NIFE AERO EXAM QUESTIONS
AND ANSWERS VERIFIED 100%
CORRECT
Turbulent flow - Answer-Disorganized/irregular, large amounts of friction drag, delayed
separation (adheres to surface)
Describe boundary layer separation in regards to adverse pressure gradient - Answer-
air wants to move from high Ps areas to low (max thickness point on airfoil), as it travels
past the max thickness point it encounters an adverse pressure gradient. If there's not
enough boundary layer kinetic energy (q) to overcome pressure gradient it will begin to
separate (airflow aft of separation point reverses)
*adverse pressure gradient strongest at high lift conditions and high AoAs (separation
point moves toward leading edge)
Stall - Answer-CLmaxAOA is exceeded, resulting in decrease of CL
Explain difference between true and indicated stall speed - Answer-True stall speed:
increases with altitude (ρ decreases and higher V needed for lift)
* Vs = sqrt((2W)/(ρSCLmax))
Indicated stall speed: no change with altitude as it uses ρ0 (sea level density) in the
equation
Explain the effects of gross weight, altitude, and flaps given the stall speed equation -
Answer-Vs = sqrt((2W)/(ρSCLmax))
Weight: directly proportional, increase in W results in increase in Vs
Altitude: directly proportional, as altitude increases density decreases and Vs increases
Density: inversely proportional, as density decreases Vs increases
Flaps: when extended increases CLmax, which decreases Vs
Explain the difference between speeds with respect to power on and power off stalls -
Answer-Power on stall: there exists a vertical component of thrust (lower Vs compared
to power off)
Power off stall: no vertical component of thrust, meaning higher Vs
What are the factors necessary for an airplane to spin? - Answer-Uncoordinated stall;
consists of both stalling moment and yawing moment
One wing is more stalled than the other
, Describe the relationships between the wings during a spin - Answer-inside wing is
more stalled and has a higher AoA, more drag, and lower CL
Spin recovery - Answer-PARE
1. Power - Idle
2. Ailerons - Neutral
3. Rudder - Full opposite
4. Elevator - Forward to break stall
Once spin stops return to level flight
Takeoff and landing airspeeds in terms of stall speed? - Answer-Takeoff: 20% greater
than Vs (1.2 times Vs equation)
Landing: 30% greater than Vs (1.3 times Vs equation)
where Vs = sqrt((2W)/(ρSCLmax))
Describe the effects in takeoff and landing performance, given variations in weight,
altitude, temperature, and humidity - Answer-4 "H" Club: High, Hot, Humid, Heavy
-> all of these increase the minimum takeoff speed and minimum takeoff distance
-> also increase minimum landing speed and minimum landing distance
*overall: decrease in takeoff/landing performance as these factors increase
Max angle of climb - Answer-Vx : max altitude in minimum DISTANCE (obstacle
clearance)
Max rate of climb - Answer-Vy: max climb rate in minimum TIME
Max range profile - Answer-max DISTANCE traveled for given amount of fuel
- occurs at L/Dmax, most efficient AoA, DT minimum
Max endurance profile - Answer-max TIME airborne for given amount of fuel
- bottom of power curve, Pmin minimum fuel flow required
Requirements yielding max range and max endurance in relation to the power curve? -
Answer-Max range: L/Dmax, higher velocity than max endurance
Max endurance: Pmin, where least amount of fuel is burned, lower velocity but higher
AoA
Describe the effect of altitude on max range and max endurance performance - Answer-
Higher altitude results in better engine performance due to decreased inlet temps to the
engine
-> Max endurance increases as this decreases the amount of fuel flow required.
-> Max range increases because the plane can fly at faster TAS without burning as
much fuel
AND ANSWERS VERIFIED 100%
CORRECT
Turbulent flow - Answer-Disorganized/irregular, large amounts of friction drag, delayed
separation (adheres to surface)
Describe boundary layer separation in regards to adverse pressure gradient - Answer-
air wants to move from high Ps areas to low (max thickness point on airfoil), as it travels
past the max thickness point it encounters an adverse pressure gradient. If there's not
enough boundary layer kinetic energy (q) to overcome pressure gradient it will begin to
separate (airflow aft of separation point reverses)
*adverse pressure gradient strongest at high lift conditions and high AoAs (separation
point moves toward leading edge)
Stall - Answer-CLmaxAOA is exceeded, resulting in decrease of CL
Explain difference between true and indicated stall speed - Answer-True stall speed:
increases with altitude (ρ decreases and higher V needed for lift)
* Vs = sqrt((2W)/(ρSCLmax))
Indicated stall speed: no change with altitude as it uses ρ0 (sea level density) in the
equation
Explain the effects of gross weight, altitude, and flaps given the stall speed equation -
Answer-Vs = sqrt((2W)/(ρSCLmax))
Weight: directly proportional, increase in W results in increase in Vs
Altitude: directly proportional, as altitude increases density decreases and Vs increases
Density: inversely proportional, as density decreases Vs increases
Flaps: when extended increases CLmax, which decreases Vs
Explain the difference between speeds with respect to power on and power off stalls -
Answer-Power on stall: there exists a vertical component of thrust (lower Vs compared
to power off)
Power off stall: no vertical component of thrust, meaning higher Vs
What are the factors necessary for an airplane to spin? - Answer-Uncoordinated stall;
consists of both stalling moment and yawing moment
One wing is more stalled than the other
, Describe the relationships between the wings during a spin - Answer-inside wing is
more stalled and has a higher AoA, more drag, and lower CL
Spin recovery - Answer-PARE
1. Power - Idle
2. Ailerons - Neutral
3. Rudder - Full opposite
4. Elevator - Forward to break stall
Once spin stops return to level flight
Takeoff and landing airspeeds in terms of stall speed? - Answer-Takeoff: 20% greater
than Vs (1.2 times Vs equation)
Landing: 30% greater than Vs (1.3 times Vs equation)
where Vs = sqrt((2W)/(ρSCLmax))
Describe the effects in takeoff and landing performance, given variations in weight,
altitude, temperature, and humidity - Answer-4 "H" Club: High, Hot, Humid, Heavy
-> all of these increase the minimum takeoff speed and minimum takeoff distance
-> also increase minimum landing speed and minimum landing distance
*overall: decrease in takeoff/landing performance as these factors increase
Max angle of climb - Answer-Vx : max altitude in minimum DISTANCE (obstacle
clearance)
Max rate of climb - Answer-Vy: max climb rate in minimum TIME
Max range profile - Answer-max DISTANCE traveled for given amount of fuel
- occurs at L/Dmax, most efficient AoA, DT minimum
Max endurance profile - Answer-max TIME airborne for given amount of fuel
- bottom of power curve, Pmin minimum fuel flow required
Requirements yielding max range and max endurance in relation to the power curve? -
Answer-Max range: L/Dmax, higher velocity than max endurance
Max endurance: Pmin, where least amount of fuel is burned, lower velocity but higher
AoA
Describe the effect of altitude on max range and max endurance performance - Answer-
Higher altitude results in better engine performance due to decreased inlet temps to the
engine
-> Max endurance increases as this decreases the amount of fuel flow required.
-> Max range increases because the plane can fly at faster TAS without burning as
much fuel
