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Aero I
Enabling Objectives
163
Aviation
04/10/2016

Term
 Define scalar
Definition
 a quantity that represents only magnitude. Expressed with a single number and units.
Term
 Define vector
Definition
 a quantity that represents magnitude and direction.
Term
 Define mass
Definition
 the amount of molecular material of which an object is comprised
Term
 Define volume
Definition
 The amount of space an object occupies
Term
 Define density
Definition
 Mass per unit volume. ρ = m / v
Term
 Define force
Definition
 a push or pull exerted on an object. F = m*a
Term
 Define weight
Definition
 the force exerted on an object by gravity directed toward the center of the earth
Term
 Define moment
Definition
 A force applied to a lever, at some distance perpendicular to an axis or fulcrum that tends to produce a rotation around that axis
Term
 Define work
Definition
 done when a force acts on a body and moves it. W = F * s (s = displacement)
Term
 Define power
Definition
 The rate of doing work or work done per unit time. P = W / t
Term
 Define energy
Definition
 The ability of a body to do work due to its motion or its position/state of being. TE = KE + PE
Term
 Define potential energy
Definition
 The ability of a body to do work due to its position or state of being. PE = weight * height = m*g*h
Term
 Define kinetic energy
Definition
 The ability of a body to do work due to its motion. KE = 1/2 * m*V^2
Term
 Explain Newton's Law of Equilibrium
Definition
 First law: a body at rest tends to stay at rest and a body in motion tends to stay in motion in a straight line at a constant velocity unless acted upon by some unbalanced force. Principle is called inertia
Term
 State requirements for airplane to be in equilibrium flight
Definition
 The sum of all forces and all moments around the airplane's center of gravity must equal zero.
Term
 State requirements for an airplane to be in trimmed flight
Definition
 The sum of all moments around the airplane's center of gravity must equal zero
Term
 Explain Newton's Law of Acceleration
Definition
 A force applied to a mass tends to produce an acceleration in the direction of the force, directly proportional to the magnitude of the force and inversely proportional to the mass of the object. a = F / m
Term
 Explain Newton's Law of Interaction
Definition
 For every action there is an equal and opposite reaction; the forces of two bodies on each other are always equal and are directed in opposite directions. Demonstrated when rearward force from a propeller's propwash causes an aircraft to thrust forward at an equal amount of force.
Term
 Define static pressure
Definition
 The pressure particles of air exert on adjacent bodies. Ambient static pressure is equal to the weight of a column of air on a given area
Term
 Define air density
Definition
 The total mass of air particles per unit volume
Term
 Define temperature
Definition
 A measure of the average random kinetic energy of air particles
Term
 Define lapse rate
Definition
 The rate at which air temperature decreases linearly as altitude changes. Average lapse rate for standard conditions are 2°C or 3.57°F per 1000' altitude increase
Term
 Define humidity
Definition
 The amount of water vapor in the air
Term
 Describe relationship between humidity and air density
Definition
 As humidity increases, air density decreases, as water molecules push away air particles
Term
 Define viscosity
Definition
 The resistance of a fluid to flow or shearing
Term
 Describe relationship between temperature and viscosity
Definition
 For air, as temperature increases, viscosity increases. In liquids, as temperature increases, viscosity decreases.
Term
 Define local speed of sound
Definition
 The speed that a sound wave travels through air for a given set of conditions
Term
 Describe the relationship between temperature and local speed of sound
Definition
 As temperature increases, LSoS increases due to the fact that the air particles are more excited and can execute the wave motion faster.
Term
 State the values for standard sea level pressure
Definition
 29.92 inHg or 1013.25 mbar
Term
 State the values for standard temperature
Definition
 15°C or 59°F
Term
 State the values for standard average lapse rate
Definition
 2°C or 3.57°F per 1,000 feet altitude increase
Term
 State the values for standard ρ0 (air density)
Definition
 0.0024 slugs/ft^3 or 1.225 g/L
Term
 State the values for standard local speed of sound
Definition
 661.7 knots or 340.4 m/s
Term
 Describe the general gas law
Definition
 P = ρ*R*T where P is pressure, ρ is density, R is the gas constant and T is temperature
Term
 Explain Bernoulli's equation
Definition
 H = Ps + q. H = total pressure, Ps = static pressure and q = dynamic pressure = 1/2 * ρ * V^2
Term
Definition
 For any given point over time in a streamline, there is a constant velocity, pressure, temperature and density
Term
 Define streamline
Definition
Term
 Define streamtube
Definition
Term
 Explain continuity equation
Definition
 A1 * V1 = A2 * V2. Disregarding compressibility, amount of mass flowing through one end of a streamtube must match the other end, regardless of area.
Term
 Define indicated altitude
Definition
 The altitude shown on an altimeter (static pressure corrected for Kollsman window setting)
Term
 Define AGL altitude
Definition
 The actual height above ground
Term
 Define MSL altitude
Definition
 The actual height over a standard reference level, the average sea level value
Term
 Define pressure altitude
Definition
 The height over a standard datum plane, where pressure would be equal to 29.92 (IA corrected for instrument error and density)
Term
 Define density altitude
Definition
 Pressure altitude corrected for non-standard temperature deviation. Not used as an actual height, but as a measure of aircraft performance. High Da = low performance, low air density
Term
 Describe the Pitot-Static system
Definition
 Pitot tube which measures ram air pressure at v=0 so total pressure, and static port on the side which measures static pressure.
Term
 Define indicated airspeed
Definition
 the airspeed shown on an airspeed indicator (measured from pitot-static system)
Term
 Define calibrated airspeed
Definition
 Indicated airspeed corrected for installation/instrument error
Term
 Define equivalent airspeed
Definition
 True airspeed at sea level on a standard day; calibrated airspeed corrected for compressibility error
Term
 Define true airspeed
Definition
 The actual speed through the air; equivalent airspeed corrected for air density
Term
 Define groundspeed
Definition
 The actual speed over ground. TAS corrected for headwind/tailwind component
Term
 Describe factors affecting indicated airspeed
Definition
 Literally just dynamic pressure converted to speed. Could have installation or position errors affecting accuracy. Also an instrument blockage could render this useless
Term
 Describe factors affecting calibrated airspeed
Definition
 Compressibility of air approaching speed of sound can cause this to be inaccurate
Term
 Describe factors affecting calibrated airspeed
Definition
 air density variation from standard conditions (temperature and pressure) can affect this value; it is based on the reference plane.
Term
 Describe factors affecting true airspeed
Definition
 a headwind/tailwind could be pushing or pulling you
Term
 Define an aircraft
Definition
 any device used to ascend and move through air. Includes dirigibles, lighter than air, airplanes, rotorcraft, etc.
Term
 Define an airplane
Definition
 Heavier than air, engine-propelled, creates lift by dynamic reaction of air moving over its surfaces
Term
 List the five components of an airplane
Definition
 Fuselage, wings, engine, empennage, landing gear
Term
 Describe the fuselage
Definition
 The main structure of the airplane; all other components are attached to this. Carries persons and cargo. Can be manufactured using truss, semi-monocoque or monocoque construction
Term
 Describe the wings
Definition
 airfoil that forces air up and over it. Attached to the fuselage, may be one of three types of camber, and contains ailerons and may have flaps/slats/slots to change camber and airflow. May be semi-cantilever or full cantilever construction.
Term
 Describe the engine
Definition
 Either jet engine or prop engine; attached to the fuselage. Generates thrust that is used to push the airplane through the air
Term
 Describe the empennage
Definition
 Consists of a horizontal and vertical stabilizer. Rudder attached to vertical stabilizer, elevator attached to horizontal stabilizer. Might contain trim aid devices. Attached to the fuselage.
Term
 Describe landing gear
Definition
 Absorbs the shock and allows for ground roll on takeoff/landing. Also used for taxiing/ground operations. Nose wheel may be steerable with the rudder pedals. May be conventional (tailwheel) or tricycle (nose wheel) configuration and may be fixed or retractable.
Term
 State the advantages of semi-monocoque fuselage construction
Definition
 Balance between weight and strength; easier to fix than monocoque and lighter than truss type.
Term
 Describe full cantilever wing construction
Definition
 All bracing and support is inside the wings; attached to fuselage only at wing root.
Term
 Describe the airplane three-axis reference system
Definition
 Vertical axis goes through CG; Longitudinal axis goes from nose to tail of airplane; Lateral axis extends wingtip-to-wingtip.
Term
 Define chord line
Definition
 an infinite line extending from leading edge to trailing edge of a wing
Term
 Define chord
Definition
 a measurement at one point of the wing along the chord line from leading edge to trailing edge
Term
 Define root chord
Definition
 The length of the chord at the base of the wing
Term
 Define tip chord
Definition
 the length of the cord measured at the wingtip
Term
 Define average chord
Definition
 the mean of all chords along the airplane's chord line. used for calculating surface area, ratios, etc.
Term
 Define mean camber line
Definition
 a line drawn equidistant from the top and bottom surfaces of the wing from leading edge to trailing edge.
Term
 Define symmetric airfoil
Definition
 An airfoil that produces zero net lift at a zero angle of attack. MCL = chord line
Term
 Define positive camber
Definition
 An airfoil that produces positive net lift at zero angle of attack. MCL > chord line
Term
 Define negative camber
Definition
 An airfoil that produces negative net lift at zero angle of attack. MCL < chord line
Term
 Define spanwise flow
Definition
 airflow parallel to the leading edge; generally from wing root toward wingtip. Does not generate lift.
Term
 Define chordwise flow
Definition
 airflow perpendicular to the leading edge, generates lift
Term
 Define pitch attitude
Definition
 The angle between the longitudinal axis and the horizon
Term
 Define flight path
Definition
 the actual path that the CG experiences while moving through the air
Term
 Define relative wind
Definition
 The airflow the airplane experiences as it moves through the air. Equal and opposite in magnitude/direction to flight path
Term
 Define angle of attack
Definition
 The angle between chord line and relative wind
Term
 Define angle of incidence
Definition
 The angle between chord line and longitudinal axis of airplane
Term
 Define dihedral angle
Definition
 Angle between lateral axis and the upward inclination of the wings
Term
 Define wingspan
Definition
 the length from wingtip to wingtip
Term
 Define wing area
Definition
 The total area of the wing including the portion over/in the fuselage. Wingspan * average chord
Term
Definition
 Ratio of weight to surface area WL = W / S
Term
 Define taper ratio
Definition
 the ratio of chord of airfoil from root to tip: ƛ = cT / cR
Term
 Define sweep angle
Definition
 angle between line drawn 25% from leading edge of wing to lateral axis
Term
 Define aspect ratio
Definition
 ratio of wingspan to average chord AR = b / c
Term
 Define center of gravity
Definition
 Point at which all weight is experienced, considered to be concentrated
Term
 Define aerodynamic center
Definition
 Point at which all changes in aerodynamic force appear to act from
Term
 Describe motions that occur around airplane CG
Definition
Term
 Explain aerodynamic relationship of four primary forces of equilibrium flight
Definition
 Lift tends to counter weight but can also add to drag. Thrust generally counters drag but can also counter weight when climbing. To have equilibrium flight, the forces must cancel out and also not create any net moment.
Term
 Describe how the four primary aerodynamic forces affect each other
Definition
 Drag counters thrust. Weight generally is opposed to lift.
Term
 State pressure distribution around an airfoil
Definition
 Static pressure is lower above an airfoil when creating lift, and opposite for negative lift. Increasing AoA increases pressure differential between lower and upper surfaces until reaching CLMax AoA.
Term
 Define lift component of aerodynamic force
Definition
 Always perpendicular to the relative wind. Can be directly counter to weight as in level equilibrium flight, but often has a rearward component.
Term
 Describe how factors in the lift equation affect lift production
Definition
 L = 1/2 * ρ * V^2 * S CL, and CL is affected by compressibility, aspect ratio, viscosity, Angle of Attack, and camber
Term
 List factors affecting coefficient of lift that pilot can directly control
Definition
 Only angle of attack and camber
Term
 Define drag component of aerodynamic force
Definition
 Always parallel to relative wind and in same direction. D = 1/2 * ρ * V^2 *S * CD. Consists of parasite and induced drag components.
Term
 Defuse parasite drag
Definition
 Drag not associated with the production of lift. Includes form, friction and interference drag
Term
 Define form drag
Definition
 Caused by the separation of air and turbulent low-pressure wake behind the object.
Term
 Define friction drag
Definition
 Caused by rough surfaces causing turbulent/adhering motion of wind, delayed separation
Term
 Define interference drag
Definition
 Caused by airflow around two different parts intersecting
Term
 Describe measures to reduce form drag
Definition
 Streamlining causes less wake behind the surface
Term
 Describe measures to reduce friction drag
Definition
 painting, sanding, overall making surface smoother
Term
 Describe measures to reduce interference drag
Definition
 Proper filleting and fairing ensures smooth meeting of airflow and less interference drag.
Term
 State effects of upwash and downwash on infinite wing
Definition
 upwash moves lift component forward, increases AoA. Downwash is equal and opposite and moves lift component rearward, reducing AoA.
Term
 State effects of upwash and downwash on finite wing
Definition
 same as infinite, but downwash is about twice as strong. This causes lift component to be slightly rearward due to span wise flow over the wingtip contributing to excess downwash moving AoA to be smaller.
Term
 Define induced drag
Definition
 rearward component of lift in the direction of relative wind
Term
 Define cause of induced drag on a finite wing
Definition
 spanwise flow over the wingtip contributes to increased downwash. This reduces the AoA and thus pushes lift component rearward.
Term
 Describe factors affecting induced drag
Definition
 Di = k*L^2 (or W^2) / ρ * V^2 * b^2b = wingspan, L = lift, W = weight, k is a constant
Term
 State when an airplane will enter ground effect
Definition
 Within 1 wingspan of the ground
Term
 Describe effects of AoA changes on CL and CD
Definition
 increasing AoA increases both CL and CD until reaching CLMax, then it only increases CD
Term
 Explain lift to drag ratio using lift and drag equations
Definition
 L and D equations cancel out to be CL/CD. This ratio defines the efficiency of the airplane with relation to velocity and angle of attack
Term
 Explain importance of L/DMax
Definition
 Most efficient speed/AoA to fly airplane
Term
 Define total drag
Definition
 Induced plus parasite drag. All forces that act in same direction as relative wind.
Term
 Describe effects of changes in velocity on total drag
Definition
 Increased velocity increases total drag by squared factor
Term
 Define thrust required
Definition
 The amount of thrust required to fly the airplane at a given airspeed/AoA
Term
 Define thrust available
Definition
 The amount of thrust at given throttle, density for a given airspeed/AoA
Term
 Define power required
Definition
 The amount of power required to fly airplane at an airspeed/AoA
Term
 Define power available
Definition
 Power at given throttle/PCL and density for given airspeed/AoA
Term
 Describe effects of throttle setting on thrust available and power available
Definition
 For a plane, TA increases with throttle increase. So does PA
Term
 Describe effects of velocity on TA and PA
Definition
 For prop, TA decreases as AS increases. for Jets it remains constant
Term
 Describe effects of density on TA and PA
Definition
 both TA and PA increase with increased density.
Term
 Define shaft horsepower
Definition
 Actual power produced by engine to turn shaft
Term
 Define propeller efficiency
Definition
 The percentage of power converted into thrust by a prop engine.
Term
 State max rated shaft HP in T-6B
Definition
 1100 HP
Term
 Explain how prop efficiency affects thrust horsepower
Definition
 THP = Pe * SHP
Term
 Describe power required in terms of thrust required
Definition
 PR = TR * V / 325
Term
 State location of L/DMax on TR curves
Definition
 At the lowest point of the TR curve
Term
 State location of L/DMax on PR curves
Definition
 To the right of the bottom; at the same velocity and AoA as on the TR curve
Term
 Describe how thrust required varies with velocity
Definition
 It decreases to point of L/DMax and then increases
Term
 Describe how power required varies with velocity
Definition
 It decreases as induced drag decreases but then increases with increase of velocity and increase of parasite drag
Term
 Define excess thrust
Definition
 the difference between thrust available and thrust required for a given velocity, throttle setting and density
Term
 Define excess power
Definition
 difference between power available and power required for given velocity, throttle setting and air density
Term
 Describe effects of excess thrust and excess power
Definition
 Will cause airplane to either accelerate or climb depending on AoA
Term
 Describe effects of changes in weight on thrust required
Definition
 moves curve up and to right; more TR and velocity required
Term
 Describe effects of changes in weight on power required
Definition
 moves curve up and to right
Term
 Describe effects of changes in weight on excess thrust
Definition
 decreases Te at all locations
Term
 Describe effects of changes in weight on excess power
Definition
 decreases Pe at all locations
Term
 Describe effects of changes in altitude on thrust required
Definition
 moves curve right
Term
 describe effects of changes in altitude on power required
Definition
 moves curve right and up
Term
 describe effects of changes in altitude on thrust excess
Definition
 decreases for prop airplane, not for jet
Term
 Describe effects of changes in altitude on power excess
Definition
 decreases power excess for every setting
Term
 Describe effects of configuration changes on thrust required
Definition
 moves curve up for gear, up and left for flaps, up and right for weight
Term
 Describe effects of configuration changes on power required
Definition
 moves curve up for gear, up and left for flaps, up and right for weight
Term
 Describe effects of configuration changes on thrust excess
Definition
 decrease excess thrust in general
Term
 Describe effects of configuration changes on power excess
Definition
 decreases power excess
Term
 Describe aerodynamic effects of raising or lowering flaps
Definition
 lowering increases lift but also increases drag. allows you to fly at a slower airspeed for a given AoA. changes wing to be positively cambered
Term
 Describe aerodynamic effects of raising and lowering landing gear
Definition
 Increases parasitic drag. Requires more thrust for given AoA/Airspeed
Term
 Explain aerodynamic effects of ailerons on aircraft
Definition
 Ailerons move in opposite direction from each other. Causes more positive lift to be generated on one side and produces roll.
Term
 Explain aerodynamic effects of elevator on aircraft
Definition
 Causes air to either push up or down the tail and affect the nose opposite.
Term
 Explain aerodynamic effects of rudder on aircraft
Definition
 creates pressure differential on sides of rudder and produces yawing motion. used for coordinated flight.
Term
 Describe how trim tab system holds an airplane in trimmed flight
Definition
 move it opposite of the direction the control surface moves to produce a moment on that control surface. Will tend to hold it in place.
Term
 Define aerodynamic balancing
Definition
 Used to keep control pressures associated with higher velocities within reasonable limits. shaping airfoil in order to balance aerodynamic forces
Term
 Define mass balancing
Definition
 Affecting stability of control surfaces using weights/design to move CG
Term
 State methods for aerodynamic balancing employed on T-6B
Definition
 Shielded horn in elevator, Overhang in ailerons, shielded horn in rudder
Term
 State methods for mass balancing employed on T-6B
Definition
 weighted overhang
Term
 List three types of control systems
Definition
 Conventional, power-boosted and full-power (fly-by-wire)
Term
 State characteristics of conventional control system
Definition
 motion of stick/rudder pedals directly move control surfaces. provides direct feedback with aerodynamic forces/changes
Term
 State characteristics of power-boosted control system
Definition
 Hydraulic, pneumatic or electric power boost. Some feedback, not as much as conventional
Term
 State characteristics of fly-by-wire control system
Definition
 Full-power systems provide no direct feedback and is completely controlled by electric systems. Can use artificial feedback.
Term
 State how trim tabs can be used to generate artificial feel on a control surface
Definition
 Servo trim tabs make it easier, moving opposite. Anti-servo trim tabs move with, making it more difficult.
Term
 Describe purpose of bobweights and downsprings
Definition
 downsprings make it more difficult to pull stick aft at slow speeds, and bobweights make it more difficult in maneuvering flight. for artificial feel.
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