Mi-8T re-engining solution

The Ukrainian engine maker Motor Sich is offering its new TV3-117VMA-SBM1V Series 4E turboshaft (also known as TV3-117VMA-SBM4V) as a re-engining option for Mil Mi-8T helicopters. The earlier TV2-117 version installed on these rotorcraft is too underpowered for unrestricted operations in mountainous regions.

The TV3-117VMA-SBM4E is derived from the TV3-117VMA-SBM1V design, another product independently developed by Motor Sich (the TV3-117 baseline was designed at Klimov). The -4E engine features an electric starter system and a gearbox-mounted generator.

Says Nikolay Zubko, director of the Motor Sich helicopter division: "What makes the TV3-117VMA-SBM4E an optimal powerplant choice for the Mi-8T is the lubricated main gearbox freewheel. This is the principal difference of the VR-8 gearbox from the one used on the Mi-17 helicopter, and is the necessary minimum for making the new engine suitable for Mi-8T installation."

A series of tests held in Feodosia, Ukraine in 2011 revealed that the re-engined Mi-8MSB version demonstrates performance close to that of the Mi-8MT. Zubko says the TV2-117-powered Mi-8T has a maximum operating altitude of 4,500 m. The Mi-8MSB, for its part, has climbed to 6,300 m. In terms of maximum operating altitude it has already overtaken the Mi-17 with its 5,000 m and is closing in on the latest VK-2500-powered Mi-17V-5 modification (6,400 m). Motor Sich says the Mi-8MSB will be priced several times lower than the Mi-17.