bar's internal slider to slotted plates in the drift bar and ground speed slider translate the motion of the wind bar into components along and across the axis of the drift bar. Motion across the axis pushes the entire wind bar to the left or right, indicating the proper heading to fly to cancel out the wind drift. Motion along the axis pushes the ground speed slider fore or aft, accounting for the difference between air and ground speed. The ground speed slider also carries the pin-shaped foresights, so as they move they adjust the sighting angle in order to drop the bombs early or late to account for the ground speed. The motion of the wind bar and wind screw knob accounts for two of the three vectors involved in the windage calculation. The last is the airspeed of the bomber – its absolute direction can be ignored if everything is measured in terms of the direction to the target, as in the case of the CSBS. The length of this vector is set by the air speed drum, found on the right side of the main case (or at the back of the device on earlier versions). Turning the air speed knob that pushes the tube carrying the wind direction shaft fore or aft. A housing at the end of this tube carries the wind bar, so rotating the airspeed drum moves the entire wind speed calculation fore and aft to account for increasing or decreasing airspeed. Once set, the combination of the air speed, wind direction and wind speed provided all of the vector inputs, and the angle of the drift bar and position of the foresight formed the output. The drift wires running down either side of the drift bar were used to measure the drift once calculated, to ensure the aircraft was flying along the correct heading to zero out any wind drift. The bombsight solution is now almost complete, having calculated the ground speed and zeroed out any sideways drift. All that is left is the calculation of the time of fall, which, multiplied by the ground speed, gives the range. The CSBS solves this through the height bar, which extends vertically from the center of the device where the compass section meets the drift bar. Turning a knob at the top of the height bar (or using a slip fitting on earlier models)