HELI-90/120/140 refers to a helicopter, with the servos orientated at 90 degrees (2 servos, generally beginner helicopters with forward, back, right, and left movement on the cyclic stick), 120 degrees (3 servos- generally for more advanced helicopters that have collective pitch controls on the rotor blades (yes, this means inverted flight too)), ...
canyon. n. 1. (Physical Geography) a gorge or ravine, esp in North America, usually formed by the down-cutting of a river in a dry area where there is insufficient rainfall to erode the sides of the valley.
A valley is a hollow or surface depression of the earth bounded by hills or mountains, a natural trough in the earth's surface, that slopes down to a stream, lake or the ocean, formed by water and/or ice erosion.Systems of valleys extend through plains, hills, and mountains. valley is a hollow or surface depression of the earth bounded by hills or mountains, a natural trough in the earth's surface, that slopes down to a stream, lake or the ocean, formed by water and/or ice erosion.