3top said:
c) "Slamming down the collective!" This is a no-no!!
Slamming/snapping down the collective does nothing good - it will only get you towards a low-g situation (which in an auto is not as bad as in a regular push-over, but....).
All you will do is go nearly through the roof!
Correct action is to lower the collective SMOOTH and QUICK, but please don't slam it. Give the rotor some time to change the airflow!
back to b) The faster you fly when 0-power hits, the faster Nr will decay. Worse yet the faster you fly the more inertia the helicopter will have (the whole machine, NOT the blades!), which means it will not want to really start to decend, but keep going straight (I think that Newton-guy found that out some time ago...)
Hmmm. I think Newton might have been thinking
slightly differently.
What you interpret as low "G" when you rapidly lower collective is in fact only that the helicopter starts down before you do. Lowering the collective won't cause the helicopter to experience any significant low "g". In the R22 the blades do not go into negative pitch with a full-down collective, so the airframe will continue to pull down on the disk. More importantly, if the helicopter is accellerating downward rapidly enough to make you feel light in the seat, the airflow is also more rapidly reversing.
This is one significant difference between dropping the collective and a cyclic pushover. Believe me, the faster you get the collective down, the less Nr decay you will have.
Next, the rate at which Nr decays is directly related to the amount of blade pitch being pulled just before the power goes away. This is only somewhat related to airspeed - if you are in a 500'/min rate of descent at 70kt, Nr will decay much less. But I'm splitting hairs on this one.
However, the rate that an object FALLS is not affected by its horizontal velocity. A bullet shot from a gun over a level surface will hit the ground at the same time as another bullet dropped simultaniously from the same height (aerodynamic effects aside). Inertia is relative to velocity, but velocity is a vector quantity, so
in the vertical plane, a helicopter at 70kt has no more inertia than a helicopter at 0kt.