Technical system Flashcards
What is APU?
Auxilluery power Unit. its purpose is to bleed air for engine start and provide pnematic power start the engine one by one and environmental control system (ECS) when it is on the ground.
How does APU starts?
Electronic sequence unit will draw 28 DC V from battery which is under the co-pilot seat. The start signal from ESU sends 28V DC to the APU hydraulic start valve. Turning hydraulic start valve on releases the accumulator hydraulic charge. This charge will start starter motor and rotates the APU compressor and the fuel pump while ESU monitor the starting sequences to 100% controlling ignition and signals fuel pump to open.
How does APU get recharged?
APU Accumulator (Hand Pump is also used to recharge accumulator hand pump) provides hydraulic pressure to the APU starter (min is 2,650psi). When AC Power is available, accumulator is charged by the backup hydraulic pump. The AC generator of APU will turn on when the APU is in operation. AC generator of APU provides power for the helicopter system and the backup hydraulic pump.
Can you explain about Engine?
We have T700 engines. The engine is a front drive turbo shaft engine and it has 6 stages compressor, annular combustion chamber, 2 stages of gas turbine and 2 stages of power turbine. Assessory module has Enhanced digital electrical control unit) which is a brain of engine that control HMU for fuel scheduling, it govern TGT, Np and Torque matching between 2 engines. It has got 4 modules cold module, hot module, power turbine and assessory module.
In cold module, it has got inlet which sucks the air through 12 swel vanes and 18 de swel vanes that is to seperate the dirty air particles through IPB blower into scroll case. De swel vanes is also to provide stready air flow to 6 stages of compressors. The air will go through first 2 stages which is
What is Load demand Spindle (LDS) and Power Available Spindle (PAS)?
LDS receives signals from HMU according to pilot’s collective and pitch control inputs to control engine speed and provide required power. Note: LDS is near the mixing unit.
PAS receives signals from pilot operated Power Control Levers (PCLs) that adjusts performance according to stage of flight (OFF/IDLE/FLY/LOCKOUT)
What is the purpose of hydraulics?
The purpose of hydraulics is to power flight controls and other systems (electrical and mechanical) to reduce workload on pilot.
How many Hyd pumps do we have?
A total of 4 hyd pumps. 3 of them are identical and one utility pump for sonar reeling machine.
What are the functions of hydraulic pump 1, 2 and backup?
Hydraulic pump 1 goes through the No.1 Transfer Module and provides power to the first stage of primary servos (F,A,L) and first stage of T/R servo.
Hydraulic pump 2 goes through the No.2 Transfer Module and povides power to the pilot assist servos (C,P,R,Y) and second stage of primary servo.
Backup Hydraulic pump goes through utility module and provides hydraulic to transfer module 1 and 2 rescue hoist and APU accumulator.
Utility Pump: This independently provides hydraulic fluid to the sonar reeling machine (ALFS).
What are the additions to these pumps?
There is also a LDI (Leak Detection Indicator) where it tries to maintain hydraulic pressure to primary and tail rotor servos , should malfunction occur.
This is achieved through 2 logic modules in order to isolate the leak.
Where does hydraulic leak test is enabled and disable?
Its enabled on the ground and disable in flight from WOW switch.
What is Stabilator is?
The variable angle of incidence stabilator enhences handling qualities in the pitch axis in forward flight.
SCALP
1.Streamlines with rotor downwash at low speed (below 30 knts) to minimise nose up attitude from downwarsh.
- Collective coupling to min. pitch attitude excrusions due to collective inputs.
- Angle of incidence decreases above 30 kts to improve static stability.
- Lateral Sideslip to pitrch coupling to reduce susceptibility to gusts
- Pitch rate feedback to improve stability.
