5349T Set

Cooling function of the 5349T left and right radiators

The 5349T radiator set provides heat dissipation by transferring heat from lubricating oil to the ambient airflow passing through each radiator core. Oil enters the radiator sections from the helicopter lubrication system, passes through the internal tube structure, releases heat through the core and collectors, and returns to the oil circuit at a lower temperature. The paired left-right configuration allows the system to distribute cooling capacity across both sides of the aircraft installation. This is important during ground running, hover, climb, cruise flight, hot-weather operation, and other modes where thermal load and airflow conditions can change.

5349T dual-section design in each radiator unit

Each radiator in the 5349T set is configured as a dual-section heat exchanger with independent oil circuits. One section is intended for engine oil cooling, while the second section is used for main gearbox oil cooling. This design allows each radiator unit to support two separate lubrication systems without mixing their working fluids. The arrangement is practical for Mi-8 type helicopters, where the cooling system must remain compact but still provide reliable thermal support for the powerplant and transmission. Each radiator has its own cooling surfaces, tube groups, and oil capacities for the engine and gearbox circuits.

Left and right 5349T installation as a matched set

The 5349T set consists of two radiators: left and right. Side identification is important because each radiator is installed according to its mounting position, connection layout, airflow path, ducting arrangement, and system geometry. When both units are supplied as a set, the installation can restore the paired cooling configuration of the helicopter oil system rather than replacing only one side. This can be relevant during overhaul, modernization, major maintenance, or replacement of older radiator types. Before installation, the left and right units should be checked against the parts catalog and the actual aircraft configuration.

System integration of the 5349T radiator set

In the helicopter system, the 5349T radiator set works together with oil pumps, pressure and return lines, thermostatic elements, bypass channels, temperature monitoring equipment, and airflow ducts. Both radiators must maintain stable oil flow, withstand operating pressure, and remain leak-tight under vibration, temperature changes, and varying flight loads. The internal oil passages should be clean, while the external core area must allow free airflow for efficient heat exchange. Blocked passages, crushed fins, contamination, corrosion, or leakage in either radiator can reduce the total cooling efficiency of the system and lead to abnormal oil temperature behavior.

Identification and interchangeability of the 5349T set

The radiator set may be identified under the designations 5349T and VMR 5349T. It may also be referenced as an analog or interchangeable option for radiator 2281B / VMR 2281B, depending on aircraft documentation and installed system configuration. This interchangeability should not be assumed by designation alone, because left-right configuration, connection points, mounting geometry, oil circuit routing, and approved documentation must be verified. When ordering the set, it is important to specify that the requirement is for the complete left and right set, including condition, documentation, completeness, and applicability to the target helicopter.