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Cadet Phase I & II Aerospace Dimensions Introduction to Flight (Module 1). Session 1: Chapter 1 ‘Introduction to Flight’ (For all Cadets that have not yet passed corresponding test, and Cadet Mentors) Activity Additional material for Cadet Officers only Session 2:

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Cadet Phase I & II Aerospace Dimensions Introduction to Flight (Module 1)

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Cadet phase i ii aerospace dimensions introduction to flight module 1 l.jpg

Cadet Phase I & IIAerospace DimensionsIntroduction to Flight (Module 1)

Session 1:

Chapter 1 ‘Introduction to Flight’ (For all Cadets that have not yet passed corresponding test, and Cadet Mentors)

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’ (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


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Introduction to Flight

  • Important Terms (your new ‘language’) (Quiz):

  • Aero

  • Aerodynamics

  • Aeronautics

  • Aerospace

  • AGL

  • Air

  • Aircraft

  • Airplane

  • Airfoil

  • Airport

  • Altitude

  • Aviation

  • Aviator

  • Camber

  • Chord

  • Drag

  • Dynamic

  • Leading Edge

  • 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


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Introduction to Flight

  • Daedalus & Icarus

    • 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

  • Marco Polo

    • Reported seeing Chinese sailors strapped under huge kites, and used as aerial observers

  • Montgolfier Brothers

    • 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


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Introduction to Flight

  • Daniel Bernoulli (1700-1782, Dutch)

    • 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

    • 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(what would happen if you strapped a jet to a Cessna 172?)

    • 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


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Introduction to Flight

  • Bernoulli in action: The Airfoil

    • Because it has to travel further, the air over the top of the wing ‘travels’ faster, and so is at lowerpressure than the air under the wing, and that = LIFT!

      • This ‘traveling’ air (airflow) is called the Relative Wind

    • 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


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Introduction to Flight

  • How do the theories of Bernoulli and Newton apply to a bird?

    • 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’s3rd 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


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Introduction to Flight

  • Four Main Forces acting on an Airplane in Flight:

    • 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


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Introduction to Flight

  • How can you get MORE lift from a wing?

    • 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)

    • Increase Speed (½V² increases)

    • 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


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Introduction to Flight

  • Airplane Components:

Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing


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Introduction to Flight

  • The Three Axes of an Airplane:

    • Movement around Lateral Axis = Pitch

      • caused by Elevatormovements

    • 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


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Introduction to Flight

  • So what does a Propeller do, and how?

    • 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)?

    • 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, so blade gets progressively flatter)

  • 5 = Tip (fastest point, so lowest curve)

Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing


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To Fly by the lifting power of rising air

  • Important Terms:

  • Soaring

    • staying up on natural energy

  • Span

    • distance between wingtips

  • Spoilers

    • wing lift reducers (Dive Brakes)

  • Stability

    • atmosphere resistance to vertical motion

  • Thermal

    • rising column of air

  • Tow Plane

    • plane providing initial thrust and altitude ‘gift’ for a glider

  • Wave

    • up and down air currents from air flow over mountains

  • 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

Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing


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To Fly by the lifting power of rising air

  • How rising air provides LIFT for flight:

    • 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


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To Fly by the lifting power of rising air

  • Gliders and Sailplanes

    • 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 ratiothan conventional powered airplanes

    • Both Gliders and Sailplanes mustfirst be towed to altitude

Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing


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Balloons - They create their own thermals

  • Important Terms:

    • Balloon - Aircraft lifted by lighter than air gas, with no means of horizontal control

    • 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

    • Parachute Panel - Device inside top of envelope, allows hot air to escape when required

    • 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


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Balloons - They create their own thermals

  • How a Balloon flies:

    • 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:

    • 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


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Balloons - They create their own thermals

  • Balloon Components

(6 - 18 feet wide)

Load Tapes support the envelope, and maintain its shape (ideally spherical)

Typical Instruments are Thermistor, Variometer (Vertical Velocity Indicator), and Altimeter

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


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Balloons - They create their own thermals

  • Hydrogen balloon example (not for test)

    • Hindenburg the Largest Aircraft EVER to Fly

    • Gas volume 7,062,000 cubic feet!!

    • 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 of a Boeing 757-200!

      • Only 9% shorter than the Titanic!

    • She was destroyed by firewhile 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


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