_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.