Instrumentation: Air Data and Gyros
Instrumentations
Instrumentations
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Lernkarten
Gyro: how is the floatd fluid compass being used?
to get high directive force one has to reduce the heavy weight of strong magnets by the buoyancy (Auftrieb) of an attached (befestigt) float in the damping fluid
Gyro: Where would teh direct reading compass be horizontally?
Only at the magnetic equator => Because of the inclination => Other place he will be a little be tilted
Gyro: How you can damp the aperiodicity of a direct reading compass?
by using several short magnets
Gyro: Why is the housing of a DRC = direct reading compass filled with liquid ?
for damping purposes
Gyro: What is teh reason that a DRC suffers from a spin error ?
The spin error occur, when flying circles after leveling off, the reason is that the liquid inside rotate due to its friction against the housing
Gyro: Acceleration Error DRC?
ANDS => Accelerate North Decelerate south
Gyro: Turn error when max and min?
turn error is at max when turning through north and south and is zero when turning through east or west
Gyro: Right Turn at the northern hemisphere ?
the compass rose, which is mounted pendulously, undershoots at the pivot and moves into the same position like the aircraft yaw axis ==> Hinterdrein => UNOS (undershoot North Overshoots South)
Gyro: Left turn on the northern hemisphere => DRC
Direct reading compass läuft voraus => UNOS = Undershoot if flying towards North , Overshoot if flying South
Gyro: When accelerating on an easterly heading in the Northern hemisphere, teh compass card of a DRC will turn?
Clockwise giving an apparent turn toward the north
Gyro: What are reasons taht a compass swing has becoe necessary?
Typically one time per year, after lightning strikes, change or replacement of radio equipment, hard landings
Gyro: When an aircraft on a westerly heading in the northern hemisphere accelerates, the effect of the acceleration error causes teh magnetic compass to?
Indicates a turn towards the north
Gyro: Which error occurs on teh DRC if an aircraft decelerate in the northern hemipshere, following a landing in a northerly direction?
No error
Gyro: Turn effect are gretatest where?
Turning errors are greatest on north/south headings, and are greatest at high latitudes
Gyro: Out what does the compesasting system for the compass consists of?
The compensating system consists of two small rotatable units, each of them carrying small magnets => one is compensate the North South )N/S) axis and the other one for the East West (E/W) axis
Gyro: The way a copass becomes calibrated?
Compass swing => a reference compass mounted on a tripod in front of the aircraft => steps of 30 degrees
Gyro: What is the use of compass liquid?
the magnetic assembly is required to be aperiodic = that it should settle down quickly to a steady indication after being displaced by turbulence 0=> several short magnets are used instead of one longer one=This keep the mass of the assembly near the cent
Gyro: What is a parallax error?
Parallax error is a difference in the apparent position of an object viewed along two different lines of sight
Gyro: What is teh error of a DRC f a aircraft, which is flying in an easterly direction at the magnetic equator, accelerates?
no error
Gyro: Which error of the DRC for which hemisphere of the earth is mentioned with ANDS
Northern hemisphere => acceleration error: Accelerations North, Deceleration south
Gyro: Which error of teh DRC for which hemisphere of the earth is mentioned with UNOS?
Northern hemisphere; turn error; undershoot North, overshoot south
Gyro: How is the vertical Card damped?
the vertical card compass is damped by utilization of eddy current effect
Gyro: Flux detector?
a magnetized type rotorless synchro => A sinusoidal AC current in the inner excitation coil produces a changing magnetic flux in the iron made spider leg
Gyro: How does a flux alve measure the direction of teh earzh's magnetic field?
The sensor coils are affected by sinusoidal (three phase flux valve) or triangle (two phase flux valve) currents which causes saturation of their iron cores in relation to the frequency of the currents. This forces the earth's magnetic field to enter and to leave the iron core nd as a result the direction of teh earth's magnetic field can be measured in the senor coils.
Gyro: At which place in teh aircraft is the flux valve typically mounted?
Typically in the wing tip because the intensity of disturbing magnetic fields is very low there. = >minimize magnetic disturbances as much as possible
Gyro: How many excitation coils and sensor coils can be found in a three phase flux valve ?
One excitation coil and three sensor coils
Gyro: Why it is necessary for a flux valve to be mounted like a pendelum?
The flux valve has a hang vertical during unaccelerated flight to be able to measure the direction of the earth's magnetic field as accurate as possible.
Gyro: How many excitation coils and sensor coils can be found in a two phase flux valve?
Two excitation/iron coils and two sensor coils => Each core carries two coils, one for excitation (red = Erregung) the other one for sensing (blue=Fühler)
Gyro: By a Flux valve what blocks rapid changes of the measured valve due to accelerations/decelerations and turns?
the output from the flux valve is coupled to the indicator fitted with a low pass filter
Gyro: What is the different by the voltage between two and three phase flux valve?
By a two phase flux valve the power supply of the excitation coil is a triangle voltage instead of sinusoidal
Gyro: A remote compass system?
1. DG: to hold a heading in an aircraft for a short time => in the end the gyro will drift away=> Turn just in time immediately
2. second sensor: flux valve => connected to the indicator via a low pass filter => the task of blocking inaccurate measurements caused by unwanted flux valve oscillations that occur during turbulence or aircraft acceleration/Deceleration
=> When synchroization Indicator moves during flight = compass system is ok => Switch to D.G. = every 10 to 15 min according to the magnetic compass during non-accelerated flight => adjust
Gyro: Remote compass, Max allowed error of teh complete remote compass system
In the range of +/- 2 degrees
Gyro: Remote compass system advantage?
that the gimbal error disappears after leveling off, because the gimbal error is not a gyro precession error
Gyro: Remote compass system => Compass System failure ? DG kaput?
When during flying a turn, the new heading indication at the HSI follows the new heading very slowly but correctly the DG will be out of service. Because the DG is responsible for the rapid indication in every situation
Gyro: Remote compass system => Failure of the flux valve?
If the indication quickly follows during a turn the flux valve is probably wrong => Pilot should check the heading indication regarding the magnetic compass
Gyro: Explain teh meaning of A, B and C error of a remote compass system?
A-error: Alignment error or installation error B-error: East/West error C-error: North/South error
Gyro: WHat is teh reason for the acceleration/decelration error of a flux valve?
The reason is that the flux valve is mounted as a pendulum
Gyro: What is teh purpose of the low pass filter which is part of teh remote compass system?
Th purpose of the low pass filter is to reduce the effect of the flux valve's oscillation which occurs at accelerations, decelerations and during turns
Gyro: Is a remote compass system free from gimbal error ?
No, the remote compass suffers from the gimbal error
Gyro: Is teh indication of a remote compass system stable and reliable for short time, long time or both?
The indication of a remote compass system is stable and reliable for short time and long time
