Turn and slip indicator
A turn coordinator is an electrically driven gyroscope. It is used to indicate the direction of rotation and speed of rotation of the aircraft about its vertical axis. The turn coordinator was initially the central instrument in equipment for instrument flight.
There are two types of turning pointers: The original turn indicator and the later-developed turn coordinator. In German, both instruments are referred to as " turn coordinator ", which can lead to misunderstandings. However, the term " curve coordinator " could not prevail in the German language area.
Usually, even a second instrument, the ball dragonfly, built in the turn and bank indicator. Thereby the quality of the turn coordination is shown. This combination led to the designation turn and bank indicator, often abbreviated to " T & B". This designation is indeed common, but actually wrong if it would turn and slip indicator hot.
Unlike the artificial horizon of the turn indicator does not show the location in space, but the rotational speed of the aircraft to the high - or the high - and longitudinal axis. The position in space must be inferred from the interaction of these display ads for other flight instruments, which is quite abstract. Nevertheless, the turn coordinator is an essential for safety blind flight instrument because he, unlike the artificial horizon, neither stagger nor can migrate, but is always right.
Turn and bank indicator can also be used on ships.
- 2.1 Structure
- 2.2 Functionality
Turn and bank indicator
Construction
The turn indicator is based on a gimbled suspended gyroscope which has only two degrees of freedom. ( One of these degrees of freedom is the rotation around the top shaft. However this is at a roundabout by definition always present. Therefore it is eg not counted in the Anglo- Saxon countries. In the Anglo- Saxon usage A turn and thus has only one degree of freedom. )
The top shaft is mounted parallel to the plane transverse axis. They differ by the fact that, being the turn indicator, the movable frame, wherein the rotor is hung so mounted that the axis of rotation of the frame is parallel to the longitudinal axis of the aircraft, while tilting the turn Coordinator the axis of rotation of the frame 30 ° relative to the aircraft longitudinal axis is. Which causes the turn indicator, only rotations around the vertical axis of the aircraft ( yaw) indicating during the turn coordinator indicating both rotation about the vertical and about the longitudinal axis (roll).
Operation
If the aircraft is flying and a curve that is the plane to rotate about the vertical axis, tilting the axis of rotation of the gyroscope because of the precession. This tilting movement, which is dependent on the rate of turn is indicated by a pointer.
Depending on Kreiselpräzessionsrate the aircraft symbol of the turn coordinator case leans towards the left or right. The faster is the angular velocity, the greater the gyroscopic precession, and the transverse inclination of the aircraft symbol.
In case of failure of the artificial horizon can be replaced with the turn coordinator at least one of the two axes. In combination with the altimeter, airspeed indicator, possibly the speed display and the variometer important information about the attitude still can be derived.
Use
In powered aircraft you hit the turn and bank indicator now mostly in the shape of the curve Coordinator at. Since usually long distances straight flight only be interrupted by short curves for course correction in powered flight, serves the Turn & especially to maintain straight flight. Fulfills this purpose the curve coordinator at best, since each curve is first introduced by rolling. The curve coordinator responds to an incipient curve much more sensitive than the classical turn and bank indicator.
For helicopters and gliders, however, the curve coordinator with his " mixed message " of two different axes of rotation for various reasons is not suitable. Here you will find only the classic turn and bank indicator.
Ball dragonfly
Construction
The dragonfly, also called " inclinometer ", is a liquid- filled, curved glass tube, in which a steel ball can move back and forth. The ball in the bubble level indicates the direction of the dummy solder, ie the vectorial sum of the centrifugal force and gravity, to.
Operation
By dragonfly a judgment to be made as clean a curve is flown; how well the curve flight " coordinated " is. The ball in the level remains between the two vertical guides when offset the forces occurring in straight flight straight and thus the aircraft flies a coordinated turns. If the ball is outside the two marks, the plane either a sliding curve (English skid ) makes ( banked too low ) or a lubricating curve ( engl. slip ) ( banked too large).
When the top surface of the aircraft icon to the right or left of the touched mark, to fly with a rotational speed of 3 ° / sec and 360 ° in 2 min. This is called a standard curve (german standard rate of turn ). Thus, the aircraft flies a complete circle in two minutes. The ball dragonfly should always just stand in the middle, as the plane pushes else ( outwards) or lubricates (inside).
Interplay of both subinstruments
It makes sense that these two instruments have been combined. Both together say something about the curve behavior. As can be seen from the adjacent diagrams, with the same cornering speed can about the longitudinal axis ( airplane symbol to the right inclined ) either a coordinated curve or a slip ( dragonflies ball in this example on the right ) or skid ( dragonflies ball in this example on the left ) are flown. This then may lead to non-compliance to a spiral dive ( engl.spiral ).
To avoid such uncoordinated curves, the pilot must in the turn on deviation of the ball from the middle step " in the ball," ie enter into the rudder, which corresponds to the position of the ball.
Hazards
The curve coordinator, as described above, a 30 ° oblique mounted gyroscope. This means that the device indicating both the rollers and the yaw. If the aircraft rolls, the display of the curve coordinator adds the roll rate by a certain factor for yaw rate. Only when the aircraft rolling over, the unit will return exclusively to the yaw rate. Pilots who are not familiar with this principle, might have difficulty with the use of the curve coordinator, by seeing example, in roll and a display, but interpret them as a gymnastic display.
Older, purely mechanical barometric vertical speed function without auxiliary power, but the turn and bank indicator function required electric drive power for the gyro motor ( for example, 36 V/400 Hz three-phase ). Turns out the power supply, the gyro yet still continues to rotate for a few minutes until no indication of the angular velocity is possible. The ball dragonfly working without auxiliary energy.