The Zhukovsky National Research Center has developed an unusual aircraft scheme with an electric or hybrid propulsion system. The main feature is two double-row pulling propellers at the wingtips, each of which is driven by two independent engines.
In total, the propulsion system has 4 engines. If one engine fails, the automation system shuts down the working engine located symmetrically on the opposite wing. As a result, the thrust on both sides of the aircraft remains more uniform, and the dangerous yawing moment is reduced.
This scheme solves the main problem of wingtip engines, where an engine failure far from the longitudinal axis creates a large yaw moment. The patent states that disabling the paired engine reduces this effect and maintains aircraft controllability.
At the same time, the designers retain the aerodynamic advantage of propellers at the wingtips. They rotate in the opposite direction to the wingtip vortices, which should reduce induced drag. The designers estimate a potential gain in aerodynamic efficiency of up to 10–20% compared to a conventional scheme without wingtip propellers.
The electric version uses 4 electric motors. In the hybrid version, there are 2 internal combustion engines and 2 electric motors, and the failure of one internal combustion engine is also compensated by the automatic shutdown of the symmetrical electric motor.