National Aviation College
Course Title: Aircraft Performance
Course Code: AVMT 311
Credit Hrs. 4
April 2022
Course Contents
Chapter 1: Introduction (5Hrs)
Chapter 2: The General Performance Problems (6Hrs)
Chapter 3: Basics of Aircraft Performance (5Hrs)
Chapter 4: Climbing Flight performance (5Hrs)
Chapter 5: Range and Endurance (3Hrs)
Chapter 6: Factors affecting aircraft performance (4Hrs)
Chapter 7: Performance and Altitude (4Hrs)
Chapter 8: Non-steady Flight in the Vertical Plane (3Hrs)
Chapter 9: Manoeuvring Flight (3Hrs)
References and Textbooks
• Textbooks:
1. Maido Saarlas. Aircraft Performance, Department of Aerospace, 2007.
2. Mario Asselin. An Introduction to Aircraft Performance, 1997.
3. Countland D. Perkins. Airplane performance, stability and control. 1976
• Reference books:
1. J Anderson. Fundamentals of aerodynamics, 3rd edition, 1987
2. Pilot’s handbook of Aeronautical Knowledge, FAA-H-8083, 2008
3. M.V. Cook. Flight dynamics principles, 2nd edition, 2007.
Method of Assessment
 Continuous Assessment: (Quiz after completion of each Chapter,
Individual Assignments, Group Assignment, Final Exam)
Objectives
After complete this course the student will be able to:
 State the use of Aircraft Performance Data
 Explain the earth’s atmosphere and its parameters
 Explain the effect of atmospheric parameters on the
aerodynamic forces
 Explain factors affecting aircraft performance
 Explain the Items of Aircraft Performance
 Describe Aircraft performance
1. Introduction
The invention and development of the airplane is one of
the most important technical developments of the
twentieth century.
The airplane has transformed life in the twentieth
century, and this transformation continues.
However, the airplane did not just "happen." When you
see an aircraft in the sky, you are observing the resulting
action of the natural laws of nature that govern flight.
The human understanding of these laws of flight did not
come easily-it has evolved over the past 2,500 years,
starting with ancient Greek science.
In December 1903 that these laws were finally harnessed by human
beings to a degree sufficient to allow a heavier-than-air, powered,
human-carrying machine to execute a successful sustained flight
through the air.
Orville and Wilbur Wright, with pride and great satisfaction, reaped
the fruits of their labours and became the first to fly the first
successful flying machine.
The airplane is the subject of this Course-its performance and its
(design).
The purpose of this course is to pass on to you an appreciation "Of
the laws of flight, and the embodiment of these laws in a form that
allows the understanding and prediction of how the airplane will
actually perform in the air (airplane performance) and how to
approach the creation of the airplane in the first place in order to
achieve a desired performance or mission.
Therefore, the purpose of this course is to present the elements of
performance and to do so in such fashion as to give you both a technical and a
philosophical understanding of the process.
The Wright Flyer, at the moment of lift-off on its first Right, December 17, 1903.
Four Historical Periods Of Airplane Design
Characteristics
Reading Assignment
Page 6 to 19: “Aircraft Performance and Design, John D.
Anderson, Jr”
Absolute Performance Characteristics
The first group, called the absolute performance characteristics, are of
the primary interest to the designer. They are called absolute because
they are simply numbers representing the capabilities of the aircraft.
The most important are:
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Maximum speed
Stalling speed
Best climbing speed
Best glide speed
Rate of climb
Ceiling(s)
Maximum range and speed for maximum range
Maximum endurance and speed for maximum endurance
Take-off distance
Landing distance
The earth’s atmosphere
Atmosphere is the mixture of gases, water droplets and solid
particles above the surface of the Earth.
Earth’s atmosphere stretches from the surface of the planet up to
as far as 10,000 kilometres above.
After that, the atmosphere blends into space.
Earth’s atmosphere is composed of
about 78 percent nitrogen, 21 percent
oxygen, 0.9 percent argon, and 0.1
percent other gases. Trace amounts of
carbon dioxide, methane, water vapor,
and neon are some of the other gases
that make up the remaining 0.1 percent.
The Vertical Structure of the atmosphere
The atmosphere is divided into five different layers, based on
temperature variation.
 The main layers to know are:
The troposphere
The stratosphere
 The mesosphere
The thermosphere
The exosphere
The Troposphere
Surface to roughly 10 km
~3/4 of mass of atmosphere in this layer
Most weather occurs in this layer
Temperature generally decreases with height in this layer (by ~6.5C
per km)
The top of troposphere is called the tropopause. Midlatitude jet
stream tends to be strongest near the tropopause.
Above the tropopause is the stratosphere.
The Stratosphere
10-50 km above the surface
Temperature constant or INCREASING with height
Stable (not a lot of vertical mixing) and dry
Only occasionally get overshooting tops from convection pushing
into this layer
 The Stratosphere Is Where Jets Like to Fly.
 The lower boundary of the stratosphere is called the tropopause; the
upper boundary is called the stratopause.
 The stratosphere is very dry air and contains little water vapor.
Because of this, few clouds are found in this layer and almost all
clouds occur in the lower, more humid troposphere.
Stratospheric Ozone Layer
Maximum ozone (O3) between 20 and 30 km.
Protects the surface from harmful ultraviolet (UV) radiation
Ozone is produced photochemically
A photochemical reaction
is a chemical reaction in
which radiation affects the
chemical composition of a
substance.
Mesosphere (50-80 km)
A second region of temperature decline with
height.
Why? Getting away from ozone heating
The mesosphere is a layer of Earth's
atmosphere. The mesosphere is directly above
the stratosphere and below the thermosphere.
It extends from about 50 to 85 km above the
surface of the Earth.
The Thermosphere
Extends 80-140km above the surface of the
Earth.
A region where temperature increases with
height.
Warming produced by absorption of shortest
wavelength ultraviolet components in upper
troposphere by 02, ), N, N2
• Aurora in this layer
The Exosphere
The exosphere is the uppermost region of Earth's atmosphere as it
gradually fades into the vacuum of space.
The air in the exosphere is extremely thin - in many ways it is
almost the same as the airless void of outer space.
Not all scientists agree that the exosphere is really a part of the
atmosphere.
Some scientists consider the thermosphere the uppermost part of
Earth's atmosphere, and think that the exosphere is really just part
of space.
 Although the exosphere is technically part of Earth's atmosphere,
in many ways it is part of outer space. Many satellites, including the
International Space Station (ISS), orbit within the exosphere or
below.
Atmospheric pressure
The air around us has weight, and it presses against everything it touches.
That pressure is called atmospheric pressure, or air pressure.
 It is the force exerted on a surface by the air above it as gravity pulls it to
Earth.
Atmospheric pressure is commonly measured with a barometer. In a
barometer, a column of mercury in a glass tube rises or falls as the weight
of the atmosphere changes.
Meteorologists describe the atmospheric pressure by how high the
mercury rises.
An atmosphere (atm) is a unit of measurement equal to the average air
pressure at sea level at a temperature of 15 degrees Celsius.
One atmosphere is 1,013 millibars, or 760 millimetres (29.92 inches) of
mercury.
 Atmospheric pressure drops as altitude increases.
Atmospheric pressure …
As the pressure decreases, the amount of oxygen available to
breathe also decreases.
At very high altitudes, atmospheric pressure and available oxygen get
so low that people can become sick and even die.
 Mountain climbers use bottled oxygen when they ascend very high
peaks. They also take time to get used to the altitude because quickly
moving from higher pressure to lower pressure can cause
decompression sickness.
 Aircraft create artificial pressure in the cabin so passengers remain
comfortable while flying.
Pressure Altitude (PA)
It is the altitude indicated by an
altimeter adjusted to 29.9 inHg.
 Pressure altitude and flight level are
always equal.
How to Calculate Pressure Altitude (PA)
1. Set the altimeter to 29.9inHg, and the altitude you
read is the PA.
2. Using Current QNH and Airport Elevation
PA=(1013-QNH)X27+Elevation
Example
The QNH at a certain Airport is 1002hPa and the Airport Elevation is
50ft. What is the pressure altitude?
Soln.
PA=(1013-1002)X27+50 = 297 feet
Density Altitude (DA)
The density altitude is the altitude relative to standard atmospheric conditions
at which the air density would be equal to the indicated air density at the place
of observation.
In other words, the density altitude is the air density given as a height above
mean sea level (MSL).
The density altitude can also be considered to be the pressure altitude
adjusted for a non-standard temperature.
Both an increase in the temperature and a decrease in the atmospheric
pressure, and, to a much lesser degree, an increase in the humidity, will cause an
increase in the density altitude.
In hot and humid conditions, the density altitude at a particular location may be
significantly higher than the true altitude.
Density Altitude …
In aviation, the density altitude is used to assess an aircraft's aerodynamic
performance under certain weather conditions.
The lift generated by the aircraft's aerofoils, and the relation between its
indicated airspeed (IAS) and its true airspeed (TAS), are also subject to airdensity changes.
Furthermore, the power delivered by the aircraft's engine is affected by the
density and composition of the atmosphere.
How to Calculate Density Altitude
DA=PA+120XISA dev
Where, ISA dev = OAT- ISA
ISA = 15oC
Reading Assignment
• Effect of pressure on density
• Effect of temperature on density
• Effect humidity (moisture) on density
 Next Topic
Chapter 2. The General Performance Problems