Gulf War 20th: Emerging from the Shadows
One of the unforgettable symbols of 1991 was the bizarre-looking F-117A Nighthawk, the world’s first stealth combat aircraft. Looking like something out of a Batman movie, the F-117 seemed born from another world or time. There was some truth in that notion, since the Nighthawk had been built to support new ideas about how air campaigns should be prosecuted. Able to evade most enemy radars and then deliver a pair of laser-guided bombs (LGBs) with pinpoint precision, the F-117 was a “decapitation” weapon. Its mission was to destroy high-value enemy command, control, communications, and intelligence (C3I) targets without requiring or risking large numbers of strike and support aircraft that might suffer losses in heavy anti-air warfare (AAW) environments.
The F-117A did this all and more during Desert Storm. Today, just the movement of F-117s into a troubled region of the world is a signal that America is serious about its commitment, and willing to put the best it has forward. This is an amazing development, especially when you consider that the technology to build the F-117 and other stealth weapons did not even exist at the end of the Vietnam War. The story of the Nighthawk is a tale that tells how a military force moves from an attrition-based strategy to one built on precision as the means of driving an enemy to the negotiation table.
The story of stealth in Desert Storm began in World War II, with the debut of radar in combat. Almost as soon as the British used their chain of home-based radar stations to help defeat the Luftwaffe in the Battle of Britain, the so-called “Wizard War” began. For the next six years, each side strove to counter the other’s radar developments. Out of these efforts came such well-known techniques as radar warning receivers, electronic jamming, and chaff/“window” decoys. All proved useful in degrading the capabilities of enemy radar systems, though they were heavy, expensive, and not suitable for installation into every platform that might need such protection.
This led to various passive efforts to degrade the performance of radar. The most interesting came from German research on radar-absorbent coatings, along with structures and shapes that might deflect the electronic beams. Key among these were the Tarnmatte (camouflage mat) and IG-Jaumann radar absorbent material (RAM) blankets used to hide U-boat snorkels while operating near the surface. There also were some developments in jet-powered flying wing designs by the Gotha Aircraft Company and Horten Brothers, which had very low radar cross section (RCS) profiles. All of these fell into Allied hands at the end of World War II, were examined and analyzed, then quietly put into storage in favor of more obvious technologies of jet propulsion and guided missiles.
The next three decades saw aircraft designers worldwide working to improve the speed, performance and weaponry of combat aircraft, with little thought about their vulnerability to radar detection or guided weapons. Only after heavy losses to radar-controlled anti-aircraft artillery (AAA) and surface-to-air missiles (SAMs) during Vietnam and the 1973 Yom Kippur War were self-protection jammers and decoys made standard equipment on tactical aircraft. Vast amounts of money also began to be spent on development and procurement of radar hunting weapons and aircraft.
The problem was that the Soviet Union and its client states had something new in their defensive bag of tricks: the Integrated Air Defense System (IADS). An IADS is a large centralized data and voice network, with radars, AAA guns, SAMs, and ground-controlled fighters all tied to a primary control center. By the 1970s, the Soviets and their Allies were deploying mobile versions of IADS that could advance with their field armies under a defensive AAW “bubble,” relatively safe from enemy air attack. Thus for good reasons in the mid-1970s U.S. defense officials began to look for technologies that might defeat the IADS and perhaps even radar itself.
Strangely, the beginning of the technology that we today call stealth was to be found in an obscure technical document published in 1962 by a Russian physicist named Pyotr Ufimtsev. His paper, benignly entitled “Method of Edge Waves in the Physical Theory of Diffraction,” was part of a body of work published to describe the behavior of radio waves in real-world situations. In particular, Ufimtsev’s documents laid out the actual mathematical formulas and calculations needed to describe the RCS of a particular object when a radar wave reflected off of it. This clearly was a huge step in the construction of an airframe with a small RCS. Ironically, so obscure was his work that the Soviet government allowed it to be published worldwide!
In 1971, a translator at the U.S. Defense Intelligence Agency saw the document and thought that it might be useful. When the document showed up at the Defense Advanced Research Projects Agency (DARPA), it was realized that Ufimtsev’s calculations might prove useful in the construction of certain types of aircraft and missiles. A small study contract was issued to six aerospace companies, which resulted in the Experimental Survivable Testbed (XST) contract to Lockheed and Northrop. XST was a “paper” airplane contract, with no prototypes being built and the winner having the design judged best. Key to this was a small-scale test model which would be mounted on a pole at a radar test range for testing of its radar return. While the Northrop design was very good, the Lockheed model was almost undetectable. Quickly, Lockheed was given a contract to produce two flying demonstrator aircraft, and the whole program (known as Have Blue) was classified as a “Black” project. In effect, the entire stealth effort, its people, budget, and results, no longer existed to the public or even on the federal budget.
Lockheed’s famous “Skunk Works” was the only manufacturer in the world that had previously built low-observable aircraft from scratch. In the 1950s and ’60s, Lockheed built a whole series of specialized reconnaissance aircraft and drones for the CIA and Air Force, some of which were specifically designed to reduce their vulnerabilities to radar. In particular, the A-12 (the SR-71 Blackbird was developed from this single-seat CIA version) was the first aircraft designed from scratch to minimize its radar signature. Have Blue would take advantage of this earlier effort, in addition to the shaping that could be developed by taking advantage of Ufimtsev’s calculations.
The key to the Lockheed design was based upon shaping, the form of which came from the results of studies developed from Ufimtsev’s formulas. The Skunk Works design team led by Ben Rich (the successor to the legendary Kelly Johnson) decided that a faceted design would give them the best baseline level of stealth against the widest variety of enemy radars. Called the “Hopeless Diamond” by Lockheed engineers, the shape of Have Blue was designed to break up and scatter incoming radar waves, much the way reflective facets of a gemstone or dance hall “disco ball” do. This idea of using shaping to do the majority of the work in a stealth design was radical for its day, previous efforts having been based upon RAS and RAM. In fact, despite some reports to the contrary, the F-117A is built mainly from conventional aircraft aluminum, with very little in the way of exotic materials or composites in the airframe. Now those earlier technologies would be used to fine-tune the Have Blue design and suppress any reflective “hot spots.”
This faceted design points out the real genius of the Skunk Works and the challenges they faced turning Have Blue into a production combat aircraft. The shape of Have Blue was dictated as much by contemporary mid-1970s computer technology as any other factor. Ufimtsev’s equations required a huge amount of processing power to run, and heavily taxed the mainframe and mini-computers of the day. A smooth contour design (like the later B-2A Spirit or F-22A Raptor) would have taken years of computer simulation to design, and Lockheed did theirs in just months. Another problem was that while the Have Blue prototypes had a very low RCS for their time, they could never have flown with a conventional flight control system. Only the development of digital flight control systems in the late 1960s made it possible to make such a shape (essentially a flat-surfaced lifting body) actually fly through the air.
Nevertheless, both Have Blue prototypes were lost due to crashes during testing, though neither loss had anything to do with the basic design. The birds were stealthy and held a lot of promise in the eyes of senior Department of Defense and U.S. Air Force leaders, so the decision was made to move forward. Another “Black” contract was awarded to Lockheed, this time for full-scale development and eventual production of a stealth strike aircraft that would be technically flagged a fighter. It would be armed with passive sensors (no active radar), have only a single pilot, carry all its fuel and weapons internally, and be armed only with precision guided munitions (PGMs) to hit those IADS control centers and other high-value targets at the center of Soviet-style military forces. It would carry no defensive armament, countermeasures, or other system for aerial combat, and would not even have supersonic speed. Its stealth and the planned concept of operations would be its armor against enemy defenses, along with a program of denial, deception, and black-as-a-coal mine security to keep everyone in the world guessing just what it was capable of. Even the plan’s official designation, F-117A Nighthawk, was classified Top Secret until a public unveiling in the late 1980s.
A total of 59 production F-117As would be ordered and delivered, along with the necessary organization and supporting infrastructure needed to make it into a combat warplane. This included building a multi-billion-dollar airbase near the Tonopah Test Range (TTR) in Northern Nevada where they could practice their nocturnal combat routines, and stay as far away from prying eyes and camera lenses as possible. The Air Force also stood up a new combat wing, the 37th Tactical Fighter Wing (TFW) to provide a unit for the new jets to operate within. The 37th was staffed with some of the finest personnel in the entire U.S. Air Force – hand selected volunteers who always grew weak in the knees when they first saw the new “Black Jets.”
New materials, structures, weapons, and other systems had to be developed to meet the objectives for not only a minute RCS (about that of a small bird), but also suppression of infrared, ultraviolet, and other telltale emissions. These new technologies had a vast influence on the stealth designs begun after the F-117A, including the B-2A bomber, the AGM-129 cruise missile, and eventually the F-22A fighter. The JSF designs also owe much of their shapes to stealth design. There even were spin-offs to existing aircraft and missile systems. For example, the F-16C Fighting Falcon and B-1B Lancer both had major reductions in their RCS thanks to minor redesigns of their shapes and applications of small amounts of RAS and RAM. Similar improvements were made to the RGM-84 Harpoon and BGM-109 Tomahawk cruise missiles, greatly improving their survivability in highly defended AAW environments.
First combat use of the F-117 came in December 1989, when the 37th TFW was tasked to launch a precision attack with laser-guided bombs to support a planned special operations “snatch” of Gen. Noriega of Panama in the early stages of Operation Just Cause. While the kidnapping operation was cancelled at the last minute, two F-117s flying non-stop from TTR each delivered a diversionary strike next to a barracks that was to “stun and disorientate” elements of the Panamanian Defense Forces. Press reports later indicated that the Nighthawks had missed their targets, when in fact they had laid the LGBs exactly where planned. The other criticism, that the F-117s had been used as a publicity stunt, was equally inaccurate. The fact was that at the time, the 37th TFW was the only active-duty Air Force unit in the continental United States that was equipped to deliver LGBs. The rest of the Tactical Air Command (TAC) units that might have done the job were in the middle of transitioning to new aircraft and targeting systems, and were thus unavailable.
When Kuwait was invaded in 1990, the 37th was literally in the middle of a command change, with Col. Al Whitley taking over from Col. Tony Tolin. In spite of the command being in transition, the 37th was quickly put on alert to send a squadron of Nighthawks to Saudi Arabia. This was the first large-scale overseas deployment for the F-117, and the world was treated to the incredible sight of 22 of the black jets lined up on a taxiway at Langley AFB, Va. The squadron was getting ready for their trans-Atlantic trip to King Khalid Airbase at Khamis Mushayt, one of the most impressive and isolated of the third-generation airfields constructed by the Royal Saudi Air Force. The fine facilities, combined with excellent support from the U.S. Air Force at home and the local RSAF authorities meant that Whitley and his troops could concentrate on getting ready for the coming air campaign. Their fleet of F-117s eventually grew to a total of 44 in two squadrons and became one of the lynchpins in the planned aerial assault on Iraq.
For over five months, Col. Whitley and his flyers got ready for Desert Storm. Having spent a great deal of effort stateside in development of strike tactics for the F-117, they spent their time refining their tactics and concept of operations (CONOPS) for the coming war. Much effort was spent coordinating with the various intelligence organizations within the U.S. Central Command Air Force (CENTAF) organization, along with high-level national and international sources. Key among these were the “Ravens” (electronic warfare officers) from the 55th Strategic Reconnaissance Wing that flew the RC-135 Rivet Joint electronic surveillance aircraft. Along with other intelligence assets, the RC-135s helped maintain an accurate and up-to-date electronic order of battle of the Iraqi forces in Kuwait and Iraq. This was especially vital to the 37th TFW, because while their F-117s had a very low RCS, they were not invisible to enemy radars. If a F-117 got close enough to a radar of sufficient power and a low enough frequency, then the enemy system might well get a return off of the black jet. Therefore, standard F-117 tactics when flying into defended hostile territory consisted of flying between the known enemy radars and SAM/AAA sites to avoid detection or attack.
At the same time, the 37th pilots had to get fully certified in the use of their navigation, sensor, and weapons systems. Because the F-117′s entire ordinance load is carried internally, and thus limited to just a pair of 2,000 lb. PGMs, it is vital that every bomb count. This meant that the Nighthawk was designed from the start to make use of the new third-generation Paveway III LGBs that were developed by the U.S. Airforce in the 1980s, along with the older Vietnam-era Paveway IIs. To help keep the F-117 from being detected by active sensor emissions, the Nighthawk was equipped with a passive inertial navigation system (INS), as well as a pair of thermal imaging systems. These Forward Looking Infrared systems (FLIRs, one scanning forward and the other downward looking) were used to provide updates to the INS and locate targets during the final bomb runs. These were usually made at medium altitude (12,000 to 18,000 feet), flying straight and level to the target on autopilot. Once in position, the pilot would line up the downward looking FLIR, lock up the desired target, and then the weapons system would automatically drop the weapon. Only then, with the LGB on the way, would a targeting laser fire and “paint” the target for a few seconds to provide the weapon with final guidance.
Assuming the stealth design of the Nighthawk was effective, the first warning the Iraqis would have of an F-117 attack would be the bomb hitting its target. By flying missions only at night and careful route planning, there would be little chance of anything more than random AAA fire being thrown back at the – 117s. That was the theory at least! The Paveway-series LGBs were the finest PGMs in the world in 1991, usually able to hit within 3 meters/10 feet of a well-planned aim point. Even more deadly was the new BLU-109 2,000 lb. penetration warhead, that could be mated to a Paveway guidance kit to create a PGM that could punch through over 3 meters/10 feet of reinforced concrete. Along with the more traditional Mk. 84 2,000 lb. general-purpose bomb warhead, the BLU-109 gave strike planners a formidable array of tools to crack open the critical C3I targets of the Iraqi government and war machine.
All these capabilities made the 44 F-117As of the 37th TFW one of the crown jewels of the CENTAF arsenal. Along with the 66 F-111F Aardvarks of the 48th TFW up the coast at Taif, the 37th made up the whole precision strike force of CENTAF, and for that matter the U.S. Air Force worldwide. If those 110 aircraft could not hit the vital strategic, C3I, and infrastructure targets and destroy them, then Iraq might well win the coming Gulf War. However, the CENTAF staff had laid out an air campaign as smart and innovative as any in history. The entire Iraqi IADS, one of the toughest ever constructed, would be carved up by a team effort by CENTAF aircraft of every variety, along with a few Army attack helicopters. The IADS takedown would take place in a matter of several hours on the first night of the war, and the F–117s would be the lynchpin of the operation. Two waves of 10 Nighthawks each would strike at heavily defended IADS targets and others in the heart of Baghdad itself, the only manned aircraft that would do so throughout the war. If the first few hours went as planned, then the rest of the air campaign would be a virtual cakewalk compared to earlier air wars.
Around Khamis Mushayt, the ground personnel of the 37th worked long and hard to make every one of the Nighthawks ready for combat. The key to the 37th’s operations would be to deliver roughly two dozen sorties a night for the duration of the campaign, something that would tax everyone from the bomb builders in the ordinance shop to the “putty pushers” maintaining the RAM and RAS of the Nighthawk airframes. The intelligence shop had to maintain an up-to-the-minute enemy electronic order-of-battle so that one of the $50 million black jets would not inadvertently run over a newly emplaced SAM or AAA site. All of this was the final push to what had begun in 1971 when the translation of Ufimtsev’s was discovered. In the end, the final exam for the multi-billion dollar project would be up to the young men and women of the 37th TFW, average age about 23 years, trying to put 20 airplanes into the night sky of January 16/17, 1991. It was a typically American story of innovation, hard work, ingenuity, and in the end a well trained team working together. And that first night would tell the tale.
Of course as we all know now, virtually everything associated with the F-117A Nighthawk, the 37th TFW, and the stealth effort went perfectly during Desert Storm. The -117s did everything asked of them and more. Al Whitley and his pilots ranged across Iraq for the duration of Desert Storm without so much as a single scratch being inflicted by Iraqi defenses on the black jets. Night after night, the F-117 drivers went into the night skies, earning the nickname of Shaba (Arabic for “Ghost”) for their feats of precision bombing. Along with the F-111s of the 48th TFW, they destroyed almost every important target American intelligence could identify. When the war was over, the performance of the Nighthawk was seen, as a validation of stealth for every important aircraft program in the U.S. Air Force’s future. While the end of the Soviet Union and the Cold War made such grand plans financially impossible, new stealth aircraft are still being produced based upon those basic equations of Pyotr Ufimtsev that the Soviets did not think were important enough to classify. Stealth is a powerful Cold War-era legacy which is still paying dividends in the 21st century, and represents one of the most important advances since the dawn of warfare.
This article was first published Desert Shield/Desert Storm: The 10th Anniversary of the Gulf War.