NP-103-2

Hydraulic power generation by NP-103-2

The NP-103-2 has a fixed displacement and non-variable delivery. This means the pump geometry is set by design, and the flow rate changes mainly with shaft speed. As the drive shaft rotates, the axial piston group creates suction and discharge cycles, drawing hydraulic fluid from the inlet line and delivering it to the pressure line. The pump is designed for nominal discharge pressure of 195 kgf/cm², with maximum discharge pressure of 210 ±5 kgf/cm². These parameters place the NP-103-2 among high-pressure aircraft hydraulic units.

Installation of NP-103-2 on the engine accessory gearbox

The NP-103-2 is mounted on the aircraft engine accessory gearbox / drive gearbox by a flange connection. The pump does not have its own electric motor. It receives mechanical torque through a splined drive shaft connected with the engine gearbox drive. Because of this installation, correct operation depends on the pump itself and on the condition of the drive interface. During installation, the mounting flange, centering surfaces, splines, shaft seal area and connected hydraulic lines must be checked carefully.

NP-103-2 in Tu-22M2 / Tu-22M3 hydraulic systems

The NP-103-2 is used on Tu-22M2 and Tu-22M3 long-range supersonic bomber aircraft. It is installed on the accessory drive gearbox of the NK-25 turbojet engine and works as one of the main sources of high hydraulic pressure. The pump supplies AMG-10 hydraulic fluid to aircraft hydraulic circuits that operate heavy control and mechanical systems. On this aircraft class, stable hydraulic pressure is essential because many key systems are hydraulically powered and work under high loads.

Hydraulic consumers supplied by NP-103-2

The NP-103-2 can supply pressure to several major onboard hydraulic consumers. These include flight-control actuators, rudder and spoiler drive units, landing gear extension / retraction mechanisms, wheel turning and braking units, pressure accumulators and wing variable-sweep mechanisms. On Tu-22M aircraft, the pump is associated with hydraulic equipment that supports wing sweep change, flight-control stabilization and landing gear operation. The exact distribution depends on the aircraft hydraulic system layout and should be checked by aircraft documentation.

Inlet boost and drain requirements of NP-103-2

The NP-103-2 requires positive inlet pressure in the range of 2–5 kgf/cm². This means the hydraulic system must provide forced feed to the pump inlet, usually through a pressurized hydraulic tank or boost supply arrangement. The pump also has a drain line. Internal leakage used for lubrication and cooling is removed through a separate drain fitting and returned to the tank. The drain line is important because blocked drainage or excessive leakage can damage shaft seals and affect pump reliability.

NP-103-2 design and connection points

The NP-103-2 has a compact cylindrical body with a round mounting flange, splined drive shaft and threaded hydraulic fittings. The pump normally includes three main connection points: inlet, high-pressure outlet and drain. The flange has centering surfaces and mounting holes for attachment to the engine gearbox. Because the pump works at high pressure, the condition of fittings, sealing rings, flange surfaces and drain path is important during maintenance. Any leakage or contamination may affect the hydraulic system and nearby engine components.

Supply and related NP-103 series pumps

The NP-103 family includes related versions such as NP-103 and NP-103A. The base NP-103 was historically used on the Tu-144, while NP-103A is associated with MiG-29 applications in KSA-2 and KSA-3 accessory gearbox systems. These versions should not be considered automatically interchangeable with NP-103-2. For procurement, the exact designation, required rotation direction, working fluid, aircraft type and documentation must be confirmed. Before installation, the pump should be checked by hydraulic parameters, leakage, drive condition and passport records.