Complete Solutions
/. State the requirements for an airplane to be in equilibrium - Answer-✅Sum of
forces/moments around the center of gravity are equal to 0
/.State the requirements for trimmed flight - Answer-✅All moments around the center of
gravity are equal to 0
/.Describe the relationship between humidity and density - Answer-✅They are inversely
related. Humidity encompasses water molecules in the air which equally displace the air
particles and have less mass than air particles. As Humidity increases air density
decreases.
/.Define Steady Airflow - Answer-✅Airflow at which the Pressure, Velocity,
Temperature, and Density remain constant over time. The velocity and direction are the
same at every point but change when going from A to B.
/.Define Streamline - Answer-✅The path that airflow particles flow in when in steady
airflow. In Steady airflow particles do not cross streamlines.
/.Define Streamtube - Answer-✅A collection of many streamlines
/.Explain the continuity equation given cross sectional area and velocity - Answer-
✅A1V1=A2V2. Area and Velocity are inversely related. EX: Water hose. The energy
going in must equal the energy going out. If at one point the cross sectional area is less,
the velocity on the same section must increase to equal out.
/.Explain Bernoulli's Equation - Answer-✅Pt=Ps+Pd. Pd=Q. Q=1/2*rho*V^2. In a closed
system, Ps and Pd are inversely related.
/.Define Wingspan - Answer-✅Distance from wingtip to wingtip
/.Define Wing Area - Answer-✅Surface area of the wing. Average Chord multiplied by
Wingspan
/.Define Chordwise Airflow - Answer-✅Runs perpendicular to the leading edge.
Associated with lift.
, /.Define Spanwise Airflow - Answer-✅Runs parallel to leading edge. Not associated
with lift.
/.Define Pitch Attitude - Answer-✅The angle between longitudinal axis and the horizon
/.Define Flight Path - Answer-✅The airplanes path defined by its CG as it moves
through an air mass.
/.Define Relative Wind - Answer-✅The airflow that the airplane experiences as it moves
through the air. Equal in magnitude and opposite in direction.
/.Define Angle of Incidence - Answer-✅The angle between the longitudinal axis and the
chordline
/.Define center of gravity - Answer-✅Point at which all weight is concentrated, where all
forces/moments are measured.
/.Define the aerodynamic center - Answer-✅Point along the chordline where all
changes in aerodynamic forces take place. On subsonic airfoil, point is located 1/4
length of the chord from the trailing edge. Also located at the point of max thickness or
where we have the most positive camber.
/.Describe the pressure distribution around an airfoil, given changes in angle of attack
and camber. - Answer-✅Lift is due to an imbalance in pressure distributions over the
top and bottom surfaces. High AoA means more pressure underneath wing & less
velocity and above the wing less pressure and more velocity.
/.Lift Equation - Answer-✅L=Q*S*Cl which is (1/2*Rho*V^2) (Surface Area) (Coefficient
of Lift)
/.CL encompasses - Answer-✅CARVAC - Compressibility, Aspect Ratio, Viscosity,
Angle of Attack, Camber
/.Pilot can't control - Answer-✅Viscosity and Compressibility
/.Pilot Can Control - Answer-✅Angle of Attack and Camber (Shape of the airfoil, Flaps)
/.Define ClMax - Answer-✅- As angle of attack increases, the coefficient of lift reaches
its max value, ClMax. The greatest Cl that can be produced.
- Two aspects of Cl that can be controlled are AoA and camber
-Velocity and Angle of attack are inversely related in level flight.
/.Describe the Relationship between ClMax and AoA - Answer-✅- ClMAX AoA is the
called the most effective AoA