Originally Posted by
stilton
I understand that in limiting conditions of density altitude / heavy weight a helicopter can use a rolling take off rather than a vertical one
My question is how this works, particularly in reference to control inputs
Do you start the roll with a little forward cyclic and full up collective, lifting into the air when enough lift has been achieved or start with a little forward cyclic, full down collective and slowly bring the collective up as you gain speed and lift off ?
Additional questions, will you have achieved translational lift before lifting off ? Is this necessary?
Do helicopter manufacturers endorse and or certify their aircraft for this generally and do they provide recommended flight manual techniques ?
Do I have this correct in when you might use this type of take off ?
Finally would you ever perform a run on landing for similar reasons ?
Fixed wing pilot here, trying to understand this ( rare ?) aspect of helicopter flying
We performed rolling takeoffs in the UH-60. They were conducted when the aircraft was incapable of hovering due to the combination of GWt and density altitude.
Generally speaking, the takeoff was performed by coordinating collective increase with forward cyclic to achieve the quickest possible acceleration. Upon reaching a preplanned airspeed (above ETL, respecting GS limits), maximum collective was applied for the climb out. Many additional techniques were employed to enhance safety margins.
Since there were no flight manual procedures or performance charts supporting the maneuver, methods were developed to determine a takeoff speed and predict when OEI capability would be achieved. Until then, a powered-descent and run-on landing was the only option in the event of an engine failure.
A run-on landing is also the accepted procedure for OEI conditions and other emergencies.