If the boom angle remains the same while telescoping in, what happens to the boom radius?

When the boom angle remains constant while the telescoping of the boom occurs, the boom radius decreases. This is due to the mechanics of how a telescoping boom operates. As the sections of the boom are extended in or out, the point of reach from the center of rotation shortens if the angle does not change.

When telescoping in, the effective length of the boom from the pivot point to the end of the boom becomes shorter, which results in a smaller radius. The radius is determined by the distance from the center of the crane's rotation to the hook or lifting point, and if the boom is telescoped in while keeping the angle the same, this distance diminishes. Hence, the boom radius decreases as the sections of the boom are drawn in closer together.