To: Bert Sousa
I stated the following on another thread about taking off from an elevated deck. I think the situation might be similar relative to the rotor dynamics.
Being a theorist and not a pilot I open myself to some flack on this but I will repeat what I stated in a post I made a long time ago. This post is in response to the advice given about hovering the helicopter to the edge of the flight deck placing half of the disc in ground effect and the other half out of ground effect.
The UH-60 was hovering over an inclined surface and facing into the rising ground. This placed the forward edge of the disc over the higher surface and the opposite edge of the disc was over the declining surface. This could have caused an imbalance of the downward airflow causing a variance in the lift (ground effect) being generated across the disc. This imbalance could have forced the helicopter backwards and in the process it tried to maintain its' relative position to the declining ground surface thus sliding backward and downward while airborne. If the pilot tried to compensate for this backward movement he may have caused the nose to drop and the imbalance of the ground effect was exacerbated increasing the rearward movement. At least it is a theory.
