Quoted from sbmania:OP-
Thanks for the insight into helos. I know nothing about helos but once upon a time did some flying in gliders. While I am well familiar with stalling a fixed wing aircraft, I had no idea that one could stall a helicopter. How does that happen exactly? I thought if the pitch was at a certain point and the engine speed was sufficient, the helicopter goes up? How do you stall a helo and how do you recover from it?
On another note, when autorotating in the event of engine failure, do you need forward airspeed to autorotate or just altitude?
Finally, does a helicopter have the type of instrumentation that would show the pilot "which way is up" if he gets into heavy fog and loses sight of the horizon, similar to the instruments fixed wing aircraft would have? Thanks!
Since you are familiar with stalling a wing then this may be easier to grasp. There's low speed stall and high speed stall in airplanes. A helicopter stall (Vortex ring state/settling with power) is the equivalent of a high speed stall. Too much blade pitch even though you still have airflow over the blade(wing). The blade stops flying(no more lift generated). The descent rate would likely be much higher than 2000'/min however. This may have happened but it usually only happens in low speed/high rate of descent conditions which helicopter pilots are trained to avoid. You can also stall a helicopter by flying too fast but that would cause the nose to rise sharply and reduce your airspeed thereby negating the condition that caused that stall in the first place.
You can autorotate with zero or near-zero speed and you can auto-rotate with airspeed. Depends on what you are trying to do (max glide distance, min glide distance, min rate of descent, etc). Zero speed autorotation is less forgiving for pilot mistakes and you have to pick up some speed for the flare/landing otherwise it would be impossible or nearly impossible to stop the rate of descent.
A large helicopter like the S-76 most likely have instruments and be IFR certified (certified to fly on instruments). The OP mentioned they are a VFR only operation so I'm not sure on how much instrumentation it would have but at a minimum it would most definitely have an artificial horizon (the black/white ball) and other basic instruments. The biggest issue isn't the instrumentation but having the pilot recognize that he is disoriented and switching to instruments. It's much harder than anyone thinks. Your body/brain is telling you something different than what is really happening. It's a crazy feeling that can't be well reproduced in simulators or explained in a forum...
For the record I'm a military helicopter pilot (Bell 212/412) that had an extreme vertigo episode in a low vis situation in the early days of my career. I was able to maintain control with great difficulty and concentration but I advised my crew of what I was going through so that the PIC could keep an eye on my handling just in case. Worst experience of my life that ended up being the best lesson learned in my life.
