Originally Posted by
helispotter
A final observation: In one of the Hill Helicopters videos on the HX50, Jason Hill makes mention of the use of what I would call a 'fence' fitted to the horizontal stabilizer just outboard of the tail boom and indicates this is all about improvement of the flow characteristics over the stabilizer (or words to that effect). It seems complicated to me, but I haven't seen the CFD analysis they have no doubt undertaken to come up with this detail. Still, it is surely a less draggy stabilizer implementation than what is now on Bell 505, R44 and R66?
I have doubts that anybody understand the flow patern on the tail of a rotorcraft. You got the induced flow from the main rotor, posssibly the interacting flow from the tail rotor, and then the forward air flow. That sounds like a big wirlwind shake to me, Hills and the HX50 treat it with aerodynamics principle akin to a high performance glidder, well I buy don't it. last time I heard, CFD on a rotor system is still a developing science due to the complexity of the flow interaction between blades (tip vortices) all that in a moving frame of reference.
The proof that nobody has understood anything is all these new horizontal stabilizer evolutions/modification, the H160 being a visible effort in that field.
The R66 just got it from the R44 that got it from the R22, I think you would be chocked to see how little thought went into it.