As a full scale helo pilot, here is some info. Even when a full scale helo does loops and rolls, it never experiences a negative "g" load. If you do, the rotor flexs down and cuts off your tail. Not a good thing. Also, in a UH-1 Huey, at 326 rpm on the main rotor, there is about 100,000 lbs! pulling out on the blades. That is where the strength comes from. And as one who has been shot down at least 35 times flying full scale drone helo's, as the rotor rpm decays due to an engine failure, the blades"cone" upward and lose rigidity. No, the super Cobra can not hover inverted, and as I mentioned above, you do not do negative g stuff, even with the most modern helos. Hope this helps a bit. Also, a loaded Huey will not lift off in a hover here in the desert when the density altitude is really high. You slide off forward until about 13 knots when the aircraft goes into translational lift, and the horsepower required for flight is quite a bit less. Some people don't realize you can roll, loop, etc, and still pull positive g's.