Potpourri
What are the 4 forces of flight?
Thrust, drag, lift, and weight,\
Newton's 3rd law of motion:
Newton's third law of motion states that for every action, there is an equal and opposite reaction
Define relative wind
Airflow flowing parallel and in the exact opposite direction of the aircraft's flight path
Define static stability
The initial tendency of a system to move back toward its original position or state after an outside force or disturbance disrupts it
What are the two types of drag?
Parasite drag and induced drag
What are the three axes of A/C movement?
Pitch around the lateral axis, roll around the longitudinal axis, and yaw around the vertical axis
Newton's 2nd law of Motion:
Newton's second law of motion states that the acceleration of an object depends on the net force acting upon it and the object's mass. F=M*A
Define cord line
An imaginary straight line that connects the front edge of an airfoil to its back edge.
Define dynamic stability
How an object or vehicle behaves over time after a disturbance knocks it out of its balanced state
Which drag type increases fourfold whan A/S airspeed is doubeled?
Parasite drag increases as an aircraft's airspeed increases.
Define airfoil camber
The asymmetric curvature of an airfoil's surface from its front edge to its back edge
Newton's 1st law of motion:
Newton's first law of motion states that an object will remain at rest or keep moving in a straight line at a constant speed unless an outside unbalanced force acts on it.
Define AoA
The angle formed between the chord line of an airplane's wing and the direction of the relative wind
Longitudinal Stability “Pitching” stability about what aircraft axis?
The lateral axis
What three propeller A/C speed and performance references are associated with L/D Max?
Best glide (Vg), best range (VgR), and best climb rate (Vy)
Define airfoil planform
The outline shape of an aircraft wing or lifting surface when viewed from directly above
Describe Bernoulli's principle
If a fluid speeds up, its pressure drops. If it slows down, its pressure rises.
This concept comes from fluid dynamics and the conservation of energy. When a fluid moves faster, more of its energy goes into speed (kinetic energy), which leaves less energy for pushing outward (static pressure).
Define aspect ratio
Wingspan divided by the (average) chord width
What A/C design features manage Longitudinal Stability about what axis?
Longitudinal stability is managed about the lateral (pitch) axis primarily through the design of the horizontal stabilizer, along with the location of the center of gravity (CG) relative to the center of lift.
What the three types of parasite drag?
Form drag, skin friction drag, and interference drag
What three actions can a pilot take to increase lift?
Increase AoA, increase A/S, change wing configuration (i.e. deploy flaps)
What was Bernoulli's first name and about when did he live?
Bernoulli's first name was Daniel (for the most famous one, Daniel Bernoulli), and he lived from 1700 to 1782.
Define angle of incidence
The fixed, built-in angle between an aircraft's longitudinal axis (from nose to tail) and the chord line of its wing.
What A/C design features manage Lateral Stability about what axis? (four)
Lateral Stability (rolling) about the longitudinal axis is managed by Dihedral wings, sweptback wings, keel effect, and weight distribution
What causes induced drag?
Induced drag happens as a direct result of an airplane wing creating lift. High-pressure air under the wing spills over the tips to the low-pressure area above, creating swirling wingtip vortices. These vortices push the air downward into a downwash that tilts the lift backward, creating a rearward force that opposes flight