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

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

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

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

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 = 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

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

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

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

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

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

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

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

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

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

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

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

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

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 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