Aerodynamics Flashcards
Forces Acting on an Aircraft
- Lift
- Weight
- Thrust
- Drag
Angle of Attack
AOA
The angle at which the airfoil meets the oncoming airflow. The angle measured between the resultant relative wind and chord line.
How is lift generated, and what specific principles are involved?
Lift is generated when an object changes the direction of flow of a fluid or when the fluid is forced to move by the object passing through it.
1) Bernoulli’s Principle/ Venturi Flow
2) Newton’s 3rd law of motion
What kinds of drag exist?
- Induced
- Profile
- Parasite
- Total
Induced Drag
Induced drag is generated by the airflow circulation around the rotor blade as it creates lift.
Profile Drag
Profile drag develops from the frictional resistance of the blades passing through the air.
Parasite Drag
Parasite drag is caused by non-lifting components as the aircraft moves through the air, and it increases with airspeed.
Total drag
Total drag is the sum of the three drag forces
Blade Span
the length of the rotor blade from center of rotation to the tip of the blade
Chord Line
a straight line intersecting leading and trailing edges of the airfoil
Chord
the length of the chord line from the leading edge to the trailing edge
Mean camber line
a line drawn halfway between the upper and lower surfaces of the airfoil (follows the shape of the airfoil)
Leading Edge
the front edge of an airfoil
Flightpath Velocity
the speed and direction of the airfoil passing through the air
Relative wind
the airflow relative to an airfoil and is created by movement of an airfoil through the air.