exam Flashcards
What is the critical angle of attack
an aerodynamic constant for a given airfoil in a given configuration
Steady State Flight
Sum of the forces forward = sum fo the forces rearward
sum fo the forces up = sum of the forces down
how does lift work
results both from pressure difference (Bernoulli) and deflection of air (Newtonian)
thus, lift results form a variable interaction between these processes, whcih are affected by airspeed, angle of attack, and wing geometry
Low Camber and thin wing section
low drag
high speed
Reflex tailing edge wing section
low lift
high drag
Deep Camber and thick wing section
high lift
low speed
Deep Camber and thin wing section
High lift
low speed
Four forces on the aircraft
lift - perpendicular to relative wind
weight - acts through CG towards center of earth
thrust - usually acts to counteract drag
drag - acts rearward parallel to relative wind
Relationship between the speed of sound and temperature
49.1 times the square root of (Temp in F +460)
why does the speed of sound change with temperature
energy of air molecules
warmer weather more active
more energy
as pressure waves go through they have more energy to go through and transfer/change - cold the air molecules want to stick together not transfer - making speed of sound slower
Movement of shockwaves
caused by very slight changes iin air flow direction. This is caused by very small airplane pieces
large changes in direction and pressure of air caused by large, blunt aircraft components. Strong shock waves equate high drag
effects on aircraft when exceeding design speeds
structural failure - don’t know how the aircraft will respond
Swept wing characteristics
an increase in sweep increases Mcrit but aft sweep increases span-wise flow and at slow speed or high alpha flight, there is a stronger tendency for tip stalls which can be extremely dangerous
Critical Mach number
aircraft speed where free stream somewhere on airframe attains supersonic flow
Parameters that define upset recovery
Pitch attitude greater than 25 degrees up
pitch attitude greater than 10 degrees nose down
bank angle greater than 45 degrees or
within the above parameters, but flying at airspeeds inappropriate for the condition
Conditions that lead to upset recovery
wake turbulence
environment
system anomalies induced
pilot induced
a combination of causes
winds hear
icing-alltupes
Upset Recovery fix
recognize and confirm the developing situation
first actions should be correct and timely
use the primary flight instrument
the attitude direction indicator should be used as a primary reference