Differential Synchros

8/10/2019 Differential Synchros

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Synchronous Data-Transmission

Systems


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Introduction

As part of the technique of Remote Indicating,

synchronous data-transmission systems, or synchrosystems as they are generically known, were

introduced.

Synchros consists of transmitting and receiving

elements which, in varying circuit configurations, are

now utilized not only in certain engine instruments,

but also in analogue-type ADC, remote-indicating

compasses and in flight director systems for headingand aircraft attitude sensing.


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Categories of Synchro systems

Four main categories

Torque

Control

Resolver

Differential


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In some applications its necessary to detect

and transmit error signal representative of

two angular positions and in such a manner

that the receiver element of a synchro system

will indicate the algebraic difference or the

sum of two angles.

Differential synchros


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TDX synchro system


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3. Differential synchros

Used to find the error difference between two

angular positions

Differential synchros when utilised in torque

or control synchro system, they are designatedas TDX and CDX respectively.

Rotor Rotation

Clockwise rotation taken as positive Anticlockwise rotationtakes as negative


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Algebraic Addition


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CDX synchro system


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3. Resolver synchros

Used to convert

voltages which represent the cartesian

coordinates into polar coordinates

Also from polar coordinates to cartesian

coordinates


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Polar and Cartesian coordinates


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Polar to Cartesian Coordinates


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Cartesian to Polar Coordinates


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ANGLE OF ATTACK SENSOR


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Wing assumes a stalled conditions.Since it

occurs at a particular angle rather than a

particular speed,the critical AOA is also

referred to as the stalling angle.

Angle relates to the design of aerofoil adopted

for wings for any aircraft varies between 12

and 18 .

AOA sensing


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AOA is measured with respect to airflow.

SWS computer: incoming data from from the

AOA sensor is processed and compared with

the allowable stall limit angle which is one or

two degrees below the critical stall angle.

The limit angle is computed by taking the

inputs such as flap position, pitching rate and

bank angle.


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At the critical AOA ,the wing is unable to

support the weight of aircraft causing the

aircraft to descend,which in turn cause the

AOA to increase further.This is known as stall.

Stall condition is very dangerous particularly

at low level flight altitude.


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Stall warning system

Simplest and adopted in several types of smallaircraft consists of a hinged vane type sensor

mounted in the leading edge of a wing so that

the vane protrudes into the airstream. The stall warning system gives warning about

the incipient stall condition,by alerting the

pilot even before stall conditions are reached.


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Stall warning system typically comprises of

1.AOA sensor

2.SWS computer 3.Warning indicators

-stick shaker

-aural warning -stick pusher

STALL WARNING SYSTEM


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STALL WARNING SYSTEM

STICK SHAKER SYSTEM

Differential Synchros

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