Originally Posted by GregoryV022

depends on the helicopter. i fly remote control ones in my free time. bigger helicopters, the 12 to 30 degrees maybe sounds about right. but for small ones, depending of design and purpose, can go 90 degrees and back again. but of course they would have to be very high off the ground because at 90 degrees, all lift is lost. some pilots have modified the rotor trim control on the helicopter to enable it to fly upside down. So practically anything is possible