# Shared Flashcard Set

## Details

Aerodynamics I EO's
EO's for Aero
135
Other
Not Applicable
03/30/2009

## Additional Other Flashcards

Term
 Descrive the relationship between thrust and power.
Definition
 Pr = (Tr * V)/325
Term
 Define thrust required and power required.
Definition
 Thrust required - the amount of thrust required to overcome drag (expressed in pounds). Power required - the amount of power required to produce thrust required.
Term
 Describe how thrust required and power required varies with velocity.
Definition
 Power required is dependent on thrust and velocity.
Term
 State the location of L/Dmax on the thrust required and power required curves.
Definition
 Thrust required curve: at bottom of curvePower required curve: to the right of the bottom of cuve
Term
 Define thrust availiable and power availiable.
Definition
 Thrust availiable - the amount of thrust that the airplane"s engines are actually producing at a given throttle setting, density and velocity. Power availiable - the amount of power that the airplane's engines are actually producing at a given throttle setting, density and velocity.
Term
 Describe the effects of throttle setting, velocity, and density on thrust available and power availiable for a turboprop engine.
Definition
 Thrust availiable - max thrust availiable occurs at full throttleas velocity increases thrust availiable decreasesas density decreases, thrust available decreases Power available - max power available occurs at full throttleas velocity increases power will initially increase but then decrease due to a decrease in Thrust availableas density decreases power available decreases
Term
 Define Thrust horsepower, shaft horsepower, and propeller efficiency.
Definition
 THP = proeller outputSHP = engine outputPE = the ability of the propeller to turn engine output into thrust
Term
 State the relationship between thrust horsepower, shaft horsepower, and propeller efficiency.
Definition
 Under ideal conditions, SHP would equal THP, but due to friction in the gearbox and propeller drag.  THP is always less than SHP.  PE is always less than 100 percent.
Term
 State the flat rated shaft horsepower and the Navy limited shaft horsepower of the T-34C PT6A-25 engine.
Definition
 550 SHP(1315 ft/lbs of torque)/425 SHP(1015 ft/lbs of torque)
Term
 Define Thrust excess and power excess
Definition
 thrust excess occurs if thrust available is greater than thrust required at a particular velocity.Te = Ta - Trpower excess occurs if power available is greater than power required and will produce an acceleration, a climb, or both.Pe = Pa - Pr
Term
 State the effects of a thrust excess or a power excess.
Definition
 thrust excess - an acceleration, a climb or both.power excess - an acceleration, a climb or both. (negative thrust/pwr excess will cause a descent or deceleration or both)
Term
 State the conditions necessary to achieve the maximum thrust excess and maximum power excess for a turboprop airplane.
Definition
 Max thrust excess occurs at full throttle setting and at a velocity less than L/Dmax for a turboprop. Max power excess occurs at L/Dmax for a turboprop.
Term
 Describe the effects of changes in weight on thrust required, power required, thrust available and power available.
Definition
 Tr and Pr curves shift up and to the right (They shift to the right b/c more weight = more lift needed = an increase in velocity. they shift up because more velocity = more drag = more thrust needed)  Weight changes have no effect on Ta and Pa as they do not affect the engine.
Term
 Describe the effects of changes in weight on maximum thrust excess and maximum power excess
Definition
 They decrease at every AOA and velocity
Term
 Describe the effects of changes in altitude on thrust required, power required, thrust available, and power available
Definition
 Thrust Required - curve shifts to the rightPower Required - curve shifts up and to the right
Term
 describe the effects of changes in configuration on thrust required, power required, thrust available and power available
Definition
 Lowering landing gear:  does not affect thrust/power availableincreases thrust/power required (curves move up) Lowering flaps: does not affect thrust/power availableincreases thrust/power required (curves move up and to the left)
Term
 describe the effect of changes in altitude on max thrust excess and max power excess and on the airspeeds necessary to achieve max thrust and max power excess
Definition
 They will both decrease (thrust excess decreases because as altitude increases, density decreases and there is therefore less thrust available)(power excess decreases because pwr available decreases and pwr required increases) The airspeed necessary to achieve max thrust and max pwr excess will INCREASE
Term
 Describe the effects of changes in configuration on maximum thrust excess and max power excess, and on the airspeeds necessary to achieve max thrust and max power excess.
Definition
 They will both decrease (because thrust/pwr required increase with landing gear & flaps) The airspeed necessary to achieve max thrust and max power excess will decrease.
Term
 Define scalar quantity
Definition
 a quantity that represents only magnitude(time/temp/volume)
Term
 Define vector quantity
Definition
 a quantity that represents magnitude and direction.(displacement,velocity,acceleration,force)
Term
 Force
Definition
 push or pull exerted on a bodyF = ma
Term
 Mass
Definition
 The quantity of molecular material that comprises an object
Term
 Volume
Definition
 the amount of space occupied by an object
Term
 Density
Definition
 mass per unit volumeD = m/v
Term
 Weight
Definition
 the force with which a mass is attracted toward the center of earth by gravity. 32.174 ft/s^2
Term
 Moment
Definition
 a vector quantity equal to a force times the distance from the point of rotation that is perpendicular to the force. M = F*d
Term
 Work
Definition
 a scalar quantity equal to the force times the distance of displacement.  W = F*s
Term
 Power
Definition
 the rate of doing work or work done per unit time. P = W/t
Term
 Energy
Definition
 a scalar measure of a body's capacity to do work.TE = KE + PE
Term
 Potential Energy
Definition
 The ability of a body to do work because of its position or state of being. PE = mgh
Term
 Kinetic Energy
Definition
 ability of a body to do work because of its motion.KE = 1/2 mv2
Term
 Define total drag, parasite drag and induced drag
Definition
 Drag is the component of the aerodynamic force that is paralell to and acts in the same direction as the relative wind. Total drag is the sum of parasite and induced drag.Dt = Dp + Di Parasite drag is any drag not associated with the production of lift: friction, form, interference. Induced drag is the part of total drag associated with the production of lift.
Term
 Three types of parasite drag
Definition
 form, friction, interference
Term
 State the cause of each major type of parasite drag
Definition
 Form - (aka pressure/profile drag) caused by airflow separation from a surface and the low pressure wake that is created by that separation. Friction - drag arising from friction forces at the surface of an aircraft due to the viscosity of the air. Interference - caused by the mixing of streamlines between components
Term
 State the aircraft design features that reduce each major type of parasite drag
Definition
 Form - streamline surfaces Friction - smoothing surfaces by cleaning,waxing, painting, or polishing aircraft surfaces parasite - proper fairing and filleting
Term
 Describe the effects in changes in density, velocity and equivalent parasite area (f) on parasite drag, using the parasite drag equation
Definition
 Dp = ½ρV2f = qf they are all directly proportional to drag so as any of them increase parasite drag increases and vise versa. if you double speed you will create 4 times as much drag. also, for density to increase altitude must decrease so altitude and parasite drag are inversely proportional.
Term
 describe the effects of upwash and downwash on the life generated by an infinite wing
Definition
 for an infinite wing the upwash exactly equals the downwash resulting no net change in lift. upwash and downwash exist any time an airfoil is producing lift.
Term
 Describe the effects of upwash and downwash on the life generated by a finite wing
Definition
 for a finite wing some of the wind flows spanwise around the wingtips and then combines with the chordwise flow which doubles the downwash (wingtip vortices)
Term
 State the cause of induced drag
Definition
 caused by parallel component of lift and acts in the same direction as drag and tends to retard the forward motion of the airplane; varies inversely with velocity and directly with angle of attack.
Term
 state the aircraft design features that reduce induced drag
Definition
 Install devices that impede spanwise airflow going around wingtips:  wingletswingtip tanksmissile rails
Term
 Describe the effects of changes in lift, weight, density, and velocity on induced drag using the induced drag equation
Definition
 DI = KL2/ρV2b2 = KW2/ρV2b2 Lift and Weight vary directly with induced drag so if they increase, induced drag will increase and vise versa. density and velocity vary inversely with induced drag so as they increase induced drag will decrease and vise versa. wingspan also varies inversely with induced drag. as AOA increases so does induced drag
Term
 Describe the effects of changes in velocity on total drag
Definition
 an increase in velocity will increase parasite drag and decrease induced drag and vise versa.
Term
 define and state the purpose of the lift to drag ratio
Definition
 it determines the efficiency of an airfoil.  a high lift to drag ratio indicates a more efficient airfoil.
Term
 state the importance of L/DMax
Definition
 produces the minimum total dragparasite drag and induced drag are equalproduces the greatest lift to drag ratiomost efficient AOAany movement away from L/Dmax will increasee drag
Term
 State the advantages and disadvantages of tapering the wings of the T-34
Definition
 Advantages: they reduce weight, improve stiffness and reduce wigtip vortices Disadvantages:  Even stall progression of tapered wings (ailerons are at wingtip and plane will loose lateral control)
Term
 state the purpose of wing tailoring
Definition
 the purpose of wing tailoring is to create a root to tip stall progression and give the pilot some stall warning while ensuring that the ailerons remain effective up to a complete stall
Term
 describe geometric twist
Definition
 a decrease in angle of incidence from wing root to wing tip
Term
 describe aerodynamic twist
Definition
 a decrease in camber from wing root to wing tip
Term
 state the types of wing tailoring used on the T-34
Definition
 aerodynamic twist and geometric twist (3.1 °)
Term
 pitch attitude
Definition
 the angle between the horizon and the airplane's longitudinal axis
Term
 flight path
Definition
 the path the airplane's center of gravity follows as it moves through an air mass
Term
 relative wind
Definition
 airflow the airplane experiences as it moves through the air; equal in magnitude and opposite in direction to flight path
Term
 angle of attack
Definition
 the angle between the relative wind and the chordline of an airfoil
Term
 mean camber line
Definition
 a line drawn halfway between the upper and lower surfaces of the wing
Term
 positive camber
Definition
 when the mean camber line is above the chordline
Term
 negative camber
Definition
 when the mean camber line is below the chordline
Term
 symmetric airfoil
Definition
 when the mean camber line is coincident with the chordline
Term
 aerodynamic center
Definition
 the point along the chordline where all changes in the aerodynamic force takes place (located 23-27 percent of the length of the chord from the leading edge)
Term
 airfoil thickness
Definition
 height of the airfoil profile. the point of max thickness corresponds to the aerodynamic center
Term
 spanwise flow
Definition
 airflow that travels along the span of the wing parallel to the leading edge; does not produce lift
Term
 chordwise flow
Definition
 air flowing at right angles to the leading edge of an airfoil.  the only airflow that produces lift
Term
 aerodynamic force
Definition
 force that is the result of pressure and friction distribution over an airfoil and can be resolved into 2 components: lift and drag
Term
 lift
Definition
 the component of the aerodynamic force acting perpendicular to the relative wind
Term
 Drag
Definition
 the component of the aerodynamic force that acts parallel to and in the same direction as the relative wind
Term
 describe the effects on dynamic pressure, static pressure and the aerodynamic force as air flows around a cambered airfoil and a symmetirc airfoil
Definition
 symmetric airfoil - at zero AOA there will be identical velocity increases and static pressure decreases on the upper and lower surfaces and therefore there will be zero net lift. cambered airfoil - even at zero AOA the airflow above the wing will be faster than that below the wing and the static pressure on the top of the wing will therefore be lower than under the wing creating a pressure differential and therefore producing a lifting force.
Term
 Describe the effects of changes in AOA on the pressure distribution and AF of cambered and symmetric airfoils
Definition
 incresasing the AOA on any airfoil causes the area of the streamtube above the wing to decrease and produces a greater velocity increase above the wing than below which will increase the pressure differential which will increase the magnitude of the aerodynamic force
Term
 Describe the effects of changes in density, velocity, surface area, camber, and angle of attack on lift
Definition
 increase in density = increase in liftincrease in velocity = increase in liftincrease in surface area = increase in liftincreaes in camber = increase in liftincrease in AOA = increase in lift(up to ClmaxAOA)
Term
 List the factors affecting lift that the pilot can directly control
Definition
 ??? AOA???velocity???camber???SA??density?? need to ask instructor becaues we have gotten several different answers
Term
 compare and contrast the coefficients of lift generated by cambered and symmetric aifoils
Definition
 At zero AOA: a positive cambered airfoil has a positive CLa negative cambered airfoil has a negative CLa symmetric airfoil has a CL = 0
Term
 define boundary layer
Definition
 that layer of airflow over a surface that demonstrates local airflow retardation due to viscosity; it grows in thickness as it moves aft over the surace of an airfoil
Term
 list and describe the types of boundary layer airflow
Definition
 Laminar & turbulent laminar - air moves smoothly along in steamlines, produces very little friction but is easily separated from the surface turbulent - the flow is disorganized and irregular, produces higher riction drag but adheres to the upper surface of the airfoil delaying boundary layer separation
Term
 state the cause and effect of boundary layer separation
Definition
 the adverse pressure gradient impedes the flow of the boundary layer which does not have sufficient Kinetic energy to overcome the adverse pressure gradient and the BL will separate from the surface
Term
 define stall and state the cause of the stall
Definition
 a condition of flight where an increase in AOA will result in a decrease in CL the only cause of a stall is excessive AOA beyond CLmax
Term
 Define and state the importance of CLmax and CLmax AOA
Definition
 CLmax is the peak coefficient of lift and any increase in AOA beyond CLmax AOA produces a decrease in CL CLmax AOA is known as the "stalling angle of attack" or critical AOA and the region beyond CLmax AOA is the stall region.  Regardless of the flight conditions or airspeed, the wing will always stall beyond the same AOA
Term
 State the procedure for stall recovery
Definition
 the only action necessary for stall recovery is to decrease the AOA below CLmax AOA   but the steps in stall recovery are: (max, relax,level)
Term
 List common methods of stall warning and identify those used for the T-34
Definition
 Common methods:  AOA indicatorsrudder pedal shakersstick shakershornsbuzzerswarning lightselectronic voices T-34: AOA indicator AOA indexerrudder pedal shakers
Term
 state the stalling AOA of the T-34C
Definition
 between 29.0 and 29.5 units(reguardless of airspeed, nose attitude, weight or altitude)
Term
 define stall speed (Vs)
Definition
 the minimum true airspeed required to maintain level flight at CLmax AOA
Term
 Describe the effects of weight, altitude and thrust on true and indicated stall speed, using the appropriate equations
Definition
 Vs = √[2W/(ρSCLmax )] IASs = √[2W/(ρ0SCLmax )] if weight increases, stall speed increasesif altitude increases, stall speed (TAS) increases but indicated stall speed (IAS) does not change since ρ0 is constant **power on stall speed is less than power off stall speed because at high pitch attitudes part of the weight of the airplane is being supported by the vertical component of the thrust vector.
Term
 State the purpose of high lift devices
Definition
 to increase lift at low airspeeds and to reduce takeoff and landing speeds by reducing stall speed
Term
 state the effect of boundary layer devices on the coefficient of lift, stalling AOA and stall speed
Definition
 increases coefficient of liftincreases stalling AOAdecreases stall speed
Term
 state the effect of flaps on the coefficient of lift, stalling AOA, and stall speed
Definition
 increases the coefficient of liftdecreases stalling AOAdecreases stall speed
Term
 describe different types of boundary layer devices
Definition
 fixed slots and slats fixed slots - gaps located at the leading edge of a wing that allow air to flow from below the wing to the upper surface slats - moveable leading edge sections used to form automatic slots
Term
 describe the operation of boundary layer control devices
Definition
 fixed slots - high pressure air from the leading edge stagnation point is directed through the slot, which acts as a nozzle converting the static pressure into dynamic pressure.  the high kinetic energy air leaving the nozzle increases the energy of the boundary layer and delays separation slats - when slats are deployed it opens a slot
Term
 describe different types of flaps
Definition
 plain - hinged portion of trailing edge forced down into air stream to increase cambersplit - a plate deflected from lower sfc...creates drag due to turbulent air btwn wind and deflected sfcslotted - moves away from wing to open a slot for Boundary layer controlFowler - used on large airplanes, moves down to increase camber and aft to increase wing area and opens a slot for Boundary layer controlLeading edge - change wing camber at leading edge of airfoil
Term
 state the stall pattern exhibited by rectangular,elliptical, moderate taper, high taper and swept wing platforms
Definition
 rectangular - root stall tendencyelliptical - even stall progressionmoderate taper - even stall progressionhigh taper - tip stall tendencyswept wing - tip stall tendency
Term
 Define steady airflow, streamline and streamtube
Definition
 steady airflow - exists if at every point in the airflow static pressure, temp, density and velocity remain constant over time.  A particle of air follows the same path as the preceeding particle. streamline - the path that air particles follow in steady airflow streamtube - a collection of streamlines.  it is a closed system.
Term
 Describe the relationship between airflow velocity and cross sectional area within a streamtube using the continuity equation
Definition
 A1V1 = A2V2 if the cross sectional area decreases on one side of the equation then the velocity must increase on the same side so both sides remain equal; velocity and area in a streamtube are inversely related.
Term
 list the components of the pitot static system
Definition
 pitot tubestatic pressure sourceblack box
Term
 state the pressure sensed by each component of the pitot static system
Definition
 pitot tube - total pressure static pressure port - ambient static pressure black box - calculates the dynamic pressure and displays it on a pressure gauge inside the cockput...the IAS gauge
Term
 define mach number and critical mach number
Definition
 mach number is the ratio of the airplane's true airspeed to the local speed of soundM = TAS/LSOS Critical Mach number is when supersonic airflow exists somewhere on the airplane, usually the upper surface of wing
Term
 describe the effects of altitude on Mach number and critical Mach number
Definition
 an increase in altitude will increase mach number because the local speed of sound decreases and also the increase in altitude results in a decrease in temperature which also reduces the speed of sound
Term
 taper ratio
Definition
 the ratio of the tip chord to the root chord
Term
 sweep angle
Definition
 the angle between the lateral axis and a line drawn 25% aft of the leading edge
Term
 aspect ratio
Definition
 ratio of the wingspan to the average chord.   glider = high aspect ratiofighter = low aspect ratio AR = b/c
Term
Definition
 ratio of an airplane's weight to the surface area of its wings WL = W/S (there tends to be an inverse ratio btwn AR and WL)
Term
 Angle of Incidence
Definition
 the angle between the airplane's longitudinal axis and the chordline of its wing.
Term
 Dihedral angle
Definition
 the angle btwn the spanwise inclination of the wing and the lateral axis.(the upward slope of the wing as viewed from the front)
Term
 Describe and state the advantages of the semi-monocoque fuselage construction
Definition
 a modified version of monocoque having skin, transverse frame members and stringers which all share in stress loads and may be readily repaired if damaged.
Term
 describe full cantilever wing construction
Definition
 all bracing is internal
Term
 Define, compare and contrast equilibrium and trimmed flight
Definition
 equilibrium  is the absence of acceleration, either linear or angular.  equilibrium flight exists when the sum of all forces and moments around the center of gravity is zero and trimmed flight is when the sum of all moments around the center of gravity is equal to zero. if you are in equilibrium flight you are in trimmed flight but the reverse is not true.
Term
 Define static pressure
Definition
 the pressure each air particle exerts on another.
Term
 Air density
Definition
 mass of air particles per unit volume. density decreases with an increase in altitude
Term
 temperature
Definition
 a measure of the average kinetic energy of the air particles
Term
 average lapse rate
Definition
 temp decrease linearly with an increase in altitude at a rate of 2 degrees celsius (3.57F) per 1000 ft 36000 ft.
Term
 Humidity
Definition
 the amount of water vapor in the air
Term
 viscosity
Definition
 a measure of the air's resistance to flow and shearing. air viscosity increases with an increase in temperature
Term
 state the relationship between humidity and density
Definition
 as humidity increases air density decreases
Term
 state the relationship between temperature and viscosity
Definition
 as temperature increases, air viscosity increases
Term
 state the relationship between temperature and local speed of sound
Definition
 as temperature increases local speed of sound increases
Term
 State the pressure, temperature, lapse rate, and air density at sea level in the standarrd atmosphere using both metric and english units of measurement
Definition
 English             MetricPressure           29.92 in Hg    1013.25 mb         Temperature                59F                    15C    Average lapse rate   2C/1000ft      3.57F/1000ft   Air Density       .0024 slugs/ft^3     1.225 g/l      LSOS                            661.7kts         340.4m/s
Term
 State Newton's 3 laws of motion
Definition
 1st - a body at rest tends to remain at rest and a body in motion tends to remain in motion in a straight line at a constant velocity unless acted upon by some unbalanced force 2nd - F = ma, an unbalanced force acting on a body produces an acceleration in the direction of the force that is directly proportional to the force and inversely proportional to the mass of the body: a = F/m 3rd - kaw if interaction - ex: thrust produced in a jet engine
Term
 identify examples of newton's 3 laws of motion
Definition
 1st - an airplane in strait and level flight at constant velocity: thrust = drag and lift = weight, when plane is in equilibrium 2nd - when an airplane's thrust is greater than its drag (in level flight) excess thrust will accelerate the airplane until drag increases to equal thrust. 3rd - thrust produced in a jet engine
Term
 state the relationships btwn altitude and temp, pressure, air density, and LSOS within the standard atmosphere
Definition
 as altitude inceases, temperature decreases, pressure decreases, and LSOS decreases
Term
 state the relationship btwn pressure, temp, density using the general gas law
Definition
 they are all directly related to pressure, if holding pressure constant and increasing temperature, density must decrease and vise versa P = row RT
Term
 define compare and contrast aircraft and airplane
Definition
 aircraft = any device intended to be used for flight in the air.   airplane = a heavier than air, fixed wing aircraft driven by an engine and supported by the dynamic reaction of airflow over its wings
Term
 List and describe the 3 major control surfaces of an airplane
Definition
 ailerons - control rollrudder - controls yawelevator - controls pitch
Term
 list and define the 5 major components of an airplane
Definition
 fuselage - basic structure of an airplane engine - provides thrust neccessary for flight wing - produce lift empennage - provides greatest stabilizing influence of all components of an airplane.  Consists of aft part of fuselage, vertical and horizontal stabilizer landing gear -  used for ground taxi and to absorb shock of takeoff and landings
Term
 components of airplane reference system
Definition
 longitudinal axis - passes from nose to tail of acftlateral axis - passes from wingtip to wingtipvertical axis - passes vertically through the CG
Term
 List and define the otions that occur around teh airplane CG
Definition
 roll/lateral control - movement of lateral axis around longitudinal axis pitch/longitudinal control - movement of longitudinal axis around lateral axis yaw/directional control - movement of longitudinal axis around vertical axis
Term
 wingspan
Definition
 the length from wingtip to wingtip
Term
 chordline
Definition
 an infinitely long strait line that passes through the leading and trainling edges of an airfoil
Term
 chord
Definition
 a measure of the distance along the chordline from the leading to trailing edgge. a measure of the width of the wing
Term
 tip chord
Definition
 the chord at the wing tip
Term
 root chord
Definition
 the chord at the wing centerline
Term
 average chord
Definition
 average of every chord from wingroot to wingtip
Term
 wing area
Definition
 the surface area of the wing from wingtip to wingtip, the wingspan times the average chord: S = bc
Term
 Taper
Definition
 a reduction in chord from wingroot to wingtip
Term
 indicated airspeed
Definition
 the instrument indication for the dynamic pressure the airplane is creating during flight
Term
 calibrated airspeed
Definition
 indicated airspeed corrected for instrument/installation error
Term
 equivalent airspeed
Definition
 calibrated airspeed corrected for compressibility error.  EAS = TAS at sea level on a standard day that produces the same dynamic pressure as the actual flight condition
Term
 true airspeed
Definition
 the actual speed of the aircraft through the air mass.  it is EAS corrected for density
Term
 ground speed
Definition
 TAS corrected for wind. a measure of an airplanes speed over the ground.
Term
 describe the relationship btwn total pressure, static pressure and dynamic pressure within a streamtube using bernouli's equation
Definition
 Pt = Ps + q the pitot tube measures the total pressure, the static port measures static pressure and the blackbox determines the dynamic pressure by subtracting static pressure from total pressure.  so if q increases then ps must decrease for total pressure to remain constant
Term
 describe the relationships btwn weight, lift, velocity and AOA in order to maintain strait and level flight using the lift equation
Definition
 L = W = qSCL = ½ρV2SCL In order to maintain level flight while increasing AOA, velocity must decrease. otherwise lift will be greater than weight and the airplane will climg.  velocity and AOA are inversely related in level flight.
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