Instrumentation: Air Data and Gyros
Instrumentations
Instrumentations
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Cartes-fiches
Tolerance Servo Altimeter
max. 100'000 ft +- 30 ft
friction
Reibung
linkage
Verkettung
What is VMO calculated from?
EAS
Air Data Computer gibt die Folgenden Daten?
Take off Speed => Welche Speed bleibt immer Konstant bei jedem Take Off
CAS => Density decreases with altitude => Constant weight the T/O TAS varies with altitude, but the T/O EAS (or CAS, because they are equal) remains the same irrespective of the AP attitude
Limits VSI
+- 200 ft/ min Temperatures from -20 zu + 50 Grad
+-300ft ll other temperatures
The altimeter is subject to static pressure error. This error varies according to:
TAS and AOA
To be as accurate as possible, an airspeed indicator must be calibrated according to the following formula:
Saint-Venant, taking into account the air compressibility
The airspeed indicator of an aircraft is provided with a moving red and white hatched pointer. This pointer indicates the:
max. speed in VMO operation versus altitude
The input data source of the air data Computer are
The Total pressure from the pitot tube, static pressure from the ports and the Total Temperature from the TAT probe
Servo assisted altimeter contains an
Servo assisted altimeter contains an induction pick off device = electro-magnetic sensor => simple pressure altimeter comprises a mechanical linkage
Pressure altitude may be defined as:
pressure measured in the standard atmosphere
higher altitude => Position error was passiert?
higher altitude => Position error increases as the aircraft speed increases = High Mach numbers = bigger position error
The reason for having a square law compensation in teh airspeed indicator mechanism is:
the differential pressure increase withe the square of the airspeed
Gyro: prescession
movement => an external force or torque is applied to change the direction of the rotor axis, the gyro does not move in the plane of the torque applied, but moves in a plane perpendicular to that of the thorque
Gyro: rigity
hold the position in space ==> Starrheit
Gyro: In the building principle of a gyro teh max. rigity is obtained through teh cncentration of teh mass:
on the periphery and with a high rotation speed
Gyro: Degrees of freedom of rotation => One degree of freedom?
teh gyro is simply a notable device => no gimbal
Gyro: Degrees of freedom of rotation => 2 degree of freedom?
the gyro is a rotatable device, mounted on one gimbal
Gyro: Degrees of freedom of rotation => 3 degrees of freedom?
teh gyro is a rotatable device, mounted in two gimbals
Gyro: Degrees of freedom of precession; One degree of freedom?
teh gyro is mounted in one gimbal and can perches around one axis
Gyro: Degrees of freedom of precession; Two degrees of freedom?
teh gyro is mounted in two gimbals and can precess around two axes
Gyro: Freedom of rotation?
the aircraft moves around a stable gyro
Gyro: Freedom of precession?
the gyro's rotation axis is not stale, its rotation axis changes its direction in space
Gyro: gyro wander may be split up into ?
gyro topple and gyro drift
Gyro: Gyro topple
max. at the geographic equator => slow movement of the gyro axis in the vertical plane
Gyro: Gyro drift
max. at the poles => slow movement of the gyro axis in the horizontal plane
Gyro: How many degrees and in which direction does a spinning gyro precess in case of a torque input?
90 degrees in direction of rotation => sonst gimbal lock
Gyro: What are possible reasons for true topple and drift?
friction of bearings (Orientierung, Lage), unbalance of gimbals, unbalance of gyro mass
Gyro: Which ome of teh two gyros (spin xis vertical / horizontal) can suffer from apparent topple and apparent drift?
directional gyro
Gyro: Artifical horizon?
rotation axis is vertical => this vertical gyro is two-gimbal suspended so an aircraft may turn around that gyro without any reaction of the gyro artificial horizon => a two degrees of freedom gyro ==> limitations less then 90 degrees sonst gimbal lock
Gyro: Considerng an air driven aertifical horizon, when an airplane accelerates during the the T/O run, what will be teh result in pitch?
pitch up
Gyro: errection system?
operates by gravity, centrifugal and acceleration forces
Gyro: two reasons that may case a gyro to topple out of its ideal position
a) the earth transport rate and the aircraft transportation rate = apparent topple b) mechancical static and dynamic unbalance of the gyro = true topple
Gyro: how is the erection system of a pneumatic artifical horizon constructed?
To adjust the gimbals inside the instrument as well as the gyro relative to its housing => system to precess the gyro fast into its ideal position => the gyro and the related gimbals become forced mechanically into a position that the gyro is erected ver
The gyros axis of an electric artifical horizon is tied
in direction to the centre of the earth
Gyro: Acceleration Error
the reason for change in position of the pendulums ==> Gibt pitch an
Gyro: What is the task of the cage knob of an artifical horizon?
To adjust the gimbals inside the instrument as well as the gyro relative to its housing
Gyro: Roll error
gimbal at the bottom heavy => a torque which forces the indication to read a bank attitude which does not really exist => anti clockwise ==> rechtskurve
