I'll try again.
the technique given in the FAA handbook. "If the prerotator is capable of spinning the rotor in excess of normal flight r.p.m., the stored energy may be used to enhance short-field performance. Once maximum rotor r.p.m. is attained, disengage the rotor drive, release the brakes, and apply power. As airspeed and rotor r.p.m. increase, apply additional power until full power is achieved. While remaining on the ground, accelerate the gyroplane to a speed just prior to VX. At that point, tilt the disk aft and increase the blade pitch to the normal in-flight setting. The climb should be at a speed just under VX until rotor r.p.m. has dropped to normal flight r.p.m. or the obstruction has been cleared. When the obstruction is no longer a factor, increase the airspeed to VY."
This technique is not possible in any gyroplane I know about.
First, it requires the ability to change collective pitch. from spin-up to flight. There are only two models sold the to the public that can do this, the J-2 and the A&S18A. I have substantial experience with both, and neither can permit this technique.
For the McCulloch J-2, one can pre-spin to 125% of flight rpm before starting the take-off roll. However, when you disengage the rotor drive, you also automatically go to full flight pitch at the same time (the same control disengages the transmission, releases tension on the belt drive clutch, and lifts the swash plate to flight collective position.). The take-off run is done at full throttle, while the rotor rpm
decays (that's why you spin to 125%, so that you have a margin to allow for that decay). Anything less than full throttle lengthens the run and costs more rpm, seriously impeding take-off performance. There is no additional power to be added, and the blades are already in flight pitch, so this procedure is impossible.
For the A&S18A, you can prespin to 150% of flight rpm to store energy before any take-off roll. After disengaging the rotor drive, the blades must be kept in flat pitch during the run to minimize rpm
loss (again, there is no increase in rpm possible). The run is done at full throttle, so there is no power to be added (again, less than full throttle will eat distance and cost rpm, so it's a stupid idea). When you choose to leave the ground, you
DO NOT tilt the disc aft (the manual suggests putting the stick aft/left but that's only an inch of stick displacement to anticipate pitching/rolling after leaving the ground). You push a button on the throttle that releases the blades to
take-off pitch (about double normal flight pitch). As you rise, coning causes the blade pitch to reduce to the normal flight value through pitch-cone coupling via the delta-three hinging. The departure from the ground is in a level attitude. For short fields, typically one pushes the button to leave the ground at about 45 (Vx is 50) but
immediately establishes Vx to hold until the obstacle is cleared (the manual says "climb at best angle"). Rotor rpm will be down to the flight value in the blink of an eye (you will be nowhere near the obstacle when that happens) so that bit about holding just under Vx until one or the other is nonsense.
I think the author of this piece read the 18A manual, but didn't understand it, and has never seen the aircraft in operation, much less served as PIC.