I think I saw that Russian technique described somewhere along the line.
The technique may be incomprehensible to some PhD's because a coherent, linear-thinking approach may fail to derive theory supporting it. It may be a technique that uses bits of disjoint theory and perhaps some assumptions that aren't generally supportable, but works most of the time and/or perhaps all of the time in most real-world cases -- one of which may be tail rotors.
I led an R&D team that developed a self-balancing washing machine some years ago. Interesting problem because of severe cost constraints of the whitegoods market and ill-defined boundary conditions. Example: consumer washers are never bolted to concrete, and some set on the flimsy floor of a doublewide. The structure was comprised of stamped sheetmetal and some plastic, certainly not cast iron like machine tools or tire balancing machines. There were a shitload of resonances, and many of them weren't very predictable. In addition, this washer went much faster than traditional washers in the spin cycle, because it could self-balance. That reduced energy necessary for drying. Barely-damp clothes peeled off the drum with pronouced dimples in them.
The team used a technique using oversensing and SVD (singular value decomposition) sometimes used in aerospace guidance & control systems. It worked! At least a dozen patents were spawned.
Then politics and corporate infighting rendered the project stillborne.