BlenderPilot,
The stuff you were taught about the factors that cause VRS are correct, because they all affect the downwash speed, which directly affects the VRS condition.
Power required to hover is prime. As the weight grows, you need more power (and more downwash) to support the machine. Remember that Bernoulli is interesting, but it is the stream of air you are blowing downward that makes the lift to hold you up. More weight means more downwash velocity, so the VRS rate of descent actually increases slightly.
In your case with the 206, what was your approximate weight? How much maximum torque did you have available (as compared to the 80% you needed to hover)? What was your maximum available vertical rate of climb?
I published a web page that explains this, and I used a 3,500 lb Bell 206 at 8,000 feet for the example. See this pointer:
http://mywebpages.comcast.net/llappos/
I hope this helps explain things.
SASless I added some discussion of what probably happens in many cases when a pilot falls through on approach. I believe that this is what happened to that legendary Sea King. I recall that the machine was spinning right as it descended, probably because the pilot had drooped the rotor to try to hold the OGE hover, and he ran out of pedal. This is appears to be a classic case of "Settling with too little power" and not settling with power (as in VRS).
Regarding the old legend that in VRS more collective makes you go down faster, I don't think that is correct. More likely, if you are in VRS, the collective doesn't do much, and that is disconcerting enough. If you increase collective, you could droop the rotor rpm, and that would be a bad thing, as well.
In truth, real VRS is hard to get into, and hard to stay in. In a powerful helicopter, you can actually muscle your way out by just increasing collective (I was told that the test pilots in the Sky Crane when flying with no load could just climb up out of VRS). This is not true of any working helicopter, so it is not recommended for recovering.
Note from the chart that you can clean up the VRS flow entirely by DESCENDING faster until you get out of VRS, and into autorotation. I have done this countless times in an S-76 during testing. It is a bad idea if the ground is within 2000 feet or so, since the rate of descent gets to 4000 to 6000 feet per minute, a truly sporty fall!
The best cure for VRS is to nudge yourself forward to gain the forward velocity to clean things up, in a jet ranger, by 12 knots you are entirely out of it.
There are two big reasons for making a point out of this distinction:
1) If you try to hover with too little power, that is a chargable foul and indicates poor planning and headwork. This is too common, and is too easy to prevent. To call it VRS allows too easy of an excuse for the pilot.
2) The VRS accident for the V-22 was classic, full blown VRS, and was increased by simply back tilting the nacelles. In tests after the accident, crews were able to induce VRS in LEVEL flight, no descent, while back tilting the nacelles (so much for pilot error, huh?) If we in the helicopter world toss about the definition of VRS improperly, someone in tilt rotor land will say that VRS is common, and such incidents in a tilt rotor are "just like helicopters" so why all the fuss.
Nick