Excellent book that compares and contrasts Lockheed and Northrop’s approaches to developing Stealth. Well grounded in the academic literature yet admirably concise and readable. Fully engages written sources and combines this with extensive interviews. ( )

My expectations going into this work were tempered in regards to how much the author could really say about this program; the answer turns out to be a lot. Westwick did not approach this topic from a dead start, having been involved in a long-term project to document the social history of aviation in California. This means that he can place the development of stealth into the context of the history of the Lockheed and Northrup companies. It also means that Westwick appreciates what a program like this meant to the people who worked at these companies on these high-risk, high-reward projects. There was also a great deal of coverage of the basic science involved in making stealth work. Finally, Westwick was fortunate to get access to many of the participants before they pass on, meaning that this history should have some real staying power. Best grace note in the book: Jack Northrup received a technical briefing on the B-2 bomber before it broke cover, and before he passed away, thus receiving validation for his belief in the flying-wing platform. ( )

In "Skunk Works," Ben Rich gave his recollections on the development of stealth warplanes at Lockheed. "Stealth" gives a slightly broader perspective on the story, covering the competition between Lockheed and Northrop. It has at least as many funny anecdotes and factoids. The narrator is a bit more remote, there is some repetition, but it is still an interesting and readable story. Westwick actually goes into more technical detail on a number of points, clarifying Rich's story.

> on the one hand, the sharply angular [Lockheed] F-117; on the other, the smoothly rounded [Northrop] B-2. … In a fantastically fertile five-year period in the mid- to late 1970s, engineers at the two firms arrived at different solutions to achieve the same breakthrough: aircraft essentially invisible to radar

> The primary approach to detect incoming aircraft, involving giant concrete acoustic mirrors, could at best pick up bombers at 15 miles

> No sweat … until American planes started dropping from the skies over North Vietnam. Soviet-made SA-2s decimated American planes at high altitudes, and when the US shifted to low-altitude raids, shoulder-fired SA-7s proved surprisingly effective. Electronic countermeasures helped but often required support aircraft to fly alongside; over North Vietnam, the US averaged a ratio of four radar-jamming aircraft to every strike aircraft. … The 1973 Arab-Israeli War confirmed the lesson, as Soviet-built radar systems dealt high losses to the Israeli Air Force, downing over a hundred aircraft in eighteen days.

> The CIA could simply aim radar receivers at the moon to pick up the reflected signals from Soviet early-warning antennas. These data, supplemented by spy planes carrying radar receivers, mapped the location and strength of the Tall Kings

> The radar equation states that the cross section varies with the fourth power of the distance. Say that a Soviet early-warning radar could pick up an American aircraft at 200 miles, which gave the Soviets twenty minutes to alert their antiaircraft missile batteries and scramble interceptors. Cutting the detection distance in half, to 100 miles, required cutting the radar signature not by 2 but by 2^4, or 16

> If the surface has straight edges, the radar waves bounce back perpendicularly, as if from a mirror, so you get a spike, like a glint of light, in one direction. If the surface has curved edges, you get a smaller return but in all directions. The Lockheed and Northrop philosophy was that it was better to have one single spike and then make that spike go the wrong way, away from the radar antenna. The McDonnell Douglas approach was to avoid a spike altogether and scatter the reflection in many directions.

> add cesium salt to the jet fuel; the cesium ionized the exhaust gas, creating a plasma plume to absorb radar and shield the exhaust ducts. Thus, although the A-12 and SR-71 included some radar-reducing features, the design was dictated primarily by aerodynamics, and most of the radar reduction came from materials

> Ufimtsev’s breakthrough was to separate the surface currents into uniform and nonuniform components. The uniform current was the same as that expected on a flat surface by standard physical optics. The nonuniform current was what appeared at irregularities in the surface: edges, tips, cracks, or curves. Ufimtsev called these nonuniform components “fringe currents,” since they appeared along the edges of bodies. By showing how to calculate the fringe currents and the radiation they generated, he accounted for the diffracted waves in the missing region. He published his theory in a 1962 report—in Russian, of course—whose title translated as “Method of Edge Waves in the Physical Theory of Diffraction.” … Even after Ufimtsev and his institute tried applying the theory to airplanes, in effect pursuing the concept of Stealth, the Soviet military showed no interest. On the contrary, they met outright resistance. The aircraft design bureaus insisted that aircraft design was a matter of aerodynamics, not electromagnetism—and that aeronautical engineers, not physicists, designed planes. Thus the aircraft designers’ standard response to Ufimtsev: “Go away.” … Ufimtsev, for his part, shrugged and returned to his equations. He was completely unaware that his theory had sparked a revolution in the other camp.

> Locus was in the habit of browsing translated Soviet journals. He ran across an article by Ufimtsev that seemed interesting and urged Northrop’s resident diffraction theorist, Kenneth Mitzner, to read it. … Ufimtsev’s nonuniform currents filled the crucial gap in existing theory about radar scattering. No American scientist had ever met him, but the Soviet physicist, known only as a name and theory, became a legendary figure in Stealth design rooms. Northrop’s team liked to interrupt their work with choruses of “Go Ufimtsev!” to the tune of “On, Wisconsin!” … To the US intelligence community, meanwhile, Ufimtsev’s name became equally mythical, but as a source of concern. They already knew that Soviet physicists and mathematicians were top-notch. Here was a crucial advance made in 1962, and the US only translated it in 1971. The Soviets had about a decade’s head start.

> Stan Locus had the simple inspiration to drive a nail into the model on the test stand. If the radar reached the nail, it would reflect and light up like a beacon on the radar screen. When the nail showed up on the radar, they pried it out and hammered it in again, this time a bit farther back around the curve; when they reached the point where it didn’t show up on radar, they knew how well that particular curve performed.

> The pole had to get the model high enough off the desert floor to avoid backscatter from the ground; it was originally made of Styrofoam, a nonconducting surface that scattered few radar waves. A crucial problem was that both Lockheed and Northrop’s airplane models promised cross sections far below what RATSCAT or any other test range could measure. Substantial effort thus went into improving test ranges, to lower the background radar clutter to the point where the test range radars could measure the model cross sections. In particular the Styrofoam pole reflected far more radar than the model, so Lockheed supplied a stealthy pole

> Groundwater could affect the radar tests: Scherrer once recorded scattering from a target over the course of an entire day and found that it varied by several decibels, which he eventually traced to the tidal rise and fall of the underground water table.

> For some of them, however, the main competition was not the Soviets but rather their engineering colleagues at the other firm. As Cashen put it, “It’s just like we were playing with the best in the Super Bowl every year.”

> The full-scale models were made of either plywood or foam and fiberglass, coated with conductive silver paint to mimic the radar behavior of a metal plane. … During one test Lockheed’s radar signature bloomed by about 50 percent. It turned out a flock of birds had lit on Lockheed’s model and proceeded to do what birds do, and the bird turds blew up the signature. … The tests used four-tenths scale models, but those models were still big: four-tenths of the Northrop design’s wingspan was still almost 70 feet. The sheer weight of Northrop’s model on the pole was causing it to flex, creating tiny cracks in the paint. The web of cracked paint was reflecting the radar and thus blowing up the signature.

> the 7/16-inch ball bearing that Lockheed engineers rolled across briefing tables represented only the cross section of their XST design when viewed nose-on and level and for a particular radar frequency.

> Generally, big early warning systems like the Tall Kings used lower frequency, while antiaircraft radars used higher frequencies to provide the resolution needed for precise tracking and targeting

> if an antiaircraft radar saw a plane from the side, the plane would be moving too fast to track. So that left the front and the back. Damaskos’s formula defined the nose and tail sectors as anything within 45 degrees of the airplane’s centerline, either forward or aft … Northrop immediately protested. Radar would light up most attacking aircraft, speeding toward enemy territory, from the front. Northrop’s engineers had thus designed their plane assuming a wider radar threat in the front, 60 degrees from centerline, or a 120-degree wedge in all. They similarly assumed that radar hitting the back of the plane was a lower priority, since that meant the airplane was speeding away from the antiaircraft site and therefore presented a harder target to hit. So for the rear of the plane Northrop designed around a zone only 35 degrees from centerline, meaning a 70-degree wedge.

> To save money the Skunk Works had skimped on Have Blue’s brakes, and the first plane had a drag chute to help it slow down. Nevertheless, at the end of every rollout after landing, the ground crew found the brakes were literally red-hot and glowing. The crew had to station big fans at the end of the runway and run them out to the plane to cool off the brakes before they caught fire.

> The committee’s report, entitled Discriminate Deterrence, urged that the US military make Stealth a top priority, touting its potential, in combination with precision-guided munitions, to replace nuclear weapons.

> Two parallel edges essentially provided a single radar spike in the same direction, the same as would reflect from a single edge. So the Northrop team embraced what they called parallel planforming. A simple, boxy airplane with parallel edges—in the fuselage, the wings, and the nose and tail—would produce just a handful of spikes. BSAX, in fact, was a six-spike airplane. … the importance for Stealth of parallel planforming—that is, having aligned edges in the planform—and of minimizing the number of parallel edges, each of which produced a radar spike. A flying wing, since it lacked fuselage or tail, minimized the number of spikes.

> Northrop managers made a remarkable gamble: they told DARPA they refused to enter a competition. They had been working on the assumption that they had the job, and they protested that the government was now threatening to give it to Lockheed. Northrop calculated that the government didn’t want Lockheed to have a monopoly on Stealth, so the firm in effect said: if you don’t give us the job, we walk. And that would mean Northrop was out of the Stealth business, leaving Lockheed with a monopoly and the government with no leverage on future projects. The gambit worked. DARPA backed down and in April 1978 gave Northrop a sole-source contract for Tacit Blue.

> “So the RCS [radar-cross-section] guys would always say, ‘We want Gaussian curves.’ And our configurator, the guy who did all the layout of all the lines, said, ‘Well, they think they’re getting a Gaussian, but the shop can’t make it, and they’re getting conics.’” That, of course, did not satisfy the RCS guys. Mitzner fired off a memo insisting that Northrop’s lofters get up to date

> Like Lockheed’s Skunk Works, Northrop benefited from an integration of design and manufacturing. For Tacit Blue, aircraft design and production were in the same place, in Building 360 in Northrop’s Hawthorne plant.

> When Northrop engineers rolled Tacit Blue out of the hangar at Area 51, some Lockheed engineers watching the exercise were bemused. One asked, “When are you going to take it out of the crate?” Tacit Blue looked like an upside-down bathtub. Its ungainly appearance and bulbous nose, offset by the flaring V-tails that looked like flukes, earned it the nickname “the Whale.” As a counterpart to the skunk logo of the Skunk Works, Northrop staff took to sporting a whale logo. … Tacit Blue didn’t just look odd. It also flew funny. It was totally unstable in yaw, tending to swing around like a weather vane and end up flying tail first. It was also unstable in pitch: if it departed more than about 6 degrees from level flight it would flip over on its back. That earned it another nickname, “HUM,” for Highly Unstable Mother. To tame Tacit Blue, Northrop designers turned to flight controls, having learned from their mistake on XST, when they neglected to include fly-by-wire.

> to save money, instead of adding seals around the cockpit door, so that radar beams wouldn’t reflect off the gap, Northrop engineers just used conducting tape—like aluminum duct tape. After the pilot climbed into place, the flight crew would tape him in

> Democrats had long opposed the B-1, and they backed the Stealth bomber as a way to justify that opposition without being seen as “soft on defense.” Republicans continued to support the B-1 as the safest bet, leading Washington wags to joke that the B-1 was a Republican plane and the Stealth bomber a Democratic one.

> if the New York Stock Exchange believed that Northrop was withholding material information from stockholders and the market, it would delist the company. He alerted the Defense Department, which sent a lawyer to talk to the leaders of the stock exchange, explaining that national security meant there could be no public comment. The stock exchange replied, in effect, “Fine, Northrop can choose not to reveal the information, and we will just delist the firm.” Jones persuaded Pentagon officials to craft a press release that addressed the stock exchange’s basic question—did Northrop have a contract or not?—without revealing what the contract was for.

> Tacit Blue gave Northrop three crucial advantages in the B-2 contest. First, it was on Tacit Blue that Northrop designers first considered a flying wing, then undertook the radar tests that persuaded them that a flying wing worked both for aerodynamics and avoiding radar. Second, Tacit Blue had immersed Northrop’s designers in the use of curves to defeat radar. Curves not only helped the plane fly better; they also improved its stealthiness across a broader range of radar frequencies. Third, the B-2 had to have a radar in it for navigation and targeting, and Northrop had learned from Tacit Blue how to incorporate a radar in a Stealth plane … Losing the F-117, in other words, was crucial to winning the B-2. The consolation prize for the first round, Tacit Blue, held the key to the last round.

> It was Lockheed that had proposed a flying wing for Tacit Blue, and Air Force program managers then nudged Northrop in that direction. The flying-wing idea for the B-2 first came from outside Northrop—indeed, from its main competitor.

> Most airplanes are built from the inside out, starting with the internal framework as a sort of skeleton and then putting the skin on at the end. Building from inside out, however, means that errors in tolerance multiply. In order to maintain the rigid specifications for the B-2’s skin, Northrop built it from the outside in,

> The Pentagon’s fact sheet released in mid-1986 had revealed that the B-2 cost $277 million per plane. That price tag worried Pentagon managers, who thought in terms of cost-to-kill ratios, and who wondered what Soviet targets were worth risking a $300 million plane. … the Air Force announced that the B-2’s cost had risen to $44 billion in 1981 dollars; including inflation, that made it $70 billion for 132 bombers, or $530 million per plane … Spreading the final development cost of $45 billion over only 21 planes sent the price per plane skyrocketing, and the B-2 became known as “the $2 billion airplane.” The demise of the Soviet Union meanwhile made the B-2 an airplane looking for a mission. The Air Force proposed using it for conventional strikes on rogue nations in the developing world, such as Libya, but at $2 billion per plane such missions were harder to justify. … (The F-117, by comparison, cost about $110 million per plane, including the prototypes.) … during deployment at Whiteman Air Force Base, that figure soared to 124 maintenance hours per hour of flight in 1996. As a result, only one-fourth of the deployed B-2s were actually mission-capable on average

> Fifty years earlier, during World War II, the American 8th Air Force lost one out of every twenty planes it sent into the skies over Germany, and only a third of the survivors dropped bombs within 1,000 feet of targets. In Iraq, Stealth aircraft were delivering bombs down airshafts, and not one was shot down. A single F-117 with two smart bombs was as effective as 108 B-17 bombers in World War II carrying 648 bombs … Even in the Gulf War itself, it took a wave of eight nonstealthy attack aircraft, escorted by thirty fighters and ECM (electronic countermeasure) aircraft, to attack one target—a ratio of almost forty airplanes per target. Meanwhile, twenty-one F-117s without escorts struck thirty-seven targets.

> Although Lockheed had the first and most public association with Stealth, Northrop may have benefited even more. Stealth had changed Northrop. Before the B-2 it was one of the smaller aerospace firms, occupying specialized niches. It hadn’t built a big bomber since Jack Northrop’s YB-49 half a century earlier, and the fighters it built were small, cheap, and designed for foreign markets. The B-2 brought Northrop into the big leagues,

> As Ben Rich put it in 1991, “The three-dimensional calculations you need to design stealthy curves, the kind you see on Northrop’s B-2…, were beyond us at the time.” This argument assumes that Northrop had such computers and that it relied on them. It hadn’t and didn’t. … Tacit Blue, which has been largely lost to history and seemed a dead end. In fact, Tacit Blue provided the stepping-stone from the faceted F-117 to the B-2 flying wing. … Northrop’s original Stealth proposal, like Lockheed’s, was a blended wing-body design. Then for Tacit Blue Northrop went the other direction, away from the flying wing, to a standard wing-body-tail. It was Lockheed that proposed a flying wing for Tacit Blue, and Air Force program managers then nudged Northrop in that direction. The flying-wing idea for Stealth aircraft first came from Northrop’s main competitor.

> Southern California was already home to much of the nation’s aerospace industry, but several major builders of military fighters or bombers—Boeing, Fairchild, Grumman, General Dynamics, McDonnell Douglas—were located outside Southern California, and none of them came up with Stealth. Stealth provides another example of what can happen in a creative, boundary-pushing culture, and perhaps only happen there.

> Although one may point to a few spin-offs from Stealth—say, the graphite-composite wings on Boeing’s new airliners—it otherwise had few civilian applications. The $50 billion or so spent on Stealth aircraft, in this view, would have been far better invested in, say, electronics or molecular biology, not to mention social programs such as education or health care. A more cynical view sees Stealth, and especially the B-2, as just a billion-dollar boondoggle, a pork-barrel project pushed through in secret, serving no pressing military need but generating giant profits for the companies involved. Stealth, however, did offer one revolutionary implication: as an alternative to nuclear weapons and a way out of the looking-glass labyrinth of nuclear strategy. Both Soviet and American strategists viewed Stealth, together with precision-guided munitions, as a way to deliver conventional weapons with sufficient accuracy and confidence to make a conventional attack as effective as nuclear weapons. … This reconsideration of strategic fundamentals failed to gain traction. Instead of weaning American strategy from its reliance on nuclear weapons, the US embraced the new conventional technologies, including Stealth, as a complement to, not a replacement of, nuclear weapons. The B-2 itself, a Stealth nuclear bomber, demonstrated the inertia of nuclear strategy ( )