Forces of Flight Flashcards
Relationship between W, L in a climb?
W>L
Excess thrust must exist for the climb
Relationship between T,D in a descent?
T
What are the 2 things the pilot can control to change lift?
AOA and Velocity
Lift equation?
L = CAS^2 x AOA
How does lowering the flaps affect the C_L vs Alpha curve?
Lowering the flaps increases the camber of the 38s symmetric wing, increasing the amount of lift at a given AOA, raising the C_L curve
What is the definition of an aerodynamic stall?
When the wing is not longer able to produce lift at a given AOA. On the C-L vs Alpha graph, this occurs at the peak of the curve.
How do you identify C_L Max on a T_R graph?
It is the left most point
How does weight affect the level-flight stall speed?
Weight increases stall airspeed
How does flap setting affect the level-flight stall speed?
Lowering the flap decreases stall airspeed
How does bank angle affect the level-flight stall speed?
Increases stall speed
How is parasite drag affected by an increase in CAS?
Parasite drag increases with an increase in CAS
How is parasite drag affected by configuration?
Extending the gear or speed break increase the parasite drag, raising its drag line on the Drag vs CAS graph
How is induced drag affected by an increase in CAS?
Induced drag decreases with an increase in CAS
How is induced drag affected by an increase in AOA?
Induced drag increases with an increase in AOA
How is induced drag affected by an increase in weght?
Induced drag increases with an increase in wegiht
How is induced drag affected by an increase in bank angle?
Induced drag is increased with an increased bank angle
Briefly describe how total drag changes with airspeed?
Your airspeed (CAS) is initially low. At these low airspeeds, induced drag (drag created by the production of lift) is the dominant drag force. As speed increases, induced drag affects decrease until Lift/Drag Max. As airspeed increases past this point, parasitic drag becomes the dominant drag force and increases as CAS increases
What is L/D Max in the 38?
230 KCAS + 1 KCAS per 100 lbs of fuel
How does an increase in weight affect the total drag vs. CAS (level flight) graph?
An increase in weight raises the curve and moves it to the right
How does an increase in bank angle affect the total drag vs. CAS (level flight) graph?
An increase in bank angle raises the curve and moves it to the right
How does lowering your gear (changing configuration) affect the total drag vs. CAS (level flight) graph?
Changing your configuration (dropping the gear) raises the curve and moves it to the left. It decreases L/D Max (L/D Max occurs at a lower airspeed)
Define thrust available:
Thrust available is the amount of thrust the engines can produce based of multiple parameters including:
- A given throttle setting
- Velocity
- Density
Define thrust required:
The amount of thrust needed to maintain level unaccelerated flight
How is thrust available affected by an increase in RPM?
An increase in RPM increases the thrust available
How is thrust available affected by an increase in ambient temperature?
Thrust available decreases
How is thrust available affected by an increase in pressure altitude?
Thrust available decreases
On a thrust vs. CAS graph, where is the region of normal command?
It occurs after L/D Max
On a thrust vs. CAS graph, where is the region of reverse command?
It occurs before L/D Max
Where is the stall airspeed located on this graph?
The left most point
What is the lock point and where is it on this graph?
Minimum continous level-flight airspeed, ID by the yellow dot on the far left of the graph. This is at 200 knots
