Pod and boom

From RC Helicopter Wiki

Pod and boom models form the majority of model helicopters used. They consist of a 'pod' – the main body of the helicopter, containing the engine, flight electronics, fuel tank, etc, all covered by a canopy; and a 'boom', on the other end of which is the tail rotor.

Pod and boom models are used for a number for reasons. They are lighter than they would be if they had an enclosing skin, they are easier to work on, and there is less to break in a crash. Pod and boom models are easy to convert into a scale model; typically the mechanics are simply installed into a suitably-sized scale fuselage.