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Home Principals of flying Magic number 4 - part II

The magic number 4 - part II

Return to:  Magic number 4 - part I ... Four controls

Four basic controls.

  • Throttle (1).  This is simple control of the engine power.  It acts directly to the thrust.  To increase the thrust, pilot needs to add power simple by throttling up.  Added thrust will speed up the plane.  Increasing speed will make the air resisting more and the drag will increase eventually balancing the new thrust force at the new speed.  There is one additional effect of speeding up.  With higher speed of the airflow around the wing the airplane will receive additional lift.  Unless we do something the airplane will start climbing.
  • Elevator (2).  This control changes the airplane pitch by moving an elevator - a piece of horizontal stab (a little "wing" located in the tail of the plane).  By changing the airplane pitch (tilting the airplane nose up or down) we can control how much lift the wing creates.  In general the higher the pitch is (within limits of course) the more lift wings creates.  But the lift does not come for free.  The more lift wing creates the more drag it gets.  That makes control a little more complex.  You will need to add power (throttle up) to keep the same speed during the climb. RC transmitter
  • Ailerons (3).  This control make the airplane to bank.  By moving a part of wing's trailing edge (ailerons) we can increase the lift at the one wingtip at the same time decreasing the lift at the other wingtip an that creates a twisting force making the plane to bank.  Banking the airplane is very important element of making the airplane to turn.  When you bank the plane the lift direction, which is always perpendicular to the wing surface, will not be in the line with gravity any more.  Part of that force will be "pulling" the plane sideways changing the airplane heading.  So we have a turn.  Quite ugly, because we are pulling the plane sideways.  To make a "coordinated turn" we need to point the nose in the new direction of flight.  For that we have fourth control.
  • Ruder (4).  This control the yaw.   By moving a ruder - a piece of vertical stab (a "fin" located in the tail of the plane) we can make the nose pointing left or right.  Of course pointing the nose left or right does not make the airplane turn, but rather make it flying sideways (at least for a while). Using ruder with ailerons together we can make"coordinated turn" - the most efficient way of changing the airplane's heading.

Flying the airplane is not just "hanging it in the air".  Whatever goes up, must go down, right?. Better to do it in controlled way, otherwise the flight will be a subject of "breaking news" on TV.  So before we start flying, let's first understand all four phases of every flight.  Another magic "4".

Go to:  Magic number 4 - part III ...