The other difference, is that in a fixed wing, if the engine coughs and stops momentarily, the windmilling propellor turns the engine over and allows it to fire again.
In an Uptycopter, there is a freewheel unit that does not allow the rotor to drive the engine, so if it coughs and stops, you are on the way down with probably no time to try a restart. You need altitude to establish an autorotation, left hand off the collective, crank the starter switch, with no spare hand to manipulate the throttle, unless you can get the cyclic between your knees. Very unforgiving of fuel contamination, starvation, or poor quality.