NIFE Aero Enabling Objectives

What are the different kinds of airspeeds?

- Indicated Airspeed (IAS)- the actual instrument indication of dynamic pressure the aircraft is exposed to during flight - Calibrated Airspeed (CAS)- IAS corrected for instrument/position error - Equivalent Airspeed (EAS)- CAS corrected for compressibility effects. - Total Airspeed (TAS) - the actual velocity at which an aircraft moves through an air mass. EAS corrected for density. -Ground speed - the aircrafts actual speed over the ground (GS = TAS +/- wind component) -ICE-TG

What are the definitions of limit load, ultimate load, and elastic limit?

-(LL)The maximum load factor anticipated in normal operation and that can be sustained without risk of permanent deformation. -(UL) Maximum load factor that can be sustained without structural failure and is 1.5 times the limit load. -(EL)Maximum load that can be placed on a material and RETURN back to original state.

Explain the continuity equation given cross-sectional area and velocity:

-A1V1=A2V2 -The cross-sectional area of the tube is multiplied by the air velocity at any point is equal to the value of any other point in the streamtube. -If cross-sectional area decreases on one side of the equation, the velocity must increase on the same side of the equation so both sides remain equal. -Thus, velocity and area at any point in the streamtube are inversely related.

How do density, velocity, surface area, and the coefficient of lift affect lift production in the lift equation?

-An increase in density, velocity, or surface area will produce greater lift. -Coefficient of Lift- the two aspects of CoL that can be controlled are the shape of the airfoil and AOA. As AOA increases, the CoL increases up to a maximum value (CL Max). Any increase in AOA beyond CL Max causes a decrease in the CoL.

How does the change in Angle of Attack(AOA) affect the pressure distribution around an airfoil?

-As AOA increases, the coefficient of lift also increases until it reaches CL Max, then is causes a decrease in the CoL.

Describe boundary layer separation in regards to adverse pressure gradient:

-As air flows aft from lower static pressure to higher static pressure, it encounters an adverse pressure gradient which impedes the flow of the boundary layer.

In terms of aviation, describe the relationship between humidity and density.

-As humidity increases, density decreases due to equal displacement of air molecules by water molecules. -Since water molecules have less mass than air molecules, density decreases.

Describe the relationship between the coefficient of lift and the Angle of Attack (AOA):

-As the AOA increases, the CoL increases up to a maximum value (CL Max). -CL Max AOA is the most effective angle of attack.

Explain the importance of L/D Max (Lift/Drag ratio Max):

-At L/D max AoA, parasite drag and induced drag are equal. induced dominates at lower velocities and parasitic at higher velocities. -L/D max AOA produces the greatest ratio of lift to drag. -L/D max AOA is the most efficient angle of attack (wing efficiency)Increase in weight or altitude will increase L/D max airspeed, but will not affect L/D max or L/D max AOA.

What are the effects of changes of velocity on total drag?

-At low velocity total drag is high due to induced drag. -Total drag then lowers to its minimum at L/D max, where parasite drag and induced drag are equal. -As this velocity is passed, total drag increases again as parasite drag begins to increase sharply.

Describe a slipping turn and what actions are needed to correct it:

-Caused by opposite or insufficient rudder in the desired direction of turn (toward the outside of turn). Balance ball is deflected toward the inside, due to gravitational pull. -Apply rudder toward the inside of the turn.

Describe a skidding turn and what actions are needed to correct it:

-Caused by using too much rudder in the desired direction of turn (toward the inside of turn). Balance ball is deflected toward the outside due to centrifugal force. -Apply rudder to the outside of the turn.

What is the definition and equation for Total Drag?

-DT= DP + DI -The sum of parasite drag and induced drag

What is the definition of Parasite Drag and its components: form and friction drag?

-Drag not associated with the production of lift. -Form Drag: also pressure, profile drag. caused by flow separation and consequent low pressure wake. primarily dependent on shape. -Friction Drag: due to viscosity, a retarding force called friction drag is created in the boundary layer. turbulent flow creates more friction drag than laminar flow.

What is Steady Airflow?

-Exists only if at every point in the airflow static pressure, density, temperature, and velocity remain constant over time.

Describe how flaps can affect the Coefficient of Lift and CoLMax:

-Extending the flaps changes the chordline, which adds a positive camber to the airfoil. This causes the stalling AOA (CL Max AOA) to decrease. -Visibility on takeoff and landing improves due to flatter takeoff/landing attitudes created by the flaps.

What are the methods to prevent Induced Drag?

-Install devices that impede the span wise airflow around the wingtip such as winglets, wingtip tanks, and missile rails. -Increasing density, velocity, or wingspan.

Describe the different types of flow within the boundary layer:

-Laminar- air moves smoothly along streamlines. -Turbulent- the streamlines break up and flow disorganized and irregular.

Describe the three-axis reference system of aircraft:

-Longitudinal Axis- Passes from the nose to the tail (roll) -Lateral Axis- Passes from wingtip to wingtip (pitch) -Vertical Axis- Passes directly through the CoG (Movement of the long. axis around the vert. axis is yaw)

What are the definitions for the Max Angle of Climb and Max Rate of Climb?

-Max Angle- gaining the most altitude in a given distance -Max Rate-the greatest vertical distance must be gained in the shortest time possible.

What are the requirements to yield max range and max endurance in relation to the power curve?

-Max Endurance- Velocity must be less than L/D Max, and the AOA must be greater than L/D Max -Max Range- L/D Max AOA and velocity

What are the definitions of maximum glide range and maximum glide endurance?

-Max Range- Maximum DISTANCE traveled for a given amount of fuel -Max Endurance- Maximum TIME airborne for a given amount of fuel

Describe the effects of low speed P-factor, slipstream swirl, and what the pilot must do to compensate for each:

-P-Factor- Relative wind below the thrust line, right side producing more thrust due to a higher AOA -Slipstream Swirl- cork-screwing airflow around the fuselage pulling your nose to the left - Pilot must apply right rudder to correct for the left flying tendencies

Explain Bernoulli's Equation given dynamic pressure, static pressure, and total pressure:

-PT = Ps + 1/2qV^2 -(Simply explained) Total Pressure(PT) = the sum of Static Pressure(Ps) and Dynamic Pressure (q) - For a closed system, total pressure is constant; therefore, an increase in static pressure results in a decrease in dynamic pressure, and vice versa.

In terms of stall speeds, what should the takeoff and landing speeds be?

-Takeoff- the minimum airspeed is 20% above the power-off stall speed. -Landing- speed should be 30% higher than stall speed.

What is the definition of the Coefficient of Lift Max?

-The greatest CoL that can be produced

What is the definition of the boundary layer?

-The layer of airflow over. surface that demonstrates local airflow retardation due to viscosity.

What is camber and what are the different types of camber?

-The maximum distance between the mean camber line and the chordline, measured perpendicular to the chordline. -Upper Camber- top surface of the airfoil -Lower Camber- bottom surface of the airfoil -Mean Camber- locus of points halfway between the upper and lower surfaces from forward to aft of the airfoil

Define and describe the aerodynamic center of an aircraft:

-The point along the chordline around which all changes in the aerodynamic force take place. -On a subsonic airfoil, it is located approximately 1/4 of the length of the chord from the leading edge. -It will also be located at the point of MAX THICKNESS of the airfoil or where we have the most positive camber.

Describe the relationship between load factor and angle of bank for a level, constant airspeed turn:

-The ratio of total lift(L) divided by weight(W). (n = L/W) -As Angle of Bank increases, total lift increases so load factor will also increase. - So, we need to increase our total lift by increasing back stick pressure and adding power to increase the load.

What is the General Gas Law?

-The relationship between air pressure (P), density (p), and temperature (T) and where R is a constant for any given gas. -P = pRT -If pressure remains constant, there is an inverse relationship between density and temperature (If temp increases, density must decrease and vice versa)

What is the definition of density and what how does it affect aviation?

-The total mass of air particles per unit of volume. -The distance between particles increases with altitude resulting in fewer particles per unit volume -Therefore, density decreases as altitude increases making an aircraft less efficient due to the lack of air needed to operate the engine and to create thrust and lift.

Describe the pressure distribution around an airfoil:

-Weight is the force of the Earth's gravity acting on the mass of the aircraft (toward the center of the Earth) -Lift is created due to the imbalance of pressure distributions over the top and bottom surface acting upwards. -Drag acts against thrust/forward movement -Thrust acts against drag in order to move the aircraft forwards

What are the effects of gross weight, altitude, and flaps given the stall speed equation?

-Weight- as weight decreases, stall speed decreases because the amount of lift required to maintain level flight decreases. -Altitude- As altitude increases, stall speed increases. -Extending the flaps will decrease stall speed. -Raising flaps will increase camber and increase stall speed

Describe the effects on takeoff and landing performance given variations in weight, altitude, temperature, and humidity:

-Whenever 3 of the 4-H club components are present, expect extended takeoff and landing distances. (high, hot, humid, heavy)

What is the definition of a vector and how is it used in the fundamentals of aviation?

A quantity that represents magnitude and direction and is commonly used in aviation to represent displacement, velocity, acceleration, and force.

What is the definition of chord-wise airflow?

Air flowing at right angles to the leading edge of the airfoil (only flow that accelerates over a wing AKA the only airflow that produces lift)

What is the definition of span-wise airflow?

Airflow that travels the span of the wing, parallel to the leading edge (from root to tip and not accelerated over the wing AKA does NOT produce lift)

What is the definition of a stall?

An increase in AOA results in a decrease in the CoL resulting in decreased lift, increased drag, and an altitude loss.

How does the change in camber affect the pressure distribution around an airfoil?

An increase in camber will increase lift and vice versa

What factors affecting the coefficient of lift can the pilot control?

Angle of Attack and Camber

In terms of aviation, describe the relationship between temperature and altitude.

As altitude increases, temperature decreases at a rate of 2 degrees C per 1000ft until 36,000ft. This rate of temperature change is called Lapse Rate.

Describe the effect of altitude on max range and max endurance performance:

Both Max range and endurance increase with an increase in altitude.

What is the definition of a moment (m) and how does it relate to aviation?

It is created when a force is applied at some distance from an axis or fulcrum, and tends to produce rotation about that point. (M=F x d)

What are the two forces considered aerodynamic forces?

Lift and Drag

Describe Induced Drag:

Portion of total drag associated with the production of lift.

What is the difference between speeds with respect to power-on and power-off stalls?

Power-on stall speed is less than power-off stall speed because at pitch attitudes, part of the weight of the aircraft is being supported by the vertical component of the thrust vector.

Describe the factors necessary to cause an aircraft to spin:

The aircraft must be stalled and yaw must be present.

What is the definition of relative wind?

The airflow the aircraft experiences as it moves through the air that is equal in magnitude and opposite in direction to the flight path.

What is the definition of pitch attitude?

The angle between an aircrafts longitudinal axis and the horizon

What is the definition of Angle of Incidence (of a wing)?

The angle between the aircrafts longitudinal axis and the chordline of the wing

What is the definition of Angle of Attack (AOA)?

The angle between the relative wind and the chordline of the airfoil

What is the definition of wing area?

The apparent surface area of a wing from wingtip to wingtip. (more precisely, it is the area within the outline of the wing in the plane of its chord, including the area within the fuselage, hull, or nacelles)

In what ways can wind shear be a hazard during the landing environment?

The hazardous situation develops with the pilot's response to the change in performance. An overly aggressive or passive response to change in performance creates the hazardous scenario while low to the ground.

What is the difference between a true and an indicated stall speed?

The indicated airspeed at which an aircraft stalls can be considered constant, but the true airspeed at which it stallsincreases with altitude.

What is the definition of wingspan?

The length of the wing from wingtip to wingtip. (not just the wing on one side of the fuselage)

What is the definition of flight path?

The path described by its center of gravity as it moves through an air mass.

Describe the process and actions necessary to recover from a spin:

The pilot must reduce AOA and use opposite rudder to correct the yaw input.

What is the definition of Center of Gravity (COG) in relation to aircraft?

The point at which all weight is considered to be concentrated and about which all forces and moments are measured.

What is the chord?

The precise measurement between an airfoils leading and trailing edges measured along the chordline and will typically vary between the wingtip and the root.

What is the definition of wind shear?

The sudden change in wind direction and/or speed over a short distance in the atmosphere.

What are the requirements for an aircraft to be in equilibrium flight?

The sum of all forces and the sum of all the moments around the center of gravity are equal to zero. (An aircraft in straight and level flight at a constant velocity must have the sum of thrust, drag, lift, and weight = 0)

Describe the relationships between the wings during a spin:

The wings are unbalanced and there is a difference in AOA between them

What are the requirements for an aircraft to be in trimmed flight?

When there is no rotation around the CoG