Reading all those war books taught me some helicopter terminology, like "translational lift." Simply put, when a helo is moving slowly, the main rotor's downwash creates vortexes and general turbulence immediately around it.
Its translational lift begins at 15 knots, and there's a northeasterly, 10-knot wind.
With the helo pad on uneven terrain, it was clear they'd fly out of ground effect during departure--before they got much help from effective
translational lift (ETL).
* LT Benjamin Armstrong, USN, "Reaching
Translational Lift: The History of the Helicopter and Lessons for 21st Century Technology" (http://www.airpower.maxwell.af .mil/airchronicles/cc/armstrong.html)
"The aircraft was in what they call
translational lift, meaning it had lifted off and was headed out of the helipad and then it went down.
Potentially high winds, paired with a venturi effect between the ships, may have caused some weathervaning and loss of
translational lift during the forward transition.
The climb began to pick up as I felt the aircraft go through
translational lift. OK, things were beginning to make sense again; all was returning to normal, although painfully slow.
We didn't waste a single bit of forward momentum in our quest to reach
translational lift before slamming back into the runway.
I already was in an accelerating attitude, so I maintained cyclic position and cracked collective, hoping
translational lift would take affect before Nr and altitude ran out.
The strong winds out of the north definitely helped keep us in
translational lift, and we started an air taxi.
