Cadet Phase I & II
Aerospace Dimensions
Introduction to Flight (Module 1)
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Session 1:
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Chapter 1 ‘Introduction to Flight’
(For all Cadets that have not yet passed corresponding test, and Cadet Mentors)
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Activity
Additional material for Cadet Officers only
Session 2:
Chapter 2 ‘To Fly by the lifting power of rising air’
 Chapter 3 ‘Balloons - They create their own thermals’
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(For all Cadets that have not yet passed corresponding test, and Cadet Mentors)

Activity
Additional material for Cadet Officers only
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
1
Introduction to Flight
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Important Terms (your new ‘language’) (Quiz):
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Aero
Aerodynamics
Aeronautics
Aerospace
AGL
Air
Aircraft
Airplane
Airfoil
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Airport
Altitude
Aviation
Aviator
Camber
Chord
Drag
Dynamic
Leading Edge
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Lift
Relative Wind
Static
Supersonic
Thrust
Trailing Edge
Wind
Aerospace Education: ‘the branch of general education
concerned with communicating knowledge, skills and
attitudes about aerospace activities and the total impact of
air and space vehicles upon society’
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
2
Introduction to Flight
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Daedalus & Icarus
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Marco Polo
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Greek mythology: Father and son escaped imprisonment by
fashioning wings from feathers and beeswax, and flying away
 Icarus was said to have flown too close to the sun, which
melted the beeswax, and his wings fell apart
Reported seeing Chinese sailors strapped under huge kites,
and used as aerial observers
Montgolfier Brothers
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Designed first confirmed manned balloon
to actually fly (burner = power)
Flown by d’Rozier and d’Arlandes in Paris
France Nov 21st 1783
(Note: just 7 years after US declaration of Independence!)
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
3
Introduction to Flight

Daniel Bernoulli (1700-1782, Dutch)
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When air is accelerated, its pressure drops
 Sir Isaac Newton (1643-1727, English)
An object at rest will remain at rest unless acted upon by
some outside force
 THRUST (Propeller or Jet) needed for the plane to move
2 A force acting upon a body causes it to accelerate in the
direction of the force. Acceleration is directly
proportional to the mass of the body being accelerated
 Prop or Jet causes acceleration, more power = more speed
1
(what would happen if you strapped a jet to a Cessna 172?)
3
For every action, there is an equal and opposite reaction
 Jet points backwards, but plane goes forward
 And air impacting under the wing causes the wing to rise
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
4
Introduction to Flight
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Bernoulli in action: The Airfoil
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Because it has to travel
further, the air over the top
of the wing ‘travels’ faster,
and so is at lower
pressure than the air under the wing, and that = LIFT!
 This ‘traveling’ air (airflow) is called the Relative Wind
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LIFT = CL x R x ½V² x A
 CL - Coefficient of lift ~ defined by angle of attack and airfoil
design
 R - Density of air (mass/volume) ~ more dense = more lift
 ½V² - ½(Velocity of air)² ~ air speed x2 = lift x4
 A - Area of Wing ~ average chord x wing span
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
5
Introduction to Flight
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How do the theories of Bernoulli and Newton apply to
a bird?
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Birds create ‘thrust’ by flapping and controlling the
angle of their wings (Dynamic Lift)
 They control their feathers to trap air on the downbeat, but
allow it through on the upbeat (Newton 1 AND 2)
 Also, by tilting the wing upward, Newton’s 3rd law provides
additional lift
 A bird’s wing has an airfoil
like cross-section, so air
MUST move faster over
than under, which
created lower
pressure on top
= Bernoullian Lift (Induced)
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
6
Introduction to Flight
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Four Main Forces acting on an Airplane in Flight:
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To stay aloft, Lift MUST = Weight (Mass x Gravity)
 To accelerate, Thrust MUST be GREATER than Drag
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
7
Introduction to Flight
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How can you get MORE lift from a wing?
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Make a Bigger Wing (Area increases {remember lift equation})
 (Flaps can do this temporarily)
 Increase the Curve of the upper camber (CL increases)
 (Flaps also do this temporarily. They provide additional lift
at the lower speeds of Take off and Landing)
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Increase Speed (½V² increases)
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Increase the Angle of Attack (CL increases)
 Like when the pilot pulls back on the stick at takeoff
 BUT, go too far
(over about 17°)
and the wing will ‘stall’
i.e. airflow over top of wing
separates. A wing stalls at its Critical Angle of Attack
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
8
Introduction to Flight
 Airplane Components:
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
9
Introduction to Flight
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The Three
Axes of an
Airplane:
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Movement around
Lateral Axis = Pitch
 caused by Elevator
movements
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Movement around Vertical Axis = Yaw
 caused by Rudder movements
 Movement around Longitudinal Axis = Roll
 caused by Aileron movements
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
10
Introduction to Flight

So what does a Propeller do, and how?
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A Propeller creates thrust that causes the airplane to
move forward
 It is a wing, on its edge, moving in a fixed circle, creating
its own relative wind
 Because of its airfoil shape, it creates lower pressure on
the forward edge, which results in forward lift, which pulls
it (and the attached airplane forward)
– Question - how can the propeller create more thrust (lift)?
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Aerodynamics of a Propeller (why the funny shape?):
 Design tries to equalize the thrust (lift) along the blade
 1 = Hub (attachment point, no lift)
 2,3,4 = Main Blade (each is faster,
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so blade gets progressively flatter)
5 = Tip (fastest point, so lowest
curve)
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
11
To Fly by the lifting power of rising air
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Important Terms:
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Altitude
 AGL or MSL
Aspect Ratio
 Wing Span : Chord
Convection
 Fluid motion due to temp differences
Density
 Mass/Volume
Glide Ratio
 How far forward per unit of descent
Lapse Rate
 temp decrease / altitude increase
Lift-to drag Ratio
 gliding efficiency
Soaring
 staying up on natural energy
 Span
 distance between wingtips
 Spoilers
 wing lift reducers (Dive Brakes)
 Stability
 atmosphere resistance to
vertical motion
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Thermal
 rising column of air
 Tow Plane
 plane providing initial thrust
and altitude ‘gift’ for a glider
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Wave
 up and down air currents from
air flow over mountains
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
12
To Fly by the lifting power of rising air
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How rising air provides LIFT for flight:
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Heat from the sun (93 Million Miles away!), causes air to warm
up and rise
Heated air rises because it becomes less dense (molecules
move more, and push each other further apart), and so this air
is now lighter than surrounding air
The upper atmosphere is quite cold, so eventually this rising
air cools, and falls again
The rising and falling motion
is called convection
When the atmosphere resists
convection, it is said to be stable
Cooling with altitude is
called the Lapse Rate, which
is about 3½°F for every
1000ft up
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
13
To Fly by the lifting power of rising air
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Gliders and Sailplanes
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Sailplanes can ride the columns of warm rising air, and stay
aloft by soaring on the free solar energy
Gliders do not soar, but they do have a
higher glide ratio
than conventional
powered
airplanes
Both Gliders
and
Sailplanes
must
first be
towed to
altitude
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
14
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Balloons - They create their own thermals
Important Terms:
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Balloon - Aircraft lifted by lighter than air gas, with no means of
horizontal control
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Burner - Device which heats air (hot air is lighter than surrounding air)
Buoyancy - Rising or Floating in a fluid (such as air or water)
Crown - Top of a Balloon’s ‘Envelope’
Envelope - The main body of a balloon (usually nylon)
Gore - The vertical panels that make up the envelope
Montgolfier - French brothers who created first successful manned
balloon
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Parachute Panel - Device inside top of envelope, allows hot air to
escape when required
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Propane - Lightweight fuel for burner
Thermistor - Device which measures temp inside envelope
Variometer - Vertical Velocity Indicator (Rate of Climb/Descent)
Wicker - Woven wood used to make the basket (Gondola)
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
15
Balloons - They create their own thermals
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How a Balloon flies:
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Buoyancy - Hot Air is Lighter than Cold air, so it rises above it
Trap enough hot air inside the envelope, and the buoyancy can
lift both the air itself, and the balloon and passengers too
To Rise - The envelope’s air is heated by the Propane Burner
To Descend - Hot air can be ‘let out’ through a vent at the top of
the envelope by partially collapsing the Parachute
Directional control comes from natural wind, which moves in
different directions at different altitudes - So the pilot must
climb/descend to find a wind going in the required direction
 The Math of a Balloon’s Lift:
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Hydrogen balloon (like the Hindenburg) ~ 60lb LIFT per 1,000 cu ft
Hot Air balloon ~ 17 - 20lb LIFT per 1,000 cu ft
77,000 cu ft balloon LIFT = 17 x 77 = 1309lb ( minus about 600lb
for envelope + basket, burner and propane = 709lb payload )
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
16
Balloons - They create their own thermals
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Balloon Components
(6 - 18 feet wide)
Load
Tapes
support
the envelope,
and maintain its
shape (ideally
spherical)
Typical materials
are Nylon &
Dacron, with a
Polyurethane
coating
Several MILLION
BTU’s per Hour
(1 BTU = raise 1 lb
water by 1°F)
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
Typical Instruments are
Thermistor, Variometer
(Vertical Velocity Indicator),
and Altimeter
17
Balloons - They create their own thermals
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Hydrogen balloon example (not for test)
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Hindenburg the Largest Aircraft EVER to Fly
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Gas volume 7,062,000 cubic feet!!
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LIFT = 60 x 7062 = 423,720lb (212 TONS!! Actually quoted as
242 Tons)
Minus about 260,000lb for structure and fuel = 112 Tons useful
payload!!
 That’s the Gross Weight
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of a Boeing 757-200!
 Only 9% shorter than the
Titanic!
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She was destroyed by fire
while arriving at NAS
Lakehurst NJ, May 6, 1937
Now known that fire was due to
flammable skin NOT Hydrogen
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
18