capability.
In addition to the standard ESM package, dedicated missile-warning systems are being investigated for installation on the F-22. Historically, 80 % of all aircraft shot down never saw the opponent that killed them. With a missile-warning receiver providing 360deg spherical coverage, a pilot will know when an enemy missile has been fired at him. Based on data from the missile-warning receiver, other aircraft systems could automatically deploy expendable countermeasures (chaff and flares) and sound an aural warning to the pilot. This will improve the pilot's reaction time to an incoming missile, reducing aircraft losses in high-threat environments.
DISPLAYS
Human senses set a limit to how much data pilots can handle before they become overloaded. The key to managing this flood of data is to give the pilot only processed information relevant to the current situation. In other words, we need 'pilot friendly' cockpits: If you don't get the message, it doesn't matter if the computer had the right answer or not. Earlier, we noted the sheer number of gauges, switches, and screens that an early F-15 pilot had to be aware of in order to fly the plane. However, once he went into combat, all he needed to do was put the wide-angle HUD onto the enemy aircraft, which allowed him to keep his eyes out of the cockpit.
The HUD displays all relevant tactical and aircraft-systems information in a clear and concise manner — once you understand what all the numbers and symbols mean. The HUD is tied to and controlled by a series of switches mounted on the engine throttle and control stick. Called Hands On Throttle and Stick (HOTAS), this system allows a pilot to avoid having to go 'head down' into the cockpit while in a combat situation. On the Vietnam-era F-4E Phantom, the pilot had to reach below his seat to find the selector switch for the 20mm cannon! Today, the pilot of an F-15 or F-16 has only to flip a selector switch to control everything from radar modes to weapons selection.
A lot of important data is crammed onto the HUD. For example, a pilot can tell that he is on a course of 191deg at an airspeed of 510 knots, that the aircraft is in a 10deg climb, and that the target is up and to the left of the plane's present course. A short range IR-homing missile can be selected to engage the target, once the pilot is in a proper position to shoot. Unfortunately, when pilots take their eyes off the HUD to look around (and a good pilot will do that often to check his 'six' — the sky behind him), all that data is lost to them until they look forward again. The HUD is just an image projected onto a glass screen mounted above the instrument panel. Since it is a fixed display, it can't follow the pilot's eyes when they look around.
Or can it? Right now, helmet-mounted HUDs are under development in the U.S. and Great Britain (and Israel and Russia both have operational systems). The helmet-mounted HUD supplements the standard HUD, providing enhanced situational awareness. If the aircraft carries air-to-air missiles with slewable seekers (called high off- boresight seekers), like the Russian AA-11 Archer or the Israeli Python-4, the pilot can attack targets that are offset from the aircraft's nose. You can attack a crossing target without wasting time or energy maneuvering for position, which gives you a tremendous advantage in a high-speed, multi-aircraft dogfight or 'furball.'
Future possibilities include virtual-reality (VR) displays, voice-command recognition (remember the book and movie
THE 'EDGE': COMING USAF AIRCRAFT
So what about the 'edge'? What's the next step in combat aircraft design?
Two new combat aircraft will be arriving at USAF bases in the next decade or so; both incorporate elements of the technologies we have talked about. Each is a state-of-the-art solution to some problem that USAF planners identified over the last decade or two, and thus represents the thinking of the late stages of the Cold War. This fact alone has made some folks question their utility and affordability, given the changes in the world scene in the last five years. Nevertheless, given the lessons of the 1991 Persian Gulf War, as well as the general acceptance that the U.S. military in the 21st century will be a 'home-based' force, these systems will be vital to maintaining the credibility of the USAF.
Northrop Grumman B-2A Spirit
Two B-2s, without escorts or tankers, could have performed the same mission as a package of thirty-two strike aircraft, sixteen fighters, twelve air-defense suppression aircraft, and fifteen tankers.
The most expensive airplane ever built is a hard sell to taxpayers and legislators who are increasingly cynical about defense contractors and increasingly skeptical about military procurement. But to understand the B-2, you have to understand the threat that it was designed to overcome and the almost unimaginable mission it was created to perform. One of the things that helped to bankrupt the Soviet Union was an obsessive, forty-year attempt to build an impenetrable air-defense system. The National Air Defense Force (known by its Russian initials, PVO) was a separate service, co-equal with the Soviet Army, Navy, Air Force, and Strategic Rocket Forces. It was designed to keep the U.S. Air Force and the few strategic bombers of the other Western allies from penetrating the Russian heartland and decapitating the highly centralized Soviet command and control system, as well as their top military and political leadership. Ultimately, the only Western plan for defeating the system was the Doomsday scenario, using nuclear missiles to 'roll back' the successive layers of air defense so the bombers could get through to their targets.
In the 1970s, the Russians began to develop mobile ICBM systems that could shuttle around the vast spaces of the Soviet Union on special railroad trains or giant wheeled vehicles. The Soviets knew that every fixed missile silo could be pinpointed by satellite imagery and targeted for destruction; every Soviet ballistic missile submarine could be tracked by sonar arrays and trailed by a U.S./NATO attack boat; but what could you do to kill a mobile missile complex? The proposed U.S. solution was to hunt down the mobile missiles with an aircraft so revolutionary that nothing in the Soviet arsenal could touch it.
An invisible airplane that traveled at the speed of light, armed with precision 'death ray' weapons, would have been ideal. But a subsonic airplane which was almost invisible to radar and IR sensors, carrying a few nuclear-tipped missiles, was sufficient if (and it was a big if) its development could be kept so secret that the other side would have no time, and no data, to develop effective countermeasures. Thus was born the B-2A Spirit. The origins of the B-2 design date back to experimental aircraft of the 1920s, when the visionary Horten brothers of Germany designed their first 'flying wing' aircraft, without conventional tail surfaces and with a cockpit smoothly blended into the thickened wing section. Their goal was low drag (they were unaware as yet of the advantages of a low radar cross section). The problem with all-wing aircraft is that they are inherently less stable than the more normal kind with fuselages and tail sections; and crashes of various prototypes led to the shelving of the Hortens' project (although a very ambitious twin-jet-powered version was under development at the end of the Second
