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Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 1 Cadet Phase I & II Aerospace Dimensions Introduction to Flight (Module 1)  Session 1:  Chapter.

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Presentation on theme: "Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 1 Cadet Phase I & II Aerospace Dimensions Introduction to Flight (Module 1)  Session 1:  Chapter."— Presentation transcript:

1 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 1 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:  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

2 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 2 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  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’  Lift  Relative Wind  Static  Supersonic  Thrust  Trailing Edge  Wind

3 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 3 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!)

4 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 4 Introduction to Flight  Daniel Bernoulli ( , Dutch)  When air is accelerated, its pressure drops  Sir Isaac Newton ( , English) 1 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 (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

5 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 5 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 lower pressure than the air under the wing, and that = LIFT!  This ‘traveling’ air (airflow) is called the Relative Wind  LIFT = C L x R x ½V² x A  C L - 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

6 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 6 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’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)

7 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 7 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

8 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 8 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 (C L 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 (C L 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

9 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 9 Introduction to Flight  Airplane Components:

10 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 10 Introduction to Flight  The Three Axes of an Airplane:  Movement around Lateral Axis = Pitch  caused by Elevator movements  Movement around Vertical Axis = Yaw  caused by Rudder movements  Movement around Longitudinal Axis = Roll  caused by Aileron movements

11 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 11 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)

12 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 12 To Fly by the lifting power of rising air  Important Terms:  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  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

13 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 13 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

14 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 14 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 ratio than conventional powered airplanes  Both Gliders and Sailplanes must first be towed to altitude

15 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 15 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)

16 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 16 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 ~ lb 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 )

17 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 17 Balloons - They create their own thermals  Balloon Components ( feet wide) Typical materials are Nylon & Dacron, with a Polyurethane coating Typical Instruments are Thermistor, Variometer (Vertical Velocity Indicator), and Altimeter Load Tapes support the envelope, and maintain its shape (ideally spherical) Several MILLION BTU’s per Hour (1 BTU = raise 1 lb water by 1°F)

18 Dr. R.A. Bartholomew - Civil Air Patrol, New Jersey Wing 18 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 !  Only 9% shorter than the Titanic!  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


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