Chapter 23: ►

_Secrets in the Cafeteria_

Building number 20, a relic of World War II, stood across the street from the main North American engineering offices, almost lost in a towering cluster of manufacturing buildings adjoining the Los Angeles International Airport. Building 20 housed the cafeteria for North American employees. During the first half of 1956 a cramped space alongside the cafeteria, which we called the “garret,” served as home for the X-15. The space was restricted. A North American guard stood watch at the doorway, which bore the sign: SECRET. UNAUTHORIZED PERSONNEL PROHIBITED. Visitors cleared to enter our workroom had first to sign a log book and be vouched for by an escort known to the guard on duty. It was all very hush-hush.

Under ordinary circumstances, North American builds airplanes like Detroit builds automobiles--on a razzle-dazzle production-line basis. The plant people are divided into teams which specialize--excel, I should say--in various fields of aeronautical engineering, design, and manufacturing. One group, the Advanced Design Section, conceives the new airplanes, inventing and laying out drawings of concepts. This group then takes these plans and, working closely with the Washington office of North American, submits proposals to the government or, in the rare instance of a commercial airplane, to airline executives. If the government buys a North American design, or awards a production contract, the remaining teams of the plant, amounting to some 16,000 people, move in to transform the layout drawings and specifications of the Advanced Design Section to working hardware.

This is an immensely complicated task, much too involved to describe in detail here. In brief, North American project engineers, working hand-in-glove with demanding “customer” project engineers, rough out a working concept of the airplane after first settling on the engine, or engines, usually furnished separately by the customer. In the initial stages the toughest problems are the weight and balance analyses, crucial to the final performance of the airplane. This delicate work goes on for months, turning hair gray and keeping many engineers preoccupied with wind-tunnel models of varying shapes and designs. The goal is to squeeze maximum performance out of the total package, taking into account infinite variables such as engine power and fuel consumption. Few people realize it, but in these days the fuel of an airplane, which, of course, constantly diminishes during flight and can change the center of gravity of the ship, sometimes accounts for sixty per cent of the total weight of the airplane at take-off.

When the general scheme is finally agreed upon, and the equipment to go into the airplane, such as armament, navigational and safety devices, has been fixed, North American project engineers then call upon all sections of the plant for help. Hundreds of engineers in the structures, aerodynamic, thermodynamic, manufacturing, and sub-systems design departments, go to work, designing specific pieces for the airplane--instrument panels, for example, and landing-gear shock absorbers, dive brakes, windshields, and fuel tankage. At the same time, still another team builds a full-scale “mock-up” or dummy model of the airplane, complete with instrument panel and moveable controls, which the design engineers use to insure that all of the tens of thousands of pieces of the puzzle fit properly before they order production.

The entire process from that point on is an endless, nerve-shattering battle to design parts that will perform the required task for the least weight. Every pound of payload (that is, armament, fuel, passengers) in an airplane can add more than seven pounds of weight to the total structure which the engine, with a fixed thrust, must force through the air. The drive to save weight is restrained only by safety considerations. Even these are pared to the bone. The safety factor of a big, lumbering merchant ship is about ten to one; that of a modern jet airplane, about one and a half to one, at best. The reason is simple. On a ship an engineer can design a motor to run, say, an electric fan, with little concern for total weight. Thus he builds it big and tough. It works fine, but it weighs twenty pounds. On an airplane engineers design a fan to perform the same job, but stay within a weight limit of, say, one pound. The result is a thin, sophisticated product--usually new and untried--with a minimum margin of safety.

The North American Project Engineer rides herd on the entire plant force assigned to his airplane, watching schedules and doling out weight restrictions to engineers like so many gold doubloons. Each piece that goes into the airplane is tested for strength and reliability a hundred times over, under the amazing variety of temperature ranges which the modern airplane encounters in flight. A sample is fitted in the mock-up. When all the parts are in place, the customer conducts a formal inspection of the dummy plane, probing for weaknesses, suggesting improvements, and usually adding items, again driving the engineers into weight-trimming frenzies. Many additional customer checks follow the mock-up inspection as the work progresses.

When, at last, the customer is satisfied, or as nearly satisfied as possible, he gives a green light and the North American Project Chief “freezes” the design. At that point detailed engineering drawings are released to the Manufacturing Division or to various subcontractors--“vendors,” as we call them in the trade. Manufacturing brings all of the tens of thousands of parts together at the right time and place on the assembly line, and soon thereafter the near-miracle is done. Finished airplanes roll out the door for a final painting or polishing in the California sunshine. Following several shake-down flight tests by North American pilots, the new planes are then delivered either to Edwards for customer tests, or, if the airplane is a proven concept, to operational units specified by the customer.

The experimental X-15 did not fit this general production scheme. It began like other North American projects in the Advanced Design Section. But because it was something special and only three models would be built, North American conceived an unusual method to see the X-15 to completion. Management formed a special team under direction of Advanced Design, but divorced from the other departments of the plant, each man a specialist in one phase of aircraft design or manufacturing. To boss this group, management selected Charles Feltz, a 39-year-old mechanical engineer, who was pulled off the F-86 project. Lacking other quarters for this new team, management temporarily assigned it to the cafeteria building.

Charlie Feltz was truly astonished by the assignment. Until he was named to head it, he had never heard of the X-15 project. It may seem surprising, but in a huge, decentralized company such as North American, project engineers are busy with their own problems and rarely have time to rub elbows with advanced design engineers, and vice versa. Moreover, from its inception the X-15 was a closely guarded secret. Thus Feltz was stunned by it all when I joined the X-15 group--consisting of eleven North American engineers besides Feltz--in the garret adjoining the cafeteria.

* * * * *

“Morning, Charlie,” I said, sticking out my hand.

Feltz was sitting at a cluttered desk pushed into one corner of the X-15 home. He was a short man with rumpled, graying hair and deep green eyes. He was a native of Texas, a graduate of Texas Tech and, as I soon learned, he affected a country-boy air. He dressed informally and butchered the King’s English. Behind Charlie’s relaxed exterior, however, lay a steel-trap mind and an unyielding ambition to build good airplanes. He had joined North American in 1940, on the eve of the industry’s gigantic expansion. He had not only survived the production ordeal of World War II but had also risen to the top of the best company in one of the most competitive professions in the world. In many ways Charlie Feltz reminded me of Chuck Yeager. In appearance and ability he was to the design of an airplane what Yeager was to the flight of an airplane.

“’lo, Scotty,” Feltz said, eying me casually. “Welcome aboard. Maybe you can give us some idea what this darned thing is all about.” He raised up a sheaf of about twenty drawings which had been passed on to him from the Advanced Design Section. Appropriately enough, I noted, these drawings had been prepared by two engineers named Owl and Canary. Having won the competition, these engineers had moved on to other projects and were no longer concerned directly with the X-15.

It is true that in the beginning North American management, completely absorbed with profit-making production-line airplanes such as the F-86, F-100, and other series, paid the X-15 scant attention. At first the X-15 was an annoyance to be tolerated. To be perfectly frank, only a few of us on the small X-15 team really grasped the fierceness of the tiger we had by the tail. Feltz, however, happened to be one who knew. It was characteristic of him to play ignorant about it. As I learned, that was his way of finding out even more, or of sizing up new men assigned to him.

If the X-15 ill-fitted North American’s usual method of producing an airplane, I certainly ill-fitted the X-15 team concept. I was something of a mystery at first, a kind of fifth wheel. I did not work directly for Feltz. I was hired by someone else and my paycheck came from another source. For all Feltz knew, I might have been some vice president’s son-in-law. The arrangement for both of us, accustomed to a more or less rigid bureaucratic structure, was awkward and uncomfortable. In contrast, say, to those of a structural engineer or an aerodynamic heating engineer, my duties were undefined. Lacking a specific slot on the team, Feltz entered me on the rolls as a “Design Specialist,” which seemed broad enough to cover my general role as a high-level adviser or consultant to the project.

On that first day, after Feltz had introduced me to the small X-15 team, we returned to his desk and talked a long time about the ship. Although the precise limits or mission of the airplane had not yet been established, the general outlines were known and the design had more or less been set by NACA engineers together with Hugh Elkin’s Advanced Design group. There was enough on paper to indicate that Feltz faced the most challenging assignment of all aeronautical engineers in the fifty years of aviation history. After our talk I went back to my desk, lost in wondrous thought.

* * * * *

What was this big tiger we had by the tail? I studied the sheaf of drawings Charlie Feltz had turned over to me. I was familiar, of course, with the various bits and pieces, but this was my first opportunity to think of the project in terms of hardware. It was enough to excite any pilot or engineer.

In her three-dimensional profile, as conceived then, the X-15 shape appeared fairly conventional. In the side view she looked something like a high-performance jet fighter, poised in a level position, resting on nose wheel and center skids. (The X-2 skid concept had been carried on to the X-15 primarily as a weight-saving measure.) She had a tall, sweeping, vertical tail, elongated nose, and a smoothly fared-in, V-shaped cockpit canopy. Her wings were stubby and straight, like those on the X-3; they were mounted far aft on the exceptionally long, trim fuselage, almost butting against the horizontal stabilizer.

According to the drawings and concept in those early days, the X-15 would be carried aloft in the belly of a B-36 mother plane. The B-36 was an enormous ten-engine bomber, built by the Air Force in quantity to deliver the nation’s largest nuclear bombs. In time, on this peaceful mission, the B-36 would depart Edwards with its fifteen-ton load and head to the launch point near Salt Lake, Utah, four hundred miles to the north. The mother plane would drop the X-15 at a launch speed of Mach .7 and at an altitude of about 35,000 feet, fast enough to insure stability at launch and high enough to avoid the fuel-wasting contact with the “thick” atmosphere. On its own then, the X-15 would fly south toward Edwards over the route we at NACA had conceived several years before. The rocket engine would burn for 88 furious seconds, consuming eight tons of fuel. After burn-out the X-15 would coast silently on course for Edwards and land dead-stick but hot on Rogers Dry Lake in the desert.

The one fact that made the X-15 far from conventional was the power-plant. It was not shown in detail on the drawings, but the entry on the specification sheet told all: “ENGINE. REACTION MOTORS, INC. XLR-99. THRUST 57,000 POUNDS AT 40,000 FEET ALTITUDE.” Like the engine in the X-2, this engine was to be throttleable; it had nine times the power of the Reaction Motors engine in the X-1 or Skyrocket. It would generate nearly one million horsepower, or as much power as seven Navy cruisers. On a shallow, ballistic-flight profile, it would hurtle the X-15 to a maximum speed of 7200 feet per second, which is over a mile and a quarter a second, 75 miles a minute, and better than 4500 miles an hour, or about Mach 7.0, twice as _fast_ as man had ever flown. On a “zoom,” or steep ballistic-flight profile, the powerful engine could boost the X-15 to an altitude above 250,000 feet, twice as _high_ as man had ever flown. In between those extremes, the X-15 could explore more unknown areas than all of the research airplanes in history, and then some.

To meet these dramatic dimensions of flight and to perform her role as a research tool, the X-15 had some new and startling wrinkles which were detailed in the specifications. For example, in addition to the conventional control system for flight in the relatively thick air girdling the earth, the X-15 was to be equipped with a set of “ballistic” controls to steer the ship in the virtually airless space above 200,000 feet. These were small rocket motors on the nose and wingtip through which the pilot could squirt a jet of hydrogen-peroxide steam to tilt the wing or raise or lower the nose. This system had never been tried. But NACA was already busy with an experimental set of ballistic controls it had installed in the Bell X-1-B rocket plane. Jack McKay later tested the system at an altitude of 70,000 feet.

When the X-15 plunged from its extreme altitude back into the thick coating of earth-atmosphere, it would be subjected to intense frictional heat like a meteorite, or the nose cone of a ballistic missile. To withstand this tremendous heat, estimated to be dozens of times greater than any airplane had ever before experienced, the fuselage nose and wing leading edges were to be built of an ablating material which would absorb the brunt of the heat and then erode and melt away, leaving the major portion of the fuselage and wing-structure intact. The remaining skin of the airplane was to be made of a new metal known as Inconel X, a nickel alloy capable of withstanding heat up to 1200 degrees Fahrenheit without losing its structural integrity. This metal would also serve as a conductor to soak up heat throughout the plane. One of the principal purposes of the X-15 was to see what effect extreme temperatures would have on the airplane structure and equipment, not to say the pilot.

Such, then, in briefest outline, was the grand and simple concept. It was truly revolutionary to me. For fifty years we had struggled to learn to fly within the earth’s atmosphere. It had been fifty years of sheer technical agony. Now we had designed an airplane that would not only fly double the speed man had ever flown in this coating, but also zoom beyond it--to the fringes of space. The ship would soar a few moments in this dark weightless void. Then it would make a _controlled_ descent into the atmosphere and finally land on an airfield like an ordinary airplane. It occurred to me that the X-15 was more than simply an airplane or research tool. It was the prototype of man’s first space ship. In time, it was clear, all useful, piloted space craft would follow in the trail blazed by the X-15.

How could I best help Feltz in this fabulous project? Sitting silently at my desk I thought about it for many hours. I could see the mock-up inspections that lay ahead, the inevitable delays, breakdowns, and requests from the customer for added equipment. The X-15, if permitted, could become the perfect pigeon for every new invention, half-baked or otherwise, of every engineer in the country. Each new device would add more and more weight to the total and, since the engine thrust was fixed, cut the performance. It would also add to the complexity and inevitably delay the day I first flew her. This past pattern of research airplane growth simply could not be allowed to happen with the X-15 and cause her demise like a few of her predecessors. Someone had to resist it, if possible, before it began. Most of these additions, I knew, were likely to occur in the cockpit, or “pilot’s office,” my special province, the command post of the X-15. With my background in rocket planes and as the X-15’s designated pilot, I concluded, I was probably least vulnerable politically and thus best equipped to say “no.”

Thus, that day, my specific role in the X-15 project was defined to my satisfaction. I would be the X-15’s chief son-of-a-bitch. Anyone who wanted Charlie Feltz or North American to capriciously change anything or add anything in the cockpit, or in the whole X-15, for that matter, would first have to fight Crossfield and hence, I hoped, would at least think twice before proposing grand inventions. This negative approach was not a role I particularly treasured. It was quite foreign to my nature, which is basically positive, I think. But I was willing to play any role that would best serve our ends and contribute to the prestige of the nation by seeing the X-15 completed and flying on schedule.