The bomb aimer viewed through the optics (eyepiece absent) to pick out the target and try to keep the target in a fixed position on the cross hairs. The optics were connected to a gyroscope mounted in gimbals, which kept the optics level when the bomber rolled or pitched.
Flight controls of the bomber were handed over to the bomb-aimer as the bombing run began. He corrected for drift and yaw through the controls.
He set height (on a scale) and speed (adjust speed of a universal DC motor) in a mechanical computer elsewhere in the bomb aiming apparatus. The computer controlled the forward tilt position of the optics via a thin wire.
When the computer determined that the correct bombing position had been reached, a contact was closed, which triggered bomb release.
