In late April, the Mil Mi-171A2 flying testbed completed the second phase of the preliminary flying tests at the Moscow Mil Plant to checking the multirole medium helicopter’s readiness for additional certification tests.
The testbed performed a total of 67 ground runs and 72 flights, which confirmed that the helicopter’s performance meets the design parameters.
The second phase tested the Klimov VK-2500PS-03 engines, as well as the modified stabilizer and tail-rotor pylon. The rotor system was also tested.
The first phase tested the new main rotor blades made of polymers and composites, the X-shaped tail rotor, improved rotorhubs and swashplate, and also the 8M reinforced transmission. The first phase included 43 flights, which demonstrated lower main rotor vibrations, an increase in the main rotor thrust of more than 800 kg, and improved stability thanks to the new tail rotor.
The next testing phase will involve tethered trials to test the compliance of the rotor drive system and actuators with the requirements of the AP-29 aviation rules.
The first Mi-171A2 prototype is also going through tests. By the beginning of May, this airframe had performed 42 of the 178 planned flights. A second prototype is in the final phase of completion. It will incorporate all the structural improvements to be incorporated in future production helicopters.
The Mi-171A2 is the latest in the Mi-8/17 family of medium helicopters. It features the KBO-17 digital avionics suite developed by the Ulyanovsk Instrument Manufacturing Design Bureau. The KBO-17 eliminates the need for a flight engineer, bringing down the crew headcount to two.