Performance & Limitations Flashcards
4 Dynamic Forces
Lift- Upward Acting Force
Gravity (weight)- Downward Acting Force
Thrust- Forward
Drag- Backward
Sum of opposing forces is equal
Steady-state, straight and level unaccelerated flight
Airfoil
Air moving over surface = lift
Wings, horizontal & vertical tail surfaces, propellers
Angle of Incidence
Angle formed by Longitudinal Axis & Chord of wing, fixed and cannot be changed
Relative Wind
Direction of airflow with respect to wing
Wing forward & downward- relative wind backward & upward
Flight path and relative wind always parallel but travel in opposite directions
Angle of attack
Angle wing chord line & direction of relative wind
Bernoullis Principle
Pressure of fluid decreases at points where the speed of fluid increases
High speed flow - low pressure
Low speed - high pressure
Pressure decrease of pressure above wing and increase below produces lift
Factors affecting lift and drag
- Wings (Pilot can change with flaps)
- Airfoil shape (upper curvature of airfoil increased, lift increased- lowering aileron/flap)
- Angle of Attack (increased also increased lift and drag)
- Air Velocity (air passing over wing increased lift and drag)
- Air Density (pressure, temp, and humidity defect density which effects lift & drag- increase, increase, decrease, decrease)
Torque Effect
Newton’s third law of physics- every action there is equal and opposite reaction
Internal engine parts + propeller turn one direction = equal force trying to rotate plane other direction
Torque Effect 4 Factors
- Reaction of Engine & Propeller- propeller to right is making plane roll and bank left
- gyroscopic effect of Propeller- if axis of propeller tilted resulting force exerted 90 degrees ahead in direction of rotation
- Corkscrewing effect of propeller- high speed rotation results in corkscrewing of slip stream moving rearward. Pushes tail to right and yaws plane to left.
- P-factor- high angle of attack downward bite of propeller greater than bite of upward moving blade. Plane yaws left
Centrifugal Force
Equal & Opposite reaction of plane changing direction, acting equal and opposite to horizontal component of lift
Load factor
Actual load supported by wings divided by total weight of plane
Plane can be overloaded and increases stall speed
Maximum load factor
Load factor Max during bank angle after 45-50 degrees
Turbulence could cause increase in angle of attack
Speed- flying below maneuvering plane can stall before load factor excessive, faster can be exceeded by controls or strong turbulence
Maximum Safe (Limit) Load Factors
Normal Airplane
+3.8 to -1.52
Maneuvering Speed
Max speed at which limit load can be imposed without causing structural damage (by gusts or full deflection of control surfaces)
Maneuvering speed increase with increased weight, decreases decreased
LOC-I
Loss of control inflight
Significant deviation of aircraft from intended path
LOC-I accidents occur from uncoordinated flight, equipment malfunctions, pilot complacency, distraction, poor risk management
Stall causation
Increased angle of attack, airflow separated from upper surface of wing