AME T101 Theory of Flight - Fixed Wing (Part 2) Flashcards
Charts made for the Wing Design of the Aircraft are what?
Airfoil Profiles.
What does C.P. stand for in regards to Airfoil Profiles?
Center of Pressure.
What does C.D. stand for in regards to Airfoil Profiles?
Coefficient of Drag.
What does C.L. stand for in regards to Airfoil Profiles?
Coefficient of Lift.
What does L/D stand for in regards to Airfoil Profiles?
Lift / Drag Ratio.
The ______ the Lift / Drag Ratio the better.
a. Higher
b. Lower
a. Higher
A smaller Center of Pressure does what for an Airfoil?
It stabilizes the Airfoil.
A Higher Aspect Ratio results in more what?
Efficiency
How do you calculate the Aspect Ratio?
Calculation:
Span divided by Average Chord.
What are the two types of drag?
Parasitic and Induced.
Define Parasitic Drag.
Is the result of forcing an object through the air.
What does Parasitic Drag consist of?
Form Drag
Interference Drag
Skin Friction Drag
Define Form Drag.
Is related to both the Size and Shape of the structure.
What is the cause of Skin Friction?
It is caused by the roughness of the Aircraft’s Surface.
How is Skin Friction reduced?
Keeping a Clean Aircraft.
A Smooth Coat of Paint.
Flush Seams and Rivets.
Composite Construction.
How does Interference Drag occur?
Occurs when varied currents of air meet and interact.
How is Interference Drag reduced?
By the use of Fairings and Gap Seals.
Define Induced Drag.
When lift is created, drag is then generated or induced.
What is Induced Drag composed of?
Wingtip Vortices.
Trailing Edge Vortices.
What causes Wingtip Vortices?
Pressure on top of the wing is lower and the pressure below is higher. Higher Pressures attempt to fill in the Lower Pressure.
What are four methods to prevent Wingtip Vortices from forming?
Fences, Winglets, Tip Tanks, and Droop Tips.
How do Fences prevent Wingtip Vortices?
By stopping higher pressure air on the bottom surface from rolling up to the upper surface.
Tip tanks primary focus is to carry fuel…
What is their secondary purpose?
To prevent Vortices.
Describe the function of Droop Tips.
Droop Tips are when wing tips effectively angle downward to prevent Wing Vortices.
What are the three axis of Flight?
Roll
Pitch
Yaw
What are the three control surfaces that allow Roll?
Ailerons
Flight Spoilers
Elevons
What are the four control surfaces that allow for Pitch?
Elevators
Stabilators
Elevons
Ruddervators
What are the two control surfaces that allow for Yaw?
Rudder and Ruddervators
To cause an aircraft to move to the left:
The left aileron will move up while the right would move ______.
a. Up
b. Down
b. Down
To cause an aircraft to move to the right:
The right aileron will go up while the left aileron will move ______.
a. Down
b. Up
a. Down
Define Adverse Yaw.
During the course of a roll more drag is induced.
This increased induced drag results in the plane wanting to either yaw right or left.
How would Adverse Yaw be overcome?
Differential Frise Ailerons are utilized.
What is the advantage of using an Aileron Rudder Inter-Connect?
When turning at certain airspeeds, these inter-connected controls automatically add rudder.
When pitching an Aircraft down, the elevator would move ______.
a. Up
b. Down
b. Down
To pitch an Aircraft up, the elevator would move _____.
a. Down
b. Up
b. Up
How is the elevator controlled?
With the use of a downspring.
What is the Downspring connected to?
The Horizontal Stabilizer.
The primary job of a downspring is to alow control of the elevator.
What is the secondary and in some ways more important job of the downspring?
If the plane is loaded tail heavy, the downspring would automatically control the elevator to keep the aircraft level.
The vertical axis is controlled by what primary control surface?
The Rudder.
To turn the aircraft right, the rudder would have to be moved ______.
a. Left
b. Right
b. Right
To turn the aircraft left, the rudder would have to be moved ______.
a. Left
b. Right
a. Left
Why are primary controls statically balanced?
To prevent fluttering of controls.
How is static balance achieved?
By using lead weights.
How is aerodynamic balancing achieved?
By having th hinge line aft of the leading edge and by extending some of the control surface ahead of the edge.
Secondary controls may also be called what two other names?
Auxiliary Systems or
Trim Systems.
What are Trim Tabs?
Trim Tabs are an adjustable linkage.
What is the purpose of balance tabs?
Balance Tabs assist the pilot in moving the primary control surfaces.
They relieve the force that the pilot must put onto the controls.
How do balance tabs operate?
Balance Tabs work by having the control linkage attached only to the balance tab.
Force put onto the balance tab helps to move the control surface without the need for a lot of effort.
What is the purpose of an Anti-Servo Tab?
These tabs provide feedback for the pilot.
Why is it necessary to provide feedback to the pilot from the control surfaces?
To give the pilot an indication that the control surfaces have full travel.
What is the purpose of Servo Tabs?
Servo Tabs assist the pilot in moving the primary control surfaces.
They accomplish this with the use of hydraulics.
If a hydraulic failure would occur, how would a Servo Tab operate?
Manual input would move the Tab which would move the primary control surface.
What is the purpose of Spring Tabs?
On manual control systems, the pilot would never be able to overcome the forces.
The force of a Spring Tab can be overcome and exerts the appropriate force to move the control surface.
What does it mean for an aircraft to be “Down and Dirty?”
This is when landing gear or another part of teh aircraft are out in the wind when they shouldn’t be.
Name three different loads acting on an aircraft.
G-Forces Changing loads due to turbulence Pressurization Forces Engine Loads (Thrust vs Drag; Torque) Landing Forces
Define aircraft skidding.
The aircraft yaws when turning.
How is aircraft skidding prevented?
Through the use of the Rudder.
What is the calculation for wing loading?
Divide:
Aircraft total Gross Weight
_______BY________
Total Wing Area
What is Newton’s Third Law?
For every action, there is and equal and opposite reaction.
Turning Tendencies for Torque:
For every action, there is an equal and opposite reaction.
What is the aircraft’s action and what is reaction?
The Action: Turning Force of the aircraft’s propeller.
The Reaction: The resulting torque.
In Canada, which way do propeller’s spin?
Clockwise.
What is used to counteract the resulting torque from a propeller?
An Angle of Incidence is used.
What is an Angle of Incidence?
This is an offset to the wings that would make them appear lopsided.
What is the purpose of an Angle of Incidence?
To counteract the resulting torque from the propeller’s spinning.
What does the tail do differently when an angle of incidence is put into the wings?
The tail of plane lifts first when taking off.
Define the effects of Gyroscopic Procession.
A force is put onto a surface and the effect is felt ninety degrees form where is was inflicted.
Example: A wheel spinning on a piece of rope.
Define Propeller Factor
P-Factor
This is when the plane pitches nose up and the descending blades have more lift.
Describe the phenomenon that is Spiraling Slipstream.
The air moving over the surface of the plane spirals.
When Spiraling Slipstream occurs, where does the spiral originate?
From the Propeller’s Blades.
How is Spiraling Slipstream Compensated for?
By installing the vertical stabilizer on an offset angle to the longitudinal axis.
How is aircraft stability defined?
An aircraft in flight naturally returns to a condition of equilibrium after being disturbed.
Define Static Stability.
The initial tendency an aircraft displays after being disturbed.
Define Positive Static Stability.
An aircraft tends to return to equilibrium following a disturbance.
Defin Neutral Static Stability.
An aircraft will not return to equilibrium following a disturbance.
After being disturbed, the instability remains constant.
Define Negative Static Stability.
Once a disturbance has occured, it will continue to get worse; the disturbance continually moves away from equilibrium.
Define Dynamic Stability.
The time required for an aircraft to respond to its static stability following the original attitude.
What are the three different kinds of dynamic stability?
Positive
Neutral
Negative
Define Positive Dynamic Stability.
A Damped Oscillation;
a return to equilibrium occurs.
Define Neutral Dynamic Stability.
Undamped Oscillation;
the disturbance remains constant.
Define Negative Dynamic Stability.
Divergent Oscillation;
there is a continual divergence from equilibrium.
What is another name for Longitudinal Stability?
Horizontal Stability.
What two forces determine if an aircraft has longitudinal stability?
Center of Pressure and
Center of Gravity.
In relation to each other and longitudinal stability….
Where must C.P. and C of G be located?
Center of Pressure must be ahead of the Center of Gravity.
Define Lateral Stability.
This is the stability along the lateral axis.
Define Directional Stability.
This is stability along the vertical axis.
To fly safely, the Center of Gravity should stay within what?
The specified range that the Aircraft is designed for.
Withing the predetermined C of G Range.
If a plane is designed nose heavy, will it stall at:
a. Higher Speed & Lower Angle of Attack.
b. Lower Speed & Higher Angle of Attack.
c. Lower Speed & Lower Angle of Attack
d. Higher Speed & Higher Angle of Attack.
d. Higher Speed & Higher Angle of Attack.
If the Aircraft is loaded to be at either end of the C of G Range, what happens to it’s Stability?
The Aircraft’s Stability lowers dramatically.
What is the purpose of the Horizontal Stabilizer?
The Horizontal Stabilizer provides Longitudinal Stability.
When the elevator is in the “up” position what does the Horizontal Stabilizer provide?
More Control.
The longer the fuselage what does the aicraft naturally have more of?
Natural Stability.
Longer Fuselages provide more of what type of Stability.
Mechanical Stability.
Aircraft Tails that are not T-Tails are greatly effected by what force?
Propeller Wash
T-Tails are further up than their standard Tail counterparts…. why?
So that the Tail is no longer affected by Propeller Wash.
The angle of incidence allows for what kind of take-off?
An almost hands-free take-off.
How does an Angle of Incidence allow for an almost hands-free take-off?
By reducing the need for Primary Controls.
Define the Pendulum Effect.
A tendency to return to the Plane’s Center of Gravity.
What does the term “Dihedral” mean?
These are wings with lower sidelips toward or into the wing.
The plane will slip in one direction, then the other, until it returns to equlibrium.
Define Washout.
The wings have a twisted Angle of Incidence.
The Angle of Incidence is effectively “Washed out.”
Planes that have Washout built into them will have what occur in regards to stalls?
The outboard Angle of Incidence will stall later and the inboard Angle will stall sooner.
How do stall strips work?
Air hits the bottom of the strip as the plane pitches up.
When it hits the the strips bottom, the air burbles up and over the wing.
Causes the wing to stall sooner but allows the pilot to control the ailerons.
Sweptback Wings provide what effect?
As the wing turns, the relative airflow hits one wing more than the other.
This causes the plane to return to straight and level flight.
What does the Vertical Stabilizer promote?
Directional Stability.
The Dorsal Fin was added to create more what?
Vertical Stability.
What is the secondary function of the Dorsal Fin?
Provides more leverage to the vertical stabilizer.
Extra fins may be added to an aircraft for what reason?
To provide additional Directional Stability.
When approaching a stall, how are canards designed to do?
They stall first.
Why are canards designed to stall first?
The aircraft pitches down, and the other two wings, although close to a stall, they will not.
To achieve less lift, what is installed onto an aircraft?
Spoilers
How do spoilers work?
Drag is created which slows the aircraft down.
What use are spoilers on an aircraft?
Allow an aircraft to descend rapidly.
Vortex Generators are installed in groups of _____.
Groups of two.
Why are Vortex Generators installed in groups of two?
Being installed this way the generators oppose each other.
How do Vortex Generators operate?
The little wings energize the boundary layer with vortices to reduce the stall speed.
What other functions do the Vortex Generators provide?
They improve the controllability and increase the gross weight of the aircraft.
What is the purpose of speed breaks?
To reduce speed.
What downfall do speed breaks have?
They make a lot of noise.
What does STOL stand for?
Short Take-Off & Landing.
What function does STOL have?
This is when the flaps are extended and the ailerons droop down to act as flaps.
What do are Vortilons?
These are Vortex Pilons.
Where can Vortilons be found?
They stick out beyond the leading edge and air hits them to create vortices over the top of the wing.
When do Vortilons work?
At low speed and high angles of attack.
What other component does the same job as Vortilons?
Vortex Generators.
Flaps do what for an aircraft?
Increase the Camber of the Wing.
What secondary function do flaps provide?
Increases lift at low speed.
What three kinds of flap have an “up” position and a “down” position.
Plain Flaps, Slotted Flaps, & Split Flaps
What kinds of flaps is not too effective?
Plain Flaps and Split Flaps
Where are split flaps palced?
On the bottom of the wing.
Split Flaps create a lot of while in the down position?
They create a lot of drag.
Slotted Flaps energize what layer of air?
The boundary layer.
Which Flap is very effective?
The Slotted Flap.
What kind of flap has multiple layers?
The Triple Slotted Flap.
How do Triple Slotted Flaps energize the boundary layer?
They come down flat.
What position are Triple Slotted Flaps in when folded into each other?
The up position.
Which flaps are the most effective?
Triple Slotted Flaps.
What three things do Triple Slotted Flaps do?
1) Increases Surface Area
2) Allow Laminar Flow due to a built in “slot” in the flap.
3) Produces the most induced drag.
What are slats for?
They allow for laminar flow.
Where are slats found?
On the Leading Edges of an Aircrafts’ Wing.
Slots are also known as what?
Fixed Slots.
Where are Slots found?
On the Aircrafts’ Leading Edges.
Why are Slots installed onto an aircraft?
To allow for laminar flow.
Fixed Slots act the same way Slats do in what way?
They do not move.
What is the purpose of a Kueger Flap?
Increase the Camber of the Wing.
What secondary function do Kueger Flaps have?
Increases Lift.
Leading Edge Flaps provide the same function as what other component?
They do the same job as Krueger Flaps.
A Sonic Boom is created when upon what occurrence?
When the sound barrier is broken.
When the Speed of Sound is reached, what happens to Center of Pressure?
It is instantaneously moved farther back.
At low speeds, air is what?
Incompressible.
What is the rule of a Venturi?
As Velocity increases, pressure and temperature _________.
Decreases.
What two parts make up a Venturi?
A Converging Section and a Diverging Section.
How much energy do you have when it goes through a Venturi?
a. More Energy
b. The Same Energy
c. Less Energy
b. The Same Energy
Where are sound waves given off during low speed flight?
They are given off all around the wing.
At High Speed Flight Air becomes ____________.
Compressible.
Why is air compressible at high speeds?
Sound waves cannot dissipate completely ahead of the wing before it catches up to the waves and hits them.
The Converging section of a Venturi does what to these three principles:
a. Velocity
b. Pressure
c. Density
a. Decreases Velocity
b. Increases Pressure
c. Density remains Constant
The Diverging Section of a Venturi does what to these three principles:
a. Velocity
b. Pressure
c. Density
a. Increases Velocity
b. Decreases Pressure
c. Density remains Constant
Below Mach 0.75 is what speed range in relation to the Speed of Sound?
These are Subsonic Speeds.
Mach 0.75 to 1.20 is what speed range in relation to the Speed of Sound?
Transonic Speeds
Mach 1.20 to 5.00 is what range in relation to the Speed of Sound?
Supersonic Speeds
Over Mach 5.00 is what range in relation to the Speed of Sound?
These are Hypersonic Speeds.
Which Speed Range in relation to the Speed of Sound is the most critical?
Transonic Speeds
What is the definition of an Aircrafts’ Critical Mach Number?
This is the point where the entire airfoil is supersonic.
This is the Aircrafts’ Critical Mach Number.
True or False.
The Critical Mach number is the same for every airfoil.
False.
Every airfoil has a different Critical Mach Number.
The Mach Number is the ratio of what?
The Airspeed the Aircraft is Flying.
—————-OVER—————
The Local Speed of Soud.
Why is the Speed of Sound and “Local” Speed of Sound different?
The Speed of Sound is dependant on temperature.
It changes as temperature varies.
What is a round shockwave called?
A Normal Compression Shockwave.
An oblique Shockwave resembles what shape?
A Cone Shaped Structure.
A Bow Shockwave begins at what point at the aircraft?
Starts at the leading edge of the aircraft.
What shape does a Bow Shockwave take after?
Has a vertical half-circle appearance.
True or False.
An Expansion Wave is a shockwave.
False. It is merely a wave.
When a shockwave starts, it does what to the boundary layer.
It deteriorates the boundary layer.
The deterioration of the boundary layer by a shockwave is called what?
Shock Induced Separation.
What may be built into an aircraft to prevent Shock Induced Separation?
Vortex Generators
Sweptback Wings
Thinner Wing Design.
What are two Supersonic Airfoil Shapes?
1) Double Wedge WIng
2) Biconvex Wing
What shape does the Double Edged Wing take after?
A Diamond.
The Biconvex Wing produces what kind of shockwave?
An Oblique Shockwave
The Biconvex Wing is
a. Symmetrically Designed
b. Asymmetrically Designed
c. Could be either.
a. Symmetrically Designed.
High Speed Inlets are installed where?
Within the engine and they stick out slightly.
Why are High Speed Inlets installed?
Air going into some engines have to be subsonic, these components slow the air down.
What is Standard Day?
- Hg / Mercury
- Milliibars
- PSI
- Celsius / Fahrenheit
- Speed of Sound
- 29.92 Hg / Mercury
- 1013.2 Millibars
- 14.69 PSI
- 15 Degrees Celsius / 59 Degrees Fahrenheit
- 661 Knots (Speed of Sound)
What is the primary factor when determining Speed of Sound?
Temperature
Temperature is the primary factor in determining what?
Speed of Sound.
