NIFE Aerodynamics 2-3-1 Performance Characteristics Flashcards
Define takeoff and landing air speeds in terms of stall speed
Takeoff: 20% above the power-off stall speed
Landing: 30% higher than stall speed
Describe the effects on takeoff performance given variations in weight, altitude, temp, and humidity
(Indicated will always stay the same)
- Weight increase > V increases
- Altitude increase > Density decrease > V increases
- Temp increase > Density decrease > V increases
- Humidity increase> density decrease > V increases
4-H club
High, hot, heavy, humid AND tailwind
Describe the effects on landing performance given variations in weight, altitude, temp, and humidity
- W increase > V increases
- Alt increase > dense decrease > V increase
- Temp increase > dense decrease > V increase
Define maximum angle of climb profile (AOC, gamma sign)
Maximum vertical velocity for a minimum horizontal velocity. Getting over an obstacle.
Define maximum rate of climb profile (ROC)
Flying at max ROC yields a maximum vertical velocity. Used to expedite a climb to an assigned altitude. Max altitude in min amount of time
Define maximum range profile
Max distance traveled over the ground for a given amount of fuel.
Define maximum endurance profile
The max amount of time that an airplane can remain airborne on a given amount of fuel.
Explain the requirements yielding max range in relation to the power curve
Must minimize fuel flow per unit of velocity. Any straight line drawn from the origin represents a constant ratio of fuel flow to velocity. Max range is found at L/Dmax AOA and velocity. Max range is faster than max endurance.
Explain the requirements yielding max endurance in relation to the power curve
Min fuel flow occurs at the bottom of the power curve. Therefore, max endurance is found at a velocity less than L/Dmax, and an AOA greater than L/Dmax AOA for a turboprop
Describe the effect of altitude on max range and max endurance performance
An increase in altitude requires a higher throttle setting due to the lower density. Eventually the temp decrease will make the turbines more efficient > less fuel req’d > max endurance performance increases.
Define maximum glide range profile
Max distance traveled in a glide (fly at L/Dmax AOA)
Define maximum glide endurance profile
Max time airborne in a glide (velocity is less that L/Dmax velocity, and AOA is greater than L/Dmax AOA)
Describe the locations of the region of normal command on the power curve
Velocities above maximum endurance. Velocity and throttle settings for level flight are directly related.
Describe the locations of the region of reverse command on the power curve
Velocities below maximum endurance. Velocity and throttle setting for level flight are inversely related
Explain the relationship between power required and airspeed in the region of normal command
Velocity and throttle settings for level flight are directly related. To fly in equilibrium at a faster speed, more throttle is needed than at a lower airspeed. To fly slower, less throttle is needed.
Explain the relationship between power required and airspeed in the region of reverse command
Velocity and throttle setting for level flight are inversely related. The slower a plane flies, the more throttle will be needed to overcome the extra induced drag due to the higher AOA.
Aerodynamic braking
Accomplished by increasing the parasite drag on the airplane by holding a constant pitch attitude after touchdown and exposing more of the airplane’s surface to the relative wind. Reduces wear on brakes
Mechanical braking
(AKA Frictional/wheel braking) effective only after enough weight is transferred to the wheels and the airplane has slowed sufficiently. Used toward the end of the landing roll.
Crosswinds
Rudder is the primary means of maintaining directional control during t/o and landing. Ailerons must also be placed into the wind to prevent it from rolling.
Define CG range
The safe zone in which the balance point must fall. The extremities of the range are called the forward and aft CG limits. Expressed in inches, along the longitudinal axis from the plane’s datum
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