<< Page 15 Page 16: Page 17 >>   Standard Airplane Controls An airplane has three axes that a pilot can control, that define the plane’s attitude and flight path: Roll, Pitch, and Yaw: The Roll axis goes horizontally from the nose to the tail, usually through the pilot. Rolling means banking: If an airplane “rolls right”, that means the right wing is dropping and the left wing is rising. This not absolute, but relative to the pilot: an agile airplane may “roll right” 360 degrees and end up at the same orientation it started. Or, an airplane climbing or diving vertically can “roll” around the vertical axis. In other words, rolling right means rolling clockwise (as the pilot sees it), and rolling left means rolling counterclockwise, about an axis from the nose to the tail. Rolling is achieved by pushing the joystick to the side, or by turning the control wheel. Pushing the joystick left, or turning the wheel left, causes the plane to roll left. These inputs cause ailerons, surfaces at the trailing edge of the wings, to deflect up or down, so one wing generates more lift than another. Spoilers are also used in some aircraft – these are plates in the middle of the top surface of the wing which deflect upwards in order to kick air upwards, cause separation, and reduce lift. If the pilot pushes the stick left, for example, the left ailerons go up (and sometimes the left spoilers). This causes air moving over the left wing to go up rather than down (or just to go down less), so the left wing is producing less lift. Meanwhile, ailerons on the right wing deflect down like flaps, increasing wing camber and pushing air downwards more, so that wing produces more lift. This causes the plane to roll to the left. Now, the Pitch axis goes horizontally from one side of the airplane to the other, usually form wingtip to wingtip. Pitching up or down means the nose of the aircraft points further up or further down, relative to the pilot. For example, imagine an airplane flying horizontally but rolled 90 degrees on its side (this is called knife-edge flight). Pitching up would cause its nose to face a new direction (turn), but the plane would remain flying horizontally. Normally, though, airplanes rarely bank that much, so pitching up and down usually causes the nose of the plane to point higher or lower. Pitching up and down is achieved by pulling and pushing (respectively) the joystick or control wheel. (This is why “pull up” is used to mean “get the nose pointed away from the ground” – it involves pulling on the stick or wheel, to get the nose up). These stick inputs cause the elevators, hinged surfaces on the back of the horizontal tail, to deflect up or down. If they deflect up, the tail blows air up and is thus pushed down, and the nose goes up relative to the pilot. If the elevators deflect down, the tail generates more lift and goes up, and the nose goes down. The Yaw axis goes vertically right through the middle of the fuselage. Yawing left or right means the nose goes to the left or to the right as the pilot sees it, like a car making a turn. Of course, if the plane is banked, this left/right will have a component of "absolute" up or down. For example, imagine an airplane rolled 90 degrees on its left. Yawing to the right would cause the nose to go up, in absolute terms. (and pulling up, as we have seen, would cause the plane to turn to the left). Yaw is achieved by pushing the rudder pedals. A pilot has a pedal under each foot. Unlike car pedals, they are the same size and shape as each other, and are connected such that if one goes forward, one goes back towards the pilot. Pushing on the right rudder pedal (where a car’s accelerator is) causes the plane to yaw right. This is actuated via the rudder, like on a boat. At the back of the vertical tail is a hinged surface. If it hinges out to the right, it will deflect air to the right, pushing the tail to the left and the nose to the right (yawing right). It is by controlling the pitch, roll, and sometimes yaw, that a pilot makes an airplane fly a desired flight path.   - - - - - - - - - - - - - - - - - -   Summary: Controls: -An airplane’s three axes are the pitch axis (nose up / nose down – the axis is the lateral axis), the roll axis (bank right / left – the axis is the longitudinal axis) and the yaw axis (turning right / left like a acr – the axis is the vertical axis). -Pitch is controlled by the elevators, in the horizontal tails. Roll is controlled by the ailerons, on the trailing edge of the wings, usually out towards the wingtips. Yaw is controlled by the rudder, on the vertical tail. -The elevator and ailerons are controlled by the joystick or control wheel (forwards is nose down, back is nose up, left is roll left and right is roll right), ad the rudder is controlled by rudder pedals (push right pedal to yaw right, left pedal to yaw left)