In the animation movie "Planes 2" we see the helicopter (Blade character) performing first a 180° roll (getting inverted chassis up and rotor down) and then the U-shaped half loop down into the normal orientation. From Wikipedia it looks like the Split-S.
Are helicopters actually capable of doing this? The concerns are
- An inverted wing still may provide a lift upwards, but the inverted rotor will pull downward. Hence the inverted orientation seems risky.
- Wings provide air support while making the sharp U-turn. Can the helicopter rotor do the same?
If a helicopter would manage this figure, would it trade altitude to speed as the fixed wing planes do?
If the model is important, the helicopter looks somewhat like Augusta Westland.