengers annually (average nr of km flown per

person is about 320 km per year globally)

• 50 million tonnes of freight

• 15 million jobs (excl. tourism 16 million jobs, etc.)

• Turnover aviation 1 US$ trillion (=million million 1012; “biljoen”),

• 145% growth between 2007 and 2026 expected

• 35% of value of trade of manufactured goods was transported by

air

• R&D spending in aerospace generates 170% benefit for GDP

Source: “Aviation, The Real World Wide Web” Oxford Economics

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Principles of flight? Three ways to counter gravity… do you any other?

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Principles of flight? Three ways to counter gravity… do you any other?

Push air downwards Push something else downwards

Floating by being lighter

He / Hot Air

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KongMing Lantern

孔 明 燈

• First hot air balloons

• Used for military communications

and/or surveillance

Zhuge Liang (Kong Ming) China: 200 – 300 AD

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Principle of floating exploited with hot air (although they thought it was a special gas)

21 Nov 1783

After duck, rooster and sheep First manned flight on Nov 21, 1783 by a young physician, Jean-François Pilâtre de Rozier and an army officer, François Laurent d'Arlandes

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Today’s balloons: essentially the same

Con: - slow - high drag (not so green?)

Rigid airship

Pro: - Very efficient lift - Can go very high

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Ballooning/aerostatics

• Which type provides more lift? Helium or hot air? Why?

• How many helium-filled party balloons can you safely ‘carry’

before you become airborne? 50-100-1000-10,000?

• What altitude can you reach with a balloon?

• How does the balloon know what’s up if there is an equilibrium of

forces inside and outside across the surface?

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Two laws (blackboard):

• Gas law => equation of state

• Archimedes law

• Lift formulae balloons

• 1 party balloon = 0.0141 m3 according to spec supplier

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Ideal Gas Law

R = 8.3145 J/mol K

Mair = 28.97 g/mol = 0.02897 kg/mol

Rair = 8.3145/0.02897 = 287.0 J/kg K R = 287.0

air

p V n R T

p R T

p RT

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Aerostatics (N.B. not in Anderson!)

Netto lift:

With air there was equilibrium, hence force on body with volume Q:

Hot air balloon:

Gas balloon: MHe = 4.00 g/mol

MH2 = 2.02 g/mol Mair = 28.97 g/mol

ρatm = 1.225 kg/m3 Tatm = 150C= 288.15 K

Typical V hot air balloon = 2500 m3

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Priest Adelir Antonio di Carli, April 2008

Effects of atmospheric conditions…

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• www.hollandshoogte.nl by Tim Zaman

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• www.hollandshoogte.nl by Tim Zaman

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Homework • Exercises in balloon hand-out problem 1-6

• Anderson exercises (page 102-103):

• 2.1 (only density)

• 2.7

• 2.11 (Note: 1 slug/ft3 = 515.4 kg/m3)

• Optional: 2.12, 2.13, 2.14

Read sections 3.1 – 3.4