NR-30AR

Fuel supply function of the NR-30AR pump-regulator

The main task of the NR-30AR is to deliver aviation fuel to the combustion chamber at the required pressure and in the required quantity. The pump section generates fuel pressure, while the regulating section meters fuel according to engine operating mode. Correct dosing is especially important during engine start, acceleration, throttle movement and operation at altitude. If the fuel flow is too low, the engine may not reach the required mode. If it is too high, temperature, speed or combustion stability limits may be exceeded.

Automatic fuel metering by the NR-30AR

The NR-30AR automatically meters fuel throughout the operating range of the engine. It works with the pilot’s throttle lever command and hydromechanical feedback from the engine. The unit helps maintain rotor speed and adjusts fuel delivery when external flight conditions change. This is important for stable operation of the D-30 engine at takeoff, cruise and idle power settings. The regulator also participates in limiting maximum engine parameters, protecting the engine from overspeed, overheating and abnormal fuel scheduling.

Axial plunger pumping unit in the NR-30AR

The NR-30AR uses an axial plunger pumping section with variable delivery. Fuel delivery is controlled by changing the position of the pumping mechanism, including the swash plate angle according to the operating mode and regulation schedule. This design allows the unit to develop the pressure required for fuel supply to the nozzle circuit while maintaining controlled metering. Because the pump-regulator contains precision plunger and spool elements, clean fuel, correct filtration and proper inlet conditions are critical for reliable operation.

Start and acceleration control by the NR-30AR

During engine start, the NR-30AR provides a strictly metered fuel schedule while the rotor is being accelerated by the starter. This helps support ignition without overfueling the combustion chamber. During acceleration, the unit increases fuel delivery according to a programmed schedule, preventing surge, overheating and unstable operation. These functions are handled by the starting / acceleration automatic section and the centrifugal speed regulator. Proper adjustment of these sections is normally checked on a dedicated fuel-control test bench.

Reverse-thrust and correction functions of NR-30AR

The NR-30AR includes functional sections that can support reverse-thrust operation and correction of fuel-control parameters depending on D-30 engine version. For D-30 Series II engines installed on Tu-134A aircraft, the unit may interact with reverse-thrust control logic and hydromechanical blocking elements. It can also work with correction devices and actuators such as IMT-3 type equipment depending on engine configuration. These interfaces must be checked by the engine documentation, since details may differ between D-30 variants.

Working fuel and operating conditions of NR-30AR

The NR-30AR operates with aviation kerosene grades TS-1, RT and T-1 according to GOST 10227-86. The fuel-control system must provide clean fuel and correct inlet conditions to avoid unstable metering or damage to precision internal parts. The unit is designed to operate across aircraft flight conditions, including high-altitude operation and low ambient temperatures. Fuel contamination, air in the line, poor filtration, incorrect adjustment or worn internal pairs can cause difficult starting, unstable idle, slow acceleration or failure to reach selected power.

Supply, repair and inspection of NR-30AR

For procurement or repair, the full designation NR-30AR / НР-30АР should be used. The unit may be supplied new, from storage, repaired, overhauled or bench-tested depending on availability. Since the NR-30AR is a fuel-control unit, visual inspection is not enough. Before installation, it should be checked for drive interface condition, housing integrity, fuel port cleanliness, seals, corrosion, preservation state, adjustment points and documentation. Bench testing should confirm delivery, pressure, starting schedule, acceleration behavior, speed regulation and limiting functions.