Glider - PowerPoint

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 Parts of a Glider
    The glider has four main parts:
                                      Fuselage – the body of the plane

Control Surfaces
– movable sections                                       Wings
 of the wing & tail
                      Landing Gear – usually
                        just a single wheel                      From
Gliders Through History
   The Wright brothers perfected early aircraft designs
    through a series of glider flights in the early 1900’s
   During WWII, the military used gliders to carry and
    land troops
   Many of today’s sophisticated gliders can stay aloft
    for hours
   The Space Shuttle flies as a glider during reentry
    and landing

      From   From
               brothers/huffaker-glider.bmp              shuttles-and-reusable-launch-vehicles.htm
Forces of Flight
   Four forces act on an airplane

Forces of Flight (cont.)
   Weight – This force is caused by
    gravitational attraction to the earth
       Weight depends on the mass of the
        airplane, plus its payload
       Weight resists flight
   Lift – This force is created by the
    motion (velocity) of the airplane
    through the air
       Lift overcomes weight to make the      From
        plane fly
       Most of the lift is generated by the
        wings (through their design & angle)
Forces of Flight (cont.)
   Drag – As an airplane moves
    through the air, the air opposes its
    motion, creating drag
       This force acts in the opposite
        direction of the plane’s flight
       The shape and velocity of the plane
        and the properties of the air around
        the plane affect drag
       Drag resists flight
   Thrust – This force is created by a        From
    propulsion system (engine,                 12/airplane/forces.html

       Thrust overcomes drag to make the
        plane fly
Gliders and Thrust
   Gliders have no propulsion system, and therefore
    nothing to generate thrust
       No force opposes drag in a glider
       A glider will slow down until it can no longer generate
        enough lift to oppose weight

Only 3 forces act on a glider:
1. Lift
2. Weight
3. Drag
How does a glider fly?
   As just mentioned, gliders have no propulsion system
   Gliders are generally towed by another plane to a certain
    altitude, and then launched
   Gliders then trade altitude for velocity
       At its initial altitude, the glider has stored potential energy
   Potential energy is converted to kinetic energy as the plane
       This kinetic energy comes in the form of velocity

How does a glider fly? (cont.)
Glider Design
   Engineers must consider a number of factors
    when designing a glider:
       Weight
           Will a heavy glider or a light glider be more effective?
           Consider that less weight means there is a smaller force to
            oppose lift
       Stability
           What parts of the glider can help make it more stable?

   Glider Design (cont.)
                                                       More things to think about:
                                                           Center of gravity
                                                               This is the theoretical point where the
                                                                weight of the plane is concentrated
                                                               What will happen if the center of gravity
                                                                is too far forward or too far back?
                                                           Aerodynamics & drag
                                                               How can you make the shape of your
                       From               plane more aerodynamic?
                                                               Which surface produces less friction: a
                                                                smooth, waxed surface or a rough
    Glider Design (cont.)
   One more thing:
       Wing design
           The wing aspect ratio is the ratio of the
            wing’s span to its area

             Wing aspect ratio = (Span of wing)2
                                  Area of wing

           Long, thin wings (high wing aspect ratio)
            are more efficient—they produce less
            drag compared to the lift that they
           Short, stubby wings (low wing aspect
            ratio) are sturdier and more                                    From
           Which design is better in a glider?
Real-Life Applications
   A number of careers involve aircraft design and
    flight, including:
       Engineer (design, testing, materials, and more)
       Pilot
       Astronaut
       Air Traffic Controller

   How Stuff Works:
   NASA Glenn Research Center – Aerodynamics:
   NASA Quest:

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