aclark79 said...
I have never allowed a demonstration of VRS/SWP to develop past a 500 fpm decent rate which would mean that I wasn't in VRS by your definitions.
Out of curiosity when 500 fpm was indicated how long were you stabilized? If your rate of descent was increasing rapidly, and you initiated a go-around at 500 fpm indicated your actual ROD was higher because of the lag in the VSI (unless you have an IVSI).
and now...
Nick swears that VRS can't be established as easily as most of us were taught, and I'm not going to argue with Nick, because he's almost certainly right, and I'm just repeating what I learned from books/instructors which could have been misinformed. It seems that there is an intermediate phenomenon which most of us call VRS or SWP, but some call incipient VRS which exibits the signs and symptoms taught to me as VRS, but without the actual vortex ring. Some have called this overpitching, but I was taught that term referred to a condition where the high pitch / AOA was creating more drag than the engine could overcome leading to a decrease in Nr etc...
Is it possible that while descending at very low, or no airspeed, the fact that we are descending into our own downwash causes such a reduction in angle of attack that we loose a significant amount of lift, even without the development of a vortex ring? (I mean more than just the loss of ETL, but an additional loss of AOA due to descending into air already accelerated by the rotor.) Additionally, in this state, would the addition of some pitch not give us the increase in AOA/lift that we expect, and therefore our rate of descent keeps increasing, and we feel that we are "settling with power"?
I ask because there is definitely a phenomenon when descending at at airspeed less than ETL whereby increased collective pitch seems to have no "bite", no increased lift... and it's quite disconcerting when near the ground.