NickLappos writes…
AnFI, there really is no such thing as Vx for a helicopter. There are families of angles available, depending on the speed you chose to get to, and there is a distance needed to accelerate to that speed, which changes the resultant achieved angle. This entire complex thing is simplified by providing one speed, one angle and one solution known to work.
In addition, some Manufacturers offer selectable OEI Vtoss in the 40-60 knot range and provide performance charts that give climb angle as a function of weight, altitude, air temperature, headwind, and Vtoss. When these charts are combined with takeoff distance charts and takeoff site geometry, obstacle clearance can be determined during pre-flight planning for PC1 operations, thereby accounting for the variables mentioned above.