Descrive the relationship between thrust and power.

Pr = (Tr * V)/325

Thrust required - the amount of thrust required to overcome drag (expressed in pounds).

Power required - the amount of power required to produce thrust required.

Thrust required curve: at bottom of curve

Power required curve: to the right of the bottom of cuve

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.

Thrust availiable -

max thrust availiable occurs at full throttle

as velocity increases thrust availiable decreases

as density decreases, thrust available decreases

Power available -

max power available occurs at full throttle

as velocity increases power will initially increase but then decrease due to a decrease in Thrust available

as density decreases power available decreases

THP = proeller output

SHP = engine output

PE = the ability of the propeller to turn engine output into thrust

thrust excess occurs if thrust available is greater than thrust required at a particular velocity.

Te = Ta - Tr

power excess occurs if power available is greater than power required and will produce an acceleration, a climb, or both.

Pe = Pa - Pr

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)

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.

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.

Thrust Required - curve shifts to the right

Power Required - curve shifts up and to the right

Lowering landing gear:

does not affect thrust/power available

increases thrust/power required (curves move up)

Lowering flaps:

does not affect thrust/power available

increases thrust/power required (curves move up and to the left)

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

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.

a quantity that represents only magnitude

(time/temp/volume)

a quantity that represents magnitude and direction.

(displacement,velocity,acceleration,force)

push or pull exerted on a body

F = ma

mass per unit volume

D = m/v

the rate of doing work or work done per unit time.

P = W/t

a scalar measure of a body's capacity to do work.

TE = KE + PE

The ability of a body to do work because of its position or state of being.

PE = mgh

Kinetic Energy

ability of a body to do work because of its motion.

KE = 1/2 mv²

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.

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

Form - streamline surfaces

Friction - smoothing surfaces by cleaning,waxing, painting, or polishing aircraft surfaces

parasite - proper fairing and filleting

D_p = 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.

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.

Install devices that impede spanwise airflow going around wingtips:

winglets

wingtip tanks

missile rails

D_I = KL²/ρV²b^{2 =} 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

produces the minimum total drag

parasite drag and induced drag are equal

produces the greatest lift to drag ratio

most efficient AOA

any movement away from L/Dmax will increasee drag

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)

airflow the airplane experiences as it moves through the air; equal in magnitude and opposite in direction to flight path

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.

increase in density = increase in lift

increase in velocity = increase in lift

increase in surface area = increase in lift

increaes in camber = increase in lift

increase in AOA = increase in lift(up to ClmaxAOA)

??? AOA???velocity???camber???SA??density??

need to ask instructor becaues we have gotten several different answers

At zero AOA:

a positive cambered airfoil has a positive C_L

a negative cambered airfoil has a negative C_L

a symmetric airfoil has a C_L = 0

define boundary layer

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

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

a condition of flight where an increase in AOA will result in a decrease in C_L

the only cause of a stall is excessive AOA beyond C_Lmax

C_Lmax is the peak coefficient of lift and any increase in AOA beyond C_Lmax AOA produces a decrease in C_L

C_Lmax AOA is known as the "stalling angle of attack" or critical AOA and the region beyond C_Lmax AOA is the stall region.  Regardless of the flight conditions or airspeed, the wing will always stall beyond the same AOA

the only action necessary for stall recovery is to decrease the AOA below C_Lmax AOA

but the steps in stall recovery are: (max, relax,level)

Common methods:

AOA indicators

rudder pedal shakers

stick shakers

horns

buzzers

warning lights

electronic voices

T-34:

AOA indicator 

AOA indexer

rudder pedal shakers

between 29.0 and 29.5 units

(reguardless of airspeed, nose attitude, weight or altitude)

V_s = √[2W/(ρSC_Lmax )] IAS_s = √[2W/(ρ₀SCLmax )]

if weight increases, stall speed increases

if 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.

increases coefficient of lift

increases stalling AOA

decreases stall speed

increases the coefficient of lift

decreases stalling AOA

decreases stall speed

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

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

plain - hinged portion of trailing edge forced down into air stream to increase camber

split - a plate deflected from lower sfc...creates drag due to turbulent air btwn wind and deflected sfc

slotted - moves away from wing to open a slot for Boundary layer control

Fowler - used on large airplanes, moves down to increase camber and aft to increase wing area and opens a slot for Boundary layer control

Leading edge - change wing camber at leading edge of airfoil

rectangular - root stall tendency

elliptical - even stall progression

moderate taper - even stall progression

high taper - tip stall tendency

swept wing - tip stall tendency

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. 

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.

pitot tube

static pressure source

black box

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

mach number is the ratio of the airplane's true airspeed to the local speed of sound

M = TAS/LSOS

Critical Mach number is when supersonic airflow exists somewhere on the airplane, usually the upper surface of wing

the angle between the lateral axis and a line drawn 25% aft of the leading edge

ratio of the wingspan to the average chord. 

glider = high aspect ratio

fighter = low aspect ratio

AR = b/c

wing loading

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)

the angle btwn the spanwise inclination of the wing and the lateral axis.

(the upward slope of the wing as viewed from the front)

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.

           English             Metric

Pressure           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

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

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

they are all directly related to pressure, if holding pressure constant and increasing temperature, density must decrease and vise versa

P = row RT

define compare and contrast aircraft and airplane

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

ailerons - control roll

rudder - controls yaw

elevator - controls pitch

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

longitudinal axis - passes from nose to tail of acft

lateral axis - passes from wingtip to wingtip

vertical axis - passes vertically through the CG

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

the length from wingtip to wingtip

TAS corrected for wind. a measure of an airplanes speed over the ground.

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

L = W = qSC_L = ½ρV²SC_L

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.