Definitions Flashcards
Left Turning Tendency
A/c may veer to left during takeoff because application of power
Vy
Best rate of climb
74 knots
Highest altitude at less time
Just below the 10 degree pitch mark
Vx
Best angle of climb
62 knots
Highest altitude at less distance
Four fundamentals of flight
Climbs
Descents
Turns
Straight & level flight
Straight & level flight
Not turning,holding altitude
Cowling, angle of wing tip to horizon, attitude indicator
Pitch nose to horizon
Four forces of flight
Lift
Drag
Weight
Thrust
Thrust = drag & lift = weight: straight unaccelerated flight
Bernoulli’s principle
As air is forced over the top of the wing, it speeds up, & pressure decreases
Airfoil
Shape of wing
Camber
Curve of airfoil
Chord line
Imaginary line connecting leading and trailing edge in an airfoil
Relative wind
Opposite direction of flight path
Leading edge and trailing edge
Leading edge is the beginning of an airfoil
Trailing edge is the end of an airfoil
Angle of attack
AOA
Angle between relative wind and wing chord line
If AOA is too great, it’ll disrupt the production of lift
Lift reduced, drag increased = stall (15-20 degrees)
Three axes of rotation
Vertical axis
Lateral axis
Longitudinal axis
Vertical axis
Through a/c
Rotates about to the L/R
Rudder controls Yaw
Lateral axis
Wing to wing
Rotation up/down
Elevator controls pitch
Longitudinal axis
Nose to tail
Rotation side/side
Ailerons controls roll
Three types of turns
Shallow
Medium
Steep
Shallow
20 degrees or less
Aileron & rudder must be held
Medium
20 to 45 degrees
Little aileron & rudder
Steep
45 degrees or more
Opposite aileron & rudder needed
Over banking tendency: bc o/s wing flies a bigger arc & travels greater distance than inside wing
Bigger arc = more distance = faster = more lift
Centripetal force
Any force towards the center of the turn (horizontal lift)
Centrifugal force
A force acting outward on a body moving around a center , arising from the body’s inertia
Bank turn
Vertical component opposing weight
Horizontal component that pulls a/c into turn
Turn = lower vertical lift, a/c descend
- to prevent, increase AOA
Load Factor
The total lift the wings produce, divided by weight of a/c (measured in Gs)
Ratio of increased lift to actual a/c weight
Increased LF = Increased angle of bank, flying in turbulence, pulling out of a dive
- cause increase stall speed (reach critical AOA faster) (bank angles more than 30 degrees)
Stability
The tendency to return to straight and level flight
- if it gets disturbed, it’ll cycle through a few oscillations
What is the max load factor for normal category?
3.8 Positive Gs
What is the max load factor for utility category?
4.4 positive Gs
What is the minimum load factor for normal category?
1.52 negative Gs
What is the minimum load factor for utility category?
1.76 negative Gs
What is the relation between load factor and the aircraft?
If loaded and operated accordingly than the airframe can withstand a load factor of up to 3.8 times the a/c max gross weight w/o structural damage
What causes excessive airframe stress?
High airspeed
high load factor
What do you do when experncing turbulence?
Reduce airspeed to maneuvering speed, VA
Maneuvering Speed
Max speed you can apply full deflection of any one control and not cause structural damage
SINGLE deflection of a SINGLE CONTROL
Full control deflection
Moving any control surface (ailerons, rudders, elevator) until you hit the stops
What are the pros and cons of full control deflection
- cause a/c to exceed critical AOA and stall before exceeding load factor limits
- damage may be caused by deflection of more than one control surface at once or repeated control deflections
- used when flying in turbulence or performing maneuvers that could impose increased load factor
What is the relationships between VA & Weight?
More Weight = Increased VA
Less Weight = Decreased VA
What is the suggested VA in a 172SP?
105 KTS @2550lbs
98 KTS @2200lbs
90 KTS @1900
When is it best to have mixture leaned?
Cruise flight or above 3000ft MSL
When is it best to have mixture richened?
Maneuvers below 3000ft MSL
What do you avoid to prevent rapidly cooling the engine? Why?
Extended descents at idle b/c it stresses the cylinder head and could cause it to crack
If transitioning from a descent/climb to straight & level, what is the best vertical climb rate
About a 10% vertical climb rate level off
What are the types of drag?
Induced drag
Parasite drag
Induced Drag
Caused by the production of lift & varies inversely w/ speed
Airspeed goes up then induced drag goes down
Airspeed goes down then induced drag goes up
Parasite Drag
Caused by the a/c moving through air
Varies directly w/ speed
When airspeed increases then parasite drag increases
When airspeed decreases then parasite drag decreases
What is total drag?
Induced drag + parasite drag
Define best glide speed
Where total drag is the least and is located at the lowest point on the total drag curve and highest ratio of lift
What is the relationship between glide speed, distance, and weight?
think seven
- an a/c will glide the greatest distance when power is off (no wind conditions) if flown at a specific airspeed for the total weight
- reduce glide speed by 5% for every 10% below max gross weight
- less weight = slower glide speed
- more weight = faster glide speed
- 9 to 1: every 1000ft you can glide 9000ft (1.5 miles) with no wind
- less glide distance if flaps used or flying faster/slower then best glide speed
- glide speed changes w/ weight (distance does not)
What are the four causes of a/c left turning tendencies?
- torq
- propeller factor
- slipstream effect
- gyroscopic pression
Torq
Newtons 3rd law: for every action there is an opposite & equal reaction
Ex: propeller rotates to right, a/c will roll/yaw to the left
Propeller Factor
P factor or Asymmetrical Thrust
One side of propeller produces more thrust hence yaws to the left, results with high AOA
Slipstream Effect
- when air is pulled in by the propeller is rotated and sent backwards
- strikes vertical stabilizer and rudder on left side (tail)
- yaws to left, rolls to rights about longitudinal axis affecting vertical surfaces above longitudinal axis
Aerodynamic Compensations at cruise speed
- engine slightly points to the right
- trailing edge of vertical stabilizer ( or itself ) may be canted to the right
- left wing greater AOA
Relationship between rudders, power, and speed
High power & Low speed = Right Rudder (climb & slow flight)
Low Power & High speed = Left Rudder ( descent w/ power)
Gyroscopic Pression
Deflection of spinning rotor
- force applied to change axis of rotation (90 degrees in direction of rotation where applied)
- causes to change pitch attitude
- Nose down: effective forward force at top of propeller, 90 degrees to right, pushes nose to right
- Nose up: effective forward force at bottom of propeller,90 degrees to left, pushes nose to left
When is left turning tendency most pronounced
When a/c is flying at low airspeed with engine at high power setting
How to control left turning tendencies
Right rudder: high power & low airspeed
Left rudder: low power & high airspeed
- when you feel like your body is pushed to the right/left, put right/left rudder (INERTIA)
When to keep right rudder
While throttle is pushed forward
T/O
Off ground to compensate for loss of steering control
Climbing
Ground Effect
When flying within one wingspan to ground
Causes & Restrictions of Ground Effect
Causes:
- changes airflow around wind: less drag, more lift, fly @slower speed, float
- less airflow to top of the wing, creates a horizontal whirlpool of air called a vortex within the wake of an aircraft and wingtip vortices (wake turbulence) streaming from the wingtips
Restrictions:
- vertical component of airflow around wing alters upwash, downwash and wing tip vortices
- can lift off at airspeed too slow (less lift = more drag) & possibility of settling back to runway or increasing distances to clear an obstacle
- may overshoot / extra floating distance
Longitudinal stability
Pitch Stability
Inherently stable about the lateral axis (wingtip to wingtip)
Positive Static Stability
The initial tendency of nose to come back up (or to its original position)
Positive Dynamic Stability
The tendency over time of the dampening oscillations to get smaller
YOU NEED POSITIVE STATIC STABILITY TO HAVE DYNAMIC
Neutral Static Stability
A/c stays in displaced position
Negative Static Stability
A/c continues in same direction as it’s being displaced
How is longitudinal stability determined?
By the CG in relation to the location of the CL
What is the relations between CG, CL, and stability?
- The further forward the CG is from the CL, it causes more downward force on the tail hence more stability
- The closer the CG is to the CL, it reduces the downward force on the tail, hence les stability
- If CG is too far aft (rearward): negatively stable when disturbed, stall recovery becomes difficult/impossible
- If CG is too far forward: a/c will be difficult to maneuver & rotating during t/o may be impossible bc may not be able to raise nose from runway
When will CG move?
When any of the weight distributions changes
- fuel weights, pax weights, baggage loading
