Basic Flight Aerodynamics (PART -14)

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                                                                         Aeroelasticity
                                                    
                                                                                      
 *Aeroelasticity: Aeroelasticity is the science which studies the intertia elastic & aerodynamic forces. The study of mutual interactions that take place within elastic & aerodynamic forces acting on the structural members exposed to an airspeed & influence of the design. Aeroelasticity can be divided into two fields. They are  1) Static aeroelasticity ; 2) Dynamic aeroelasticity.

*Static Aeroelasticity: Static aeroelasticity studies the interactions between the aerodynamic & elastic forces on an elastic structure of  an aircraft.

*Dynamic Aeroelasticity: Aeroelasticity interactions among of an aircraft's aerodynamic,inertia & elastic forces.

 *Effects Of Aeroelasticity : 
                                                 ~ Wing Divergence;
                                                 ~ Control Surface Reversal;
                                                 ~ Flutter;
                                                 ~ Buffet;
                                                 ~ Dynamic Response.


*Wing Divergence: 
~ Divergence occurs when a lifting surface deflects under aerodynamic loads.
~Aerodynamic load increased, the twisting effects on the structure increased.
~Load increased, deflects the structure.

*Control Surface Reversal: Control surface reversal is the loss of the expected response of the control surface due to structural deformation of the main lifting surface.

*Flutter: Flutter is a self starting vibration that occurs when a lifting surface bends under aerodynamic force.Whether the load reduced, the deflection reduces & restoring the original shape.

*Buffet: It is a high frequency instability caused by the airflow disconnection from the airfoil or shock wave oscillation.It is always called a random forces vibration.

*Dynamic Response: Dynamic response or force response of an aircraft to gusts & external atmosphere disturbance.

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Basic Flight Aerodynamics (PART -13)

Basic Flight Aerodynamics ( PART - 12 )

                                  Basic Comparison Between Powered Flight & Glider

                    Powered Flight                                                        Glider  

                                                                                                           

1.Powered flight has engine to maintain the                 1. It has no engine to maintain but it has

  flight or balance an aircraft & aerodynamic forces.       initial airspeed to control flight.            


 2.It is used for the commercial purposes or business   2. Glider is used for adventure,sky
       purposes.                                                                  diving or experimental purposes.

 3. Biggest valuable transport industry in the world.      3. Individual developing industry.

 4. Powered flight is so expensive than glider.               4. Glider is so cheapest than other.

 5. Easy to handle & maintenance.                              5. Not easy to handle, it's fly path
                                                                                   consider towards the initial airspeed.

Basic Flight Aerodynamics ( PART - 11 )

Kinetic Heating: Heating effect occur for supersonic aircraft. Surface area of supersonic range 2000 degree c; Aluminium tolerant range 100 degree c; Titanium & stainless steel: Glass is used for thin of streamline for smoothly. Kinetic heating also called heat effect.

Normal stall:  Normal stall is the reduction in the lift co-efficient generated by an airfoil as angle of attack increases. This occurs when the critical angle of attack of the airfoil is exceeded. 

Area ruling: This is also known as transonic  area ruling, which is a design technique reducing  an aircraft's drag at transonic & supersonic speeds, particularly between mach 0.75 &1.2

Basic Flight Aerodynamics ( PART -10 )

Few Important Definition On Aerodynamics : 

Angle Of Attack  with relative airflow

• Angle Of Attack (AOA) : Generally , AOA is the angle between airfoil chord line (line of a body) & relative airflow which acts oppositely. The AOA is so important in fluid dynamics, becuse Aircraft take off, land & gain altitude always depends on that angle.
• Angle Of Incidence (AOI) : Longitudinal axis is making angle with aircraft (airfoil) wing is called Angle Of Incidence (AOI). It is also known as Manufacture angle.
• Laminar Airflow : In which the streamlines are smooth & fluid elements move regularly along a streamline. 
• Turbulent Airflow : In which the streamlines are break up & fluid elements move in a random & irregularly.   
• Shock Stall : Shock stall is the separation of boundary layer & making disturbance. It is occurred, when the airflow is near by critical mach number (0.8-0.9).
• Sonic Bang : When the aircraft (airfoil) move fast & faster at subsonic range, then toward to the sonic & supersonic range. when the airflow is passed sonic range or sonic range area is called sonic Bang.              

Basic Flight Aerodynamics (PART -9)

Four main flight forces: 

Weight: Weight is the force of gravity. It acts in a downward direction—toward the center of the Earth.

 Lift: Lift is the force that acts at a right angle to the direction of motion through the air. Lift is created by differences in air pressure.

Thrust: Thrust is the force that propels a flying machine in the direction of motion. Engines produce thrust.

 Drag:  is the force that acts opposite to the direction of motion. Drag is caused by friction and differences in air pressure.

Four main flight forces of an airfoil

                          

 

Basic Flight Aerodynamics ( PART -8 )

Critical Mach Number :  When the airflow  is in subsonic range, mach number will be near by  1.0 , approximate 0.8 - 0.9 ( where airflow speed is so high ).

Speed Of Sound : Speed of sound always follows on temperature .The speed of sound drops by approximately 45 m/s. Considering Temperature & height, speed of sound are different.



      Height (km)    Temperature (dk)      Speed of sound(m/s)

    Sea level                    288                           340.3
    
      3.0                            269                           328.6

      6.0                            249                           316.5

      9.0                            230                           304.0

    12.0                            217                           295.0