For Video Lecture of this presentation: https://youtu.be/DqaoNt0LoIE The topics covered in this session are, Properties of Atmosphere, International Standard Atmosphere (ISA) definition and derivation, ISA Chart. The formula for obtaining ISA Chartar completely derived from basic equations. Attention! "Gate Aerospace Engineering aspirants", A virtual guide for gate aerospace engineering is provided in "Age of Aerospace" blog for helping you meticulously prepare for gate examination. Respective notes of individual subjects are provided as 'Embedded Google Docs' which are frequently updated. This comprehensive guide is intended to efficiently serve as an extensive collection of online resources for "GATE Aerospace Engineering" which can be accessed free of cost. Use the following link to access the study material https://ageofaerospace.blogspot.com/p/gate-aerospace.html

1. FLIGHT MECHANICS
ATMOSPHERE: PROPERTIES & STANDARD ATMOSPHERE
Presented by - Ganesh Natarajan S
Target Audience: Gate Aerospace, Aerospace and Aeronautical Engineering Students, etc.

2. • Atmosphere: Properties
• Three major properties
• Variation with altitude
• Standard Atmosphere
• Deriving the properties of ISA
o For Isothermal Region
o For Gradient Region
• ISA Chart
Outline
Let’s Start
ATMOSPHERE: PROPERTIES & STANDARD ATMOSPHERE
Previous Lesson Atmosphere Altitude

3. Atmosphere: Properties
Variation of properties with altitude
• Pressure decreases with increasing altitude.
• Density decreases with increasing altitude.
• Temperature varies relatively with increasing
altitude.
• The “Temperature” is obtained experimentally.
ByCmglee-Ownwork,CCBY-SA3.0
• Pressure
• Density
• Temperature
Altitude

4. STANDARD ATMOSPHERE
Definition:
A static atmospheric model providing mean values of pressure, density and temperature
change along the altitude range is known as the standard atmosphere.
Regions of standard atmosphere:
• Gradient region
• Isothermal region
Lapse Rate:
The rate at which temperature varies with altitude is
known as the “Lapse Rate.”

5. Deriving the properties of ISA (International Standard Atmosphere)
• The pressure p, density ρ, and temperature T are dependant on altitude.
• For the case of ISA (International Standard Atmosphere) temperature is obtained from
experimental data.
• If the temperature T(h) is known, then the pressure p(h) and density ρ(h) can be obtained
as follows.

12. Altitude Pressure Temperature
feet metre (Hg) Pascal (°C) Kelvin (°F)
0 0 29.9 101309 15 288.2 59
1,000 304.8 28.9 97720 13 286.2 55.4
2,000 609.6 27.8 94198.5 11 284.2 51.9
3,000 914.4 26.8 90812.5 9.1 282.3 48.3
4,000 1219 25.8 87494.2 7.1 280.3 44.7
5,000 1524 24.9 84277.5 5.1 278.3 41.2
6,000 1829 24 81196.3 3.1 276.3 37.6
7,000 2133 23.1 78182.7 1.1 274.3 34
8,000 2438 22.2 75236.9 -0.9 272.3 30.5
9,000 2743 21.4 72392.7 -2.8 270.4 26.9
10,000 3048 20.6 69650 -4.8 268.4 23.3
11,000 3353 19.8 67008.9 -6.8 266.4 19.8
12,000 3657 19 64401.7 -8.8 264.4 16.2
13,000 3962 18.3 61929.9 -11 262.4 12.6
14,000 4267 17.6 59492 -13 260.5 9.1
15,000 4572 16.9 57155.7 -15 258.5 5.5
16,000 4877 16.2 54887.1 -17 256.5 1.9
17,000 5181 15.6 52686.2 -19 254.5 -1.6
18,000 5486 14.9 50586.8 -21 252.5 -5.2
19,000 5791 14.3 48521.4 -23 250.6 -8.8
20,000 6096 13.7 46523.6 -25 248.6 -12
ByCmglee-Ownwork,CCBY-SA3.0
ISA CHART

13. Book Reference
• Introduction to Flight (7th Edition) - John D. Anderson -
Pg.No: (110-133/945)
• Aircraft Performance & Design - John D. Anderson –
Pg.No: (545-565)
ATMOSPHERE: PROPERTIES & STANDARD ATMOSPHERE

14. Summary
Properties
Standard
Atmosphere
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