Fighter Combat

FIGHTER WEAPONS 13cause large, erratic pipper movements during this settling time, makingthe sight unusable.You can have computer sights or anything you like, but I think you have to goto the enemy on the shortest distance and knock him down from point-blankrange. You'll get him from in close. At long distance, it's questionable.Colonel Erich "Bubi" Hartmann, GAPWorld's Leading Ace, Luftwaffe352 Victories, WW-IIA significant advancement in gunsight technology was the addition ofautomatic ranging information, usually provided by radar. Early systemsused a fixed radar beam, with fairly wide-angle coverage, centered directlyahead of the fighter. Whenever a target (or anything else) was placed withinits field of view and range coverage (usually on the order of one mile), thisrange-only radar would measure the distance to the target, indicate therange through the sight system, and send values of range and range rate tothe gunsight computer. Radar-measured range and range-rate informationis ordinarily much more accurate and smoother than manual input. In caseof a radar malfunction, manual backup might be possible, or the computermight simply assume some nominal range and range rate.Radar is discussed in much greater detail later in this chapter, but two ofits limitations can be mentioned now in connection with gunsights. Oneof the problems with most designs is encountered when the radar islooking down at low altitudes, where "ground return" might obscurereturn from a relatively small target and render the radar ranging unusable.In addition, radars are susceptible to a wide variety of electronic countermeasures(ECM). Figure 1-3 is an illustration of a typical radar LCOSdisplay.A gunsight that causes the pipper to move around within the sight fieldof view (as opposed to a fixed sight) in response to the maneuvers of theshooter aircraft is sometimes referred to as a "disturbed-reticle" system.Within this broad category there are many variations. The type of LCOSwhich has been described attempts to predict the position of the target(LOS and range) at one TOP in the future and then displays a pipper thatdirects the pilot in providing the proper amount of lead. This type is knownas a "director" or "predictor" sight. Besides all these difficult predictions,the accuracy of this system is also dependent on the target maintaining afairly constant maneuver (the closer to a straight line at constant speed, thebetter) for at least one TOP after the prediction is completed.Another mechanization of the disturbed-reticle LCOS might be called a"historical" or "real-time" sight. This system only predicts the bullettrajectory and "remembers" this trajectory until its TOP would be complete.It then displays a pipper that represents the point of impact of thatbullet on a geometric plane at the target's present range. Such a gunsighttells the shooter what is happening at the present time to bullets fired oneTOP in the past, thus the term historical. If the pipper is superimposed onthe target, bullets should be passing through the target if the shooter wasfiring one TOP earlier.