Instrumentation: Air Data and Gyros
Instrumentations
Instrumentations
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Cartes-fiches
Gyro: What is the RPM range for a typical artifical horizon?
15'000 - 20'000 RPM
Gyro: What is teh reason to limit teh freedom of an artifical horizon in pitch between 80 and 85 degrees?
To avoid a gimbal lock
Gyro: What is the angular velocity of a typical gyro erection system?
3 Degrees to 5 degrees per minute
Gyro: Remote vertical Gyro?
today in aircraft remote vertical gyro are used to overcome the true and apparent topple, erection switches on the gyro housing (inner gimbal) are used to control two torquer motors
Gyro: methode to overcome the turn error in a remote vertical gyro
to overcome the turn error in such a remote VG is the use of cut out switches as soon as the bank attitude exceeds ca. 6 degrees => cut out switches operate for avoiding the acceleration/deceleration error
Gyro: Remote Gyr Indication von wo her die Infos?
teh pitch and bank info is taken from the corresponding synchs which are mounted at the outer gimbal
Gyro: Remote Gyro Indication => test bottom?
if the test button is pressed only the servo circuit is tested
Gyro: What is teh formula for apparent topple of an aertifical horizon caused by rotation of teh earth?
15 * cos(a)
Gyro: What is the reason for the roll error of a pneumatically driven artifical horizon during acceleration/deceleration?
the higher weight of the bottom of the gyro compared with its top
Gyro: Which error of a pneumatically driven artifical horizon is compensated by teh forward tilt construction?
The turn error
Gyro: What is the task of the cut out switches of the remote vertical gyro?
To cut off the erection system during accelerations/decelerations and turns
Gyro: Two ball errection system
to keep the horizon up to 10 or 15 minutes operative even after complete loss of its electrical power supply => plate on the top rotates opposite=> if the gyro is toppled, the rotating balls have to follow the gravity force and will change their position
Gyro: Andere Variante für two ball errection system?
uses a movable weights instead of the balls => 10 bis 15 min after total power loss due to its friction and mechanical erection system
Gyro: Stat the advantage of the mechanical erection system (e.g two ball erection system) in case of a standby artifical horizon ?
The mechanical erection system is able to control the gyro's axis as long as the gyro spins
Gyro: Aerobati Adapted Horizon
two bearings on the rear shaft results in an 360 freedom in roll
Gyro: What is teh problem of all two gimbal gyros?
that the outer gimbal may come to a position parallel to the inner gimbal = gimbal lock
Gyro: Controlled precession
to allow 360 move = controlled precession => gyro should indicate 90 nose up or down attitude is forced to turn over 180 degrees by a mechanical blockage which becomes pressed against the outer gimbal shortly before parallel
Gyro: How is gimbal lock inside an artifical horizont avoided in case of unusual altitudes ?
By controlled precession shortly before a gimbal lock could occur
Gyro: Directional gyro
serves as a supplement to the direction finding magnetic compass=> the air needed to drive the gyro (Air in) leaves the gyro housing by two jet nozzles (Air out) => the out streaming air flows at both sides symmetrically against a metal blade
Gyro: What happens when the gyros axis by a Directional Gyro (DG) is not horizontal?
one of the two air streams pushes fully against the metal blade
Gyro: State the number of gimbals of a DG
two
Gyro: State the twp possibilities do powerize a directional gyro?
electrically and pneumatically
Gyro: State the formula for the apparent drift of a DG caused by earth rotation=
15 * cos (a) => The drift of a directional gyro can't be compensated for by an erection system
Gyro: Degree of freedom by the directional gyro?
the DG has two degrees of freedom = the spinning mass is mounted in two independent gimbals
Gyro: Prism Edge by teh DG
Prism edge erection system = that the inner air out flows against the Prism Edge which can be seen above the air holes => gyro not horizontal, the airflow doesn't stream symmetrically against the prism edge and a resulting force occurs
Gyro: Apparent drift caused by rotation of the earth (earth rate)the northern hemisphere?
Indication decreases (-)
Gyro: Apparent drift caused by rotation of the earth (earth rate) southern hemisphere?
Indication increasing (+)
Gyro: Where on earth is the apparent drift of a DG at its max?
at the geographic poles
Gyro: Where on earth is the apparent drift of a DG caused by earth rotation zero?
at the geographic equator
What makes the apparent drift?
caused by rotation of the earth and apparent drift caused by transportation around the earth => the path over the earth will be curved due to the convergence of the meridians
Apparent drift caused by transportation around teh earth: the northern hemisphere:
Indication to the north
Apparent drift caused by transportation around teh earth: the northern hemisphere:
Indication to the south
Behaviour of teh DG Indication (Summarized)
vgl Bild
How is it possible to compensate the apparent dift of a DG
By a compass system
Gyro: What is the task of the set knob which can be found in front of a DG
To adjust the indication of the DG from time to time if no compass system is installed
Gyro:What is the task of a prism edge system inside a DG
It is a pneumatically working erection system
Gyro: At which gimabl position, in relation to teh aircrafts longitudinal axis, is teh gimbal error at its max.?
45 degrees
Gyro: Is the gimbal error a gyro precession error or a gimbal rotation error?
it is a gimbal rotation error
Gyro: A DG equipped aircraft is situated in the northern hemisphere, which indication occurs due to apparent drift caused by earth rotation?
Decreasing indication
Gyro: A DG equipped aircraft is suitated in the southern hemisphere, which indication occurs due to apparent drift caused by earth rotation ?
Increasing Indication
