mercoledì 4 febbraio 2015

New static inverter

To replace my old and small generator, I bought a static inverter able to output pure sine wave 115VAC 400Hz 3 Ph with a rating of 3000VA and an efficiency of 80%; the Input is 28VDC up to 140A.
It should be enough to power all cockpit gauges and computers.
The unit features 3 inverter units which are controlled to have a phase shift of 120° and has an active cooling system provided by internal fan.

Here you can see a video during unit startup and shutdown.

lunedì 26 gennaio 2015

Avionics bending: Flaps Position Indicator

The trailing edge flap position indicating system provides flap position and flap system failure information to the flight deck.
Flap position is indicated by a dial indicator with needles for indicating right and left wing flap and slat position.
The flap position indicator needles are normally driven by the outboard synchro position transmitters in each wing.
The primary source of flap and slat position information is the flap/slat position indicator located on the P3 panel.
The position indicator uses two needles, "L" and "R" to indicate flap and slat position between the 1-unit and the 30-unit positions.
The position indicator shows operation of the slats between the UP and the takeoff position.
When any slat leaves the retracted position the position indicator needles move halfway to the 1-unit mark.
When the slats reach the takeoff position the needles move to the 1-unit position.
Here is SSM reference:

mercoledì 26 novembre 2014

Avionic bending: Rudder Trim Position Indicator


The rudder position indicating system provides the flight crew with the amount of deflection of the rudder surface. This system does not include the rudder trim indication system. For information on the rudder and rudder trim control system

Component Details
Position Transmitter

The rudder position transmitter is mounted below the lower power control actuator. The transmitter's crank is attached to the rudder front spar by adjustable control rod. The position transmitter is clamped to a bracket mounted to a vertical fin rib 
Electrical power to the transmitter is controlled by the RUDDER POS circuit breaker on overhead circuit breaker panel P11.

Position Indicator

The rudder position indicator appears on the lower center display. The indicator scale in each direction is equal to 26 degrees.

The left power bus supplies 28 volts ac to the rotor in the transmitter, which is inductively coupled to the stator. The rotor is mechanically connected to the airplane control surface and rotates with the surface at the same time. Movement of the rudder changes the rotor position which in turn changes the stator output.This output signal is interpreted by computers and displayed on the flight deck. The control surface position is displayed on the lower center display.

The following video shows how the gauge behaves on power up and power down
This other video shows how the indicator behaves using a synchro transmitter moved manually