Thrust PPL ground lesson 4 stage 1

lift opposes

weight

thrust opposes

drag

minimum flying equipment regulation number

91.205

newton’s third law

equal and opposite reaction

how is lift created

with laminar flow! (smooth airflow over the wings)

thrust

force created by airflow over/under wing

byproduct of lift is

drag

in unaccelerated flight, lift = ____ and thrust = _____

lift = weight, thrust=drag

Angle of attack

angle that the air hits the front part of the wing

laminar flow

smooth/fluid airflow going over and under the wing

explain Bernoulli’s principle as applied to wings

camber (curvature) of wing increases airspeed, creating low pressure on top, and there is high pressure on the bottom due to a lower velocity, due to drag from hitting the wing.

upper camber

curvature of wing

lower camber

flat bottom part of wing

chord line

imaginary line from leading to trailing edge in wing. Creates AoA

explain critical angle of attack

laminar flow over upper angle ceases to exist, usually at 17.5 degrees. Stalls happen here

planform

shape of the wing (rectangle, tapered , sweptback, etc)

aspect ratio of a wing

surface area of wing relative to aircraft, think glider (long, skinny wings) vs piper archer (short, stubby wings)

angle of incidence

angle between chord line of wing compared to longitudinal axis of aircraft (nose to tail line)

yoke controls

ailerons, stabilator, elevator

high-lift device explanation and example

increases lift by increasing camber and changing chord line, thus increasing AoA. Ex. flaps

single slotted flap

we use this! flaps that have a small gap between trialing edge of wing and flap. The slot allows some air to go over the topside of the flap. Very aerodynamic

lift is created by Bernoulli’s principle because ___pressure on the bottom side of the wing is chasing the ____pressure on the top side

high, low

slotted-fowler flap

a flap on a rolly track, with a slot for aerodynamics. Used by airliners

load factor

ratio of load supported by wings vs. actual force of gravity (ex. 1G, 2Gs)

propeller function

generate thrust with pressure differentia of blades and its angle of attack

3 forms of parasite drag

form

interference

skin friction

induced drag is a byproduct of ____

lift

example of induced drag

wingtip vortices

wingtips/winglets at the end of airliners are advantageous because they reduce _____ and thus drag

wingtip vortices

wingtip vortices increase

downwash (turbulent, dirty air)

total drag is ___ + _____

parasite and induced

induced drag and speed relationship

inverse

parasite drag and speed relationship

direct

ground effect

cushion of air from wingtip vortices, felt within half a wingspan of wings

static stability

initial tendency of aircraft to return to equilibrium

dynamic stability

tendency to return to equilibrium overtime

positive, negative, neutral STATIC stability

positive—holds new altitude

neutral—no change, just continues

negative—gets more extreme (ex. high goes way higher)

postitive, negative, neutral DYNAMIC stability

positive—returns to pre-disturbance levels

neutral—maintains new disturbance equilibrium

negative—exacerbates disturbance, gets extreme

maneuverability

allows you maneuver and withstand result of stress (ex. from steep turns)

controllability

capability of an airplane to respond to your control inputs

longitudinal stability

ability of an aircraft to return to its pitch

center of lift is ______(in front of/behind) center of gravity in steady flight

behind

lateral stability

ability of an aircraft to resist roll

vertical stability

aircraft’s ability to resist yawing

if you turn right, your ____(left/right) aileron goes up

right

when you pitch down, stabilator at the back of the plane is facing (up/down)

down

longitudinal stability is controlled

latterally (with horizontal stabilator, which creates negative lift and tail down force)

lateral stability is controlled

longitudinally

center of lift is also known as the

center of pressure

CG range

limits between forward most and aft most limits. Outside the limits = no control

RFASLS

Range goes down with forward CG (the rest alternates)

Fuel burn

Airspeed

Stall recovery

Landing flare

Stability

airlines prefer (aft/forward) CG because there is less _____

aft, fuel burn

sideslip

diagonal relative wind makes aircraft move diagonally, even if you think you’re moving forward (like a crab). Fix it with rudder on the same side of the relative wind

dihedral

the slight lowering v shape of the wings coming in towards the fuselage, promotes lateral stability

sweptback wings aid in

directional stability

keel effect

bigger lower fuselage means more directional stability, because it naturally wants to return upright (think about the massive bottom of a boat)

directional stability is achieved via

rudder