vortexknology, airfoils

• Kinetic Energy: The energy an object has just by being in motion....KE=1/2MV^2
• M=Mass, V=Velocity



• Potential Energy: The energy an object can release based on its position relative to other objects and/or height above the ground.
• PE=MGH, M=Mass, G=Gravity (9.8m/s^2), H=Height

• With the understanding that Kinetic Energy is energy in motion, lets look at airflow over the airfoil.
• If we replace the (M) in the KE equation with the Greek letter Rho (ρ), we have the formula 1/2ρv^2
• The next is area.
• In order to see how this equation works, it can be simplified to the following:

A1V1=A2V2

A=Area

• Example: using general knowledge measurement's,

10sq.ft(100mph)=5sq.ft(V2)

V2=10sq.ft(100mph)/5sq.ft

V2=200mph

Notice the velocity change

  

Energy cannot be created or destroyed. It is transformed from one form of energy to another. Therefore, lift is generated not created.

• Lift=Cl1/2ρV^2S
• Cl=Coefficient of Lift

Cl is determined by the type airfoil and the Angle of Attack (AoA)

• S=Wing Area

Determined by wing configuration., i.e. Flap and/or Flap and Slat setting

Do you see the Kinetic Energy formula in the Lift equation? KE=1/2MV^2

1/2ρV^2, Mass has been replaced with air density, ρ.

With the knowledge of Bernoulli's Principle and now the lift equation, see if you can spot bernoullis principle in action.

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Wings come in many shapes and sizes. In fact, there is a number for each shape of wing design. That number is known as the NACA number. Up until recently there were only four numbers in the NACA number but now some have five. To learn more, click the links below.

http://airfoiltools.com/airfoil/naca4digit

http://akiti.ca/NACA4Bkgrnd.html

The C-5 Galaxy can take off with a max gross weight of 840,000lbs. It holds 332,500lbs of fuel and the basic empty weight is roughly 375,000lbs. This weight varies with the tail number and configuration of the plane.

Do you think the C5 has a high speed wing or a high lift wing? 

It has a Low Speed/High Lift wing.

In the following video, Watch for the following and think about the crews actions in the cockpit. Watch the wings as the C-5 accelerates and how they go from drooped to straight to flexed as they take the weight of the C-5. Notice the Slats on the leading edge.

• Advancing Throttles Now
• The pilots advance the throttles and the engineer starts the clock...15, 20, TIME
• At 25 seconds (TIME), the pilots release the brakes and the plane begins to accelerate.
• At certain time and distance intervals the plane has to be going a certain calculated speed or faster. If not, the takeoff is rejected.
• My experience on the C-5 at 840,000lbs in Frankfurt Germany at night in the rain...Brakes release at TIME and the plane sits there for a second. Roll, roll and roll...finally V1, Roll, and roll some more, V2 rotate. used 11500 ft of a 13000ft. rwy

Flaps are devices on the trailing edge of the wing that are designed to increase lift. However, when lift is increased, Drag too is increased.  The drag caused by lift is known as induced drag. 

Lets talk about how flaps help with lift.

When the flaps are up the aircraft is in the clean configuration. With the flaps and gear down the plane is in the dirty configuration.

The following is an example of Flap and Slat Extension on the C-5 Galaxy.

• When the flap handle is moved to 40%, the flaps extend to 40% on the trailing edge  wing and the slats extend to full down position on the leading edge of the wing. Because the flaps move back and down, the wing area has increased. Lift=Cl1/2ρV^2S
• Recall the Lift equation where S=Wing Area.
• If the wing area is increased and the amount of lift required remains unchanged, what has to change in the formula? Velocity! 
• The velocity decreases because the wing area increased. 
• For short Field Takeoffs, 62.5% flap setting is used and for landing, Flaps Landing.
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• The following video is a sequence of the Boeing 727 Slotted Fowler Flaps and slats in operation.
• Notice the Screw jack that moves the flaps. Look at the cover as the flaps retract. Now you know why planes have those extensions on the trailing edges of the wing.

With the recent news about the Boeing 737Max and the two fatal crashes,  nearly everyone who has seen a story about the max has heard the term Angle of Attack.  What is the Angle of Attack.

Before explaining what AoA is, some key terms need to be defined.

• Angle of incidence: The angle the wing of an airplane is mounted to the fuselage.
• Relative wind: The direction of wind over an airfoil relative to the aircrafts movement.
• Chord Line: The imaginary line from the leading edge to the trailing edge of the wing.
• AoA:  The angle of attack is the angle between the chord line of the wing and the relative wind.

Why is A0A so important? 

Have you really ever watched a plane land? The nose is up but not climbing? Why?

The flaps are down and if equipped, the slats too are down.

How did the chord line change?

 What happened to the camber?

Future