Setting the enemy speed screw or enemy direction knob moved a mechanism similar to the wind bar, but the movement along the track moved the entire height bar fore or aft. Notes References Citations Bibliography See Appendix C, Section VII Further reading An image of the Mk. IX mounted in a Mosquito can be found in Ian Thirsk, "De Havilland Mosquito: An Illustrated History", MBI Publishing Company, 2006, p. 68 External links Optical bombsights Weapons and ammunition introduced in 1917