5349T Right

5349T right air-oil radiator in helicopter cooling systems

The 5349T is an aircraft air-oil radiator used in helicopter oil cooling systems. This version represents the right-side radiator unit within the paired cooling arrangement of Mi-8 family helicopters and related modifications. The radiator is designed to remove heat from lubricating oil circulating through the engine and main gearbox systems. During helicopter operation, it supports stable thermal conditions for assemblies working under constant load, including engine components, transmission units, bearings, gears, and shafts. Correct operation of the 5349T helps keep oil temperature and viscosity within the required operating range.

Oil cooling function of the 5349T radiator

The 5349T provides heat dissipation by transferring heat from lubricating oil to the ambient airflow passing through the radiator core. Oil enters the radiator from the helicopter oil system, passes through the internal tube structure, releases part of its heat through the core and collectors, and returns to the lubrication circuit at a lower temperature. This process is required during different operating modes, including engine start, warm-up, ground running, hover, climb, cruise flight, and operation in high ambient temperatures. Stable cooling helps prevent oil overheating and supports reliable operation of the engine and main gearbox.

5349T dual-section design for engine and gearbox oil

The 5349T is configured as a dual-section heat exchanger with independent oil circuits. One section is intended for engine oil cooling, while the other section is used for main gearbox oil cooling. This design allows the radiator to serve two separate lubrication systems without mixing their working fluids. For Mi-8 type helicopters, this arrangement is practical because the cooling system must remain compact while supporting both the powerplant and transmission. Each section has its own cooling surface, tube group, and oil capacity, corresponding to the thermal load of the specific circuit.

Right-side installation of the 5349T radiator

This version of the 5349T is supplied as the right radiator unit. Installation side is important because the left and right units may differ by connection layout, mounting points, ducting arrangement, airflow direction, and installation geometry. For replacement or procurement, the required side should be confirmed before order placement. The part should be matched against the aircraft parts catalog, maintenance documentation, and the actual helicopter configuration. This is especially important for aircraft that have undergone overhaul, modernization, replacement of previous radiator versions, or changes in oil cooling system layout.

System integration of 5349T with helicopter oil circuits

In the helicopter system, the 5349T works together with oil pumps, pressure lines, return lines, thermostatic components, bypass channels, and temperature monitoring equipment. The radiator must maintain stable oil flow, withstand operating pressure, and remain leak-tight under vibration and temperature changes. Its internal passages must be clean, while the external core must allow free airflow for effective heat exchange. Blocked passages, crushed fins, contamination, corrosion, or leakage can reduce cooling efficiency and lead to abnormal oil temperature during flight or ground operation. Proper inspection is therefore important before installation.

Identification and interchangeability of 5349T / VMR 5349T

The radiator may be identified as 5349T or VMR 5349T. It may also be referenced as an analog or interchangeable item for radiator 2281B / VMR 2281B, depending on the aircraft documentation and installed configuration. This interchangeability should not be assumed by designation alone, because installation side, fittings, mounting geometry, oil circuit arrangement, and approved documentation must be checked. When ordering, the required position, aircraft type, condition, completeness, and documentation should be stated clearly. Aviation supply should include a product passport and operational documentation confirming applicability and technical status.

Product Type: Aircraft air-oil radiator / heat exchanger
Designation: 5349T
Alternative Designations: VMR 5349T, ВМР 5349Т
Function: Cooling of engine and main gearbox lubrication oil
Application / Where Used: Helicopter oil cooling systems
System / Installation Area: Engine and main gearbox lubrication systems
Compatible Aircraft / Equipment: Mi-8, Mi-17, Mi-171, Mi-172 helicopters
Configuration: Dual-section radiator for engine oil and gearbox oil circuits
Position: Right radiator unit
Working Fluid: Lubricating oil
Cooling Surface, Engine Section: Approx. 2.76 m²
Cooling Surface, Gearbox Section: Approx. 1.84 m²
Number of Tubes, Engine Section: 12
Number of Tubes, Gearbox Section: 18
Maximum Oil Pressure at Inlet: Approx. 2 kgf/cm²
Thermostat Spring Setting Pressure: Approx. 2.5 kgf/cm²
Maximum Oil Temperature at Inlet: Up to +120 °C
Thermal Valve Activation Temperature: 65 ± 5 °C
Capacity, Engine Section: 2.2 ± 0.2 L
Capacity, Gearbox Section: 1.5 ± 0.2 L
Material: Aluminum collectors and core
Dimensions: Approx. 800 × 710 × 160 mm
Weight: Approx. 15.4 kg
Interchangeability: Analog / interchangeable reference for 2281B, VMR 2281B depending on aircraft documentation
Technical Documentation: Product passport and operational documentation

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