Some thoughts:
The effects of tractor/trailor, direction of rotation, and wind into tail rotor all limit the maximum thrust that a given tail rotor can produce. All these factors serve as excuses for design teams once the tail rotor is determined to be marginal, none are reasons for it to be marginal, because it could/should have been made large enough to produce the required thrust, regardless of its details. That is why Pprune Fan #1 said, "A noted helicopter authority (and renowned teetotaler) Sir Nicholas of Lappos maintains that it doesn't matter as long as the tail rotor itself is stout enough." Saying that a tail rotor has poor performance because it (insert one-) is on the left/right, rotates the wrong way, has main wake impingement) is like saying after your ear was bleeding because you picked it with a nail, "I hate when that happens!" In other words, no matter what the basic design features, it could have the required thrust, if you built up some other feature(s). If the direction of rototion will rob some thrust, just make the rotor a bit larger, or have it spin a bit faster, or build in some more pitch range.
A tail rotor that blows its high velocity wind onto a close surface is slightly less efficient that one that blows away from the fin.
A tail rotor that spins so its bottom blade moves toward the main rotor is slightly more powerful than otherwise.
A tail rotor that receives some main rotor wake during high thrust operations will produce slightly less thrust than otherwise.
A tail rotor that is too small will become inadequate if any of the above are also true. It could have been made larger, and we would not discuss how any of the above was a factor, because only when it is too marginal to begin with do we discover the small aerodynamic effect that drives it over the edge.
For this reason, LTE is the product of inadequate tail thrust, not a mysterious aerodynamic problem that swamps healthy tail rotors. That is why it affects only one type of helicopter.
And last, but not least, I am not a tea-totaler, in spite of SASless's misdirected assertions otherwise. Should any Ppruner come past Stratford CT, I would be glad to conduct a demonstration to prove this fact (at the expense of the doubter, of course!)
