Descending from Altitude
O-Downwash
If a helicopter descends straight down in still air, it will likely fly into its own
down-wash as illustrated in Fig. 6-10. This is like flying into a strong downdraft and
the helicopter will drop rapidly even at full power.
The technical term for this situation is “descending vortex-ring state”. Pilots of
full-size helicopters refer to it as “settling with power” (although it is very unsettling to
most pilots). If you are ever caught in this situation, immediately fly forward or
sideways to exit the down-wash or you will soon hit the ground.
Another way to avoid settling with power is to fly in circles during descents. It is easier
to judge forward speed when viewing the model from the side while it is circling rather
than from the front when it is coming straight at you.
When decending from altitude, you will notice that substantial forward cyclic
pressure is required to maintain speed in a descent. This is due to the decreased
effectiveness of the cyclic controls as rotor speed is reduced (a characteristic of all
fixed-pitch rotor systems).
Landing
Landings can be a source of tail boom strikes for beginning helicopter pilots.
Helicopter flyers with airplane experience sometimes unconsciously pull back on the
fore-aft cyclic stick as their helicopter nears the ground as though they are controlling
the elevator on an airplane. This tilts the helicopter backward.
Op er a tor's Guide
Learning to Fly
LITE MA CHINES
6-11
Figure 6-10.
