Gazelle SA341/342,Avionics, instruments,radio-radar and electro

The torquemeter is an unique instrument but so common at the helicopters.As the word say it measures the torque.Torque between main rotor and engine.It is one of the most important instruments.So here it is at the  test board attached . Then checking the zero point with the test device,it seems ok so far. There you see the fixed zero point ad device prior the testing.                                                                                                                                                                              ...

This is the part of the test flight after C inspection and during the video you will see at 1.25 min the maximum speed of 310 km/h.Enjoy it like I was during the work and  at this beauty and after that at the flight it self. 

Initial remark is vibrating temperature oscillation seen at exhaust temperature indicator at range from 50 to 300 C during the flight.For everyone who knows this type of engine it should be steady at 450 C.The engine RPM are fixed at 43500 which is excellent.The following procedure is check the RPM indicator.Done,  it is accurate.Next is to check the resistance of the wires at thermocouple system.Found to be 18,03 Ohms.Fixed at variable resistor and adjusted it at strictly 16.02 ohms.The serial numbers of thermocouple senders indicated that value. When I have approached the connector and disassemble it I have found that the pins are loose and their connection to the wires are bad. So after carefully inspection there is a one pin with signs of overheating others are too but this one is more than others.Procedure follows.  Changing all four pins by new ones, Coat it carefully with thermo coater insulation , fixing the wires with clamps.Everything i...

Pitot tube is the sender of data for barometric instruments and for many other devices.There is an option at these devices that pressure is converting to voltage through the computer. The pitot tube at Gazelle SA-341,SA-342 will be explained here. Pitot tube is placed just under the cabine and is is collecting P1 pressure which is consisting from mostly dynamic component and slightly from static.Static component is collecting from two holes placed under the gearbox and engine from both sides of the frame. Pitot tube components are : Pressure tube ( 2 ) rilsan, adapter ( 1) holder ( 3) drainage (4 ) montage holder ( 7 ) adapter ( 8 ) Pitot tube with the heater Heater is necessary device and it is preventing pitot tube from freezing at the same time it ensures good air flow during the cold temperatures.It has its own limitation for work.Each manufacturer has its own and it must be at the manual noted. There is a complete scheme for connecting it ...

Avionics in general means all electronic,electric and instrumental equipment that are placed into the airplane or helicopter.Thus it consists from many branches.The first one will be the instruments. Instruments at the airplane or the helicopter are used for measuring and controlling various parameters during the ignition of the engine and during the flight.We can divide them into following groups. Barometric instruments Flight speed indicator,Altitude indicator,Variometer.All of them are powered by air pressure static or dynamic component or both of them. Instruments for controlling the parameters of the engine Engine RPM indicator,Main rotor RPM indicator,various temperature controllers for working temperature of components. Exhaust temperature controller everything is combined with such a fine automatics and is very reliable  indeed.Shaft controllers, torquemeter they are all obliged to give a correct data to the flying crew. Navigation instruments Flig...

Main gearbox is the crucial connection between Astazou engine, frame, the main rotor and tail rotor.This work of tech ingenious art is carrier of the hydro pack as well.There is a RPM sender inside it and you can see rotor rpm-s at the inside scale of tachometer at the instrumental board .At the side of main gearbox is also place for low oil  pressure sender.Everything is here at this video.