5351T

5351T radiator in the 5349T oil cooling assembly

The 5351T is an aircraft air-oil radiator used in the oil cooling system of Mi-8 family helicopters and related modifications. The item is installed as part of the larger 5349T radiator configuration, which consists of separate radiator sections. In this arrangement, the 5351T represents the upper radiator section, while the 5350T is associated with the lower section. For catalog, supply, and maintenance purposes, the product is usually identified simply as radiator 5351T, without adding “upper part” to the product name. The radiator may be supplied in left-hand or right-hand execution, depending on the required aircraft installation side.

Oil cooling function of the 5351T radiator

The 5351T supports heat exchange in the helicopter lubrication system by transferring excess heat from oil to the airflow passing through the radiator core. During operation, lubricating oil must remain within the required temperature range to preserve correct viscosity and protect loaded assemblies. The radiator helps reduce thermal stress in the oil system and supports stable operation of engine and transmission components. On Mi-8 type helicopters, this is important during ground running, hover, climb, cruise flight, and operation in hot ambient conditions, where oil temperature and airflow through the cooling system may change significantly.

5351T as a section of the 5349T radiator configuration

The 5351T should be understood as one radiator section within the complete 5349T cooling configuration. The full 5349T radiator arrangement includes upper and lower elements that together provide the necessary cooling surface and oil flow capacity for the helicopter system. This means that the 5351T must be selected according to the aircraft parts catalog, radiator assembly layout, installation side, and actual aircraft configuration. When ordering the part, it is important to confirm whether the requirement is for the 5351T radiator only, the related 5350T section, or a complete 5349T radiator set.

Left and right executions of the 5351T radiator

The 5351T radiator may be supplied in left-hand and right-hand versions. These versions are normally mirror-type executions intended for installation on opposite sides of the aircraft cooling system. The left and right radiators may differ in connection layout, mounting geometry, fitting orientation, airflow path, and installation arrangement. For this reason, side identification must be confirmed before procurement. In technical correspondence and commercial offers, it is useful to specify the required execution clearly: 5351T left-hand or 5351T right-hand, depending on the aircraft configuration and the customer’s installation requirement.

System integration of 5351T in Mi-8 oil circuits

In the helicopter system, the 5351T works together with oil lines, mounting elements, airflow ducts, thermostatic or bypass components, and the remaining section of the 5349T radiator arrangement. The radiator must provide stable oil passage and effective heat transfer while remaining leak-tight under vibration, pressure variation, and temperature changes. Before installation, the core and collectors should be checked for contamination, corrosion, deformation, blocked passages, damaged fins, and signs of previous leakage. Since the 5351T forms part of a larger cooling system, its condition affects the total cooling efficiency of the engine and gearbox oil circuits.

Identification and supply of radiator 5351T

The product is identified by the designation 5351T. In Russian-language documentation and supply requests, the designation may also appear as 5351Т or 53-51Т. The radiator should be verified against the aircraft documentation before supply or installation, especially where left and right executions are involved. Depending on availability and customer requirements, the item may be supplied as new, serviceable, overhauled, or from storage. For correct procurement, the request should state the designation, required side, condition, documentation requirements, and whether the item is needed separately or as part of a larger 5349T radiator configuration.

Product Type: Aircraft air-oil radiator / radiator section
Designation: 5351T
Alternative Designations: 5351Т, 53-51Т
Function: Cooling of lubricating oil in helicopter oil cooling systems
Application / Where Used: Helicopter engine and main gearbox oil cooling systems
System / Installation Area: Part of the 5349T air-oil radiator configuration
Compatible Aircraft / Equipment: Mi-8, Mi-17, Mi-171, Mi-172 helicopters depending on configuration
Available Executions: Left-hand and right-hand versions
Execution Type: Mirror-type left / right configuration depending on installation side
Radiator Arrangement: Upper section of the 5349T radiator assembly
Associated Lower Section: 5350T
Associated Complete Assembly: 5349T / VMR 5349T
Working Fluid: Lubricating oil
Cooling Principle: Heat exchange between lubricating oil and ambient airflow
Material: Aluminum collectors and core
Estimated Weight: Approx. 9.2 kg per unit
Weight Basis: Approx. 60% of complete 5349T radiator weight of 15.4 kg
Interchangeability / Compatibility: To be confirmed by aircraft parts catalog and radiator assembly documentation
Technical Documentation: Product passport and operational documentation

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Warranty
All products are covered by a standard 6-month warranty.
Extended warranty is available upon request and is agreed individually; it may affect the final product price.