Flight Performance Flashcards
What 2 equations govern the balance of forces in level flight? How do these differ if we also assume steady flight?
T-D=m*dV/dt
L=mg
if steady - T=D
What is the equation relating the stall speed to the maximum value of Cl?
sort(2mg/rhoscl)
Write the ratio of lift to drag in terms of Cl and Cd
L/D=Cl/Cd
What is the condition on the ratio of the lift and drag coefficients to minimise drag?
Cd/Cl is a minimum, Cl/Cd is maximum
What is the condition on the ratio of the lift and drag coefficients to minimise power?
Cd/Cl^3/2 is a minimum
Assuming that Cd=a+bCl^2 that are the expressions for Cl at minimum drag and Cl at minimum power?
Clmd = sqrt(a/b) Clmp=sqrt(3a/b)
Define the safe operating range of an aircraft?
Maximum distance between 2 airfields. taking into account headwind, diversion, stacking, take off, climb and land
Aerodynamically, at what flight condition should an aircraft fly at to maximise its range?
Minimum drag condition
What are the 4 phases an aircraft undertakes during take off?
Ground run
rotation
flare
initial climb
What are the forces acting on the aircraft during the ground run?
Lift Weight Thrust Drag Rolling Friction
What factors affect the take-off distance of an aircraft?
Aircraft weight
Altitude
What is the purpose of the rotation manoeuvre during take off?
Increases angle of attack and coefficient of lift until the lift exceeds the weight and lift off is achieved
What aircraft motion is used to execute a correctly banked turn?
roll
In a correctly banked turn does the bank angle increase or decrease with speed in the turn if the radius of the turn is fixed?
Increase
What is the definition of the load factor?
Lift in the turn/weight of the aircraft
