“_Please Come to a Complete Stop_”
Over the swiftly passing years the face of the Edwards base had
dramatically changed. The Air Force, NACA, and civilian contractors
had erected modern, air-conditioned offices, engineering spaces, and
massive hangars. A new concrete runway, miles long and as much as
two feet thick, crossed the flatlands. Installations for fueling and
testing experimental airplanes and rocket engines were now formal,
restricted areas. Pancho’s Happy Bottom Riding Club was gone, gobbled
up by the Air Force, which pushed the boundaries of the base in all
directions, including up. The sleek, modern Edwards tower occupied
the space that once held the complete, historic town of Muroc. The
old tarpaper “Kerosene Flats” living area had been replaced by
comfortable housing. Edwards was big and busy, encumbered with red
tape and a new formality.
The people had changed, too. General Al Boyd’s one-man show, the
jet-age flying circus, had passed into history. The new Edwards
commander was a no-nonsense general, Stanley Holtoner. Holtoner
endeared himself to no one by deliberately snubbing Pancho Barnes,
but he reorganized the expanding base on a businesslike basis. The
Air Force pilots who had reigned in my early days at Edwards--Ridley,
Wolfe, Sellers, Bryce, Hoover, Lathrop, Gregorious, Popson--were
gone, almost all to their graves. Yeager had moved on to other
assignments. Only Pete Everest hung on, playing a tight-fisted
waiting game with the lagging X-2.
The shift to the elaborate new NACA “laboratory” had considerably
changed the atmosphere in our outfit. More distant now from the
mechanics, and the smell of grease and fuel, we discarded our sport
shirts for business suits and ties, and played the scientist role
to the hilt. This was inevitable. NACA’s record at Edwards had far
exceeded all expectations. Our prolonged tour on the frontier of
flight had not only developed millions of data points, but new theory
as well. We had challenged many old and accepted wind-tunnel methods.
We had raised warning flags on trouble to come and desperately tried
to head it off. In truth, the High Speed Flight Station was no longer
a gypsy caravan camped on the fringes of Edwards, but a solid,
permanent NACA installation, an important new source of aeronautical
think-how and know-how. Occasionally I longed for the old racing-pit
days, the time of sweating all night long side-by-side with a bunch
of mechanics over a balky valve, but I knew this deprivation was the
price of progress.
The emphasis in the air had changed as well. The rocket airplanes
were still far and away the most spectacular craft on the base.
But the big push was now placed on the new production airplanes,
which were afflicted with the aches and pains of faster and faster
speed. These airplanes had to be made safe--or as safe as humanly
possible--for the green Air Force second lieutenant just out of
flight school.
The aches and pains had been anticipated years earlier. Flying
near the speed of sound, an airplane creates a resisting field
in its path. The air immediately ahead of the plane, in effect,
is transformed into a rugged area of angry sound waves which
criss-cross, backwash, tumble, speed up, and slow down, behaving
somewhat like the foaming water in an ocean wave when it tumbles
against a rock-bound coast. In the beginning at Edwards the job
was to design and fly a plane to the edge of this coast. The
bullet-shaped X-1, deliberately built to withstand tremendous
stress, had blazed right through to the smooth beach beyond. But
military airplanes, which could not be so heavy and brutal, had a
tough time of it. As they felt their way along, they were battered
and smashed about in the surf. And when they finally reached the
beach, they still had trouble.
The most common afflictions the airplane experienced in piercing the
turbulent trans-sonic air were two abrupt, divergent motions which
we called pitch and yaw. These were terms adopted, appropriately
enough, from the seamen. Pitch describes the movement of the airplane
if the nose suddenly and unexpectedly jerks up or down, like the
bow of a ship in a heavy sea. Yaw describes the movement of the
airplane if the nose cocks sharply to left or right, somewhat like
the clumsy wallow of a vessel in a following sea. When or if both
abrupt movements occur simultaneously--a dreadful and often fatal
sequence--it is called “coupling.”
The impact of pitch and yaw on the airplane varies with altitude
and speed. In the thick air of low altitudes a fast-moving airplane
pitching or yawing severely is subjected to intense strain, so much
that it is not uncommon for the ship to disintegrate in mid-air.
At higher altitudes where the air is much thinner, a fast-flying
airplane can “take” a greater divergent motion. If it yaws, pitches,
or couples, the airplane simply skids through the air in whatever
awkward or ungainly position it assumes. However, an airplane in
such altitudes must be slowed before it reaches the thicker air;
otherwise, it will enter this blanket beyond stress-design and
disintegrate. At any altitude, if a plane flips out of control, the
pilot must respond with care and skill. Over-controlling, or pumping
on the wrong controls, compounds the problem.
There was no known way to avoid completely such divergent motions in
supersonic airplanes built especially for combat and near-routine
take-off and landing on ordinary airfields. Thus, from the beginning
we had focused attention on “damping” the motions, striving for
minimum instability by various wing and tail designs, angles of
sweep, and mechanical devices on the wing called fences and slats.
Control systems were devised with a built-in “damping” system which,
in theory, automatically sensed a divergence and automatically moved
the controls just enough to compensate. These were called SAS, short
for Stability Augmentation System.
After production airplanes were delivered to Edwards, the
experimentation continued unabated. New vertical tails and fancy
devices were tacked on the airplanes. The horizontal stabilizers were
moved to new positions on the fuselage.
During 1954, like other pilots at Edwards, I was swept up in the new
race to bring the fast new jets within safe flying limits. I made
twenty-five additional flights in the Skyrocket in support of these
experiments. In between, I went aloft many times in early-model
production aircraft such as the F-84-F, an advanced version of the
Republic Thunderjet; the F-102, a direct outgrowth of the horrible
delta-wing XF-92-A; and the “hard-wing” F-86--so-called because its
automatic slats were removed--which had been hastily engineered
especially to destroy MIGs in Korea. The F-86 Sabrejet particularly
held my interest from an aeronautical-engineering point of view.
The plane had already earned its niche in history, and hundreds
were flying from Air Force bases, but its complete range of dangers
had yet to be defined in any report. The thought that some second
lieutenant might be killed because we at Edwards had fallen down on
the job haunted me. I resolved to do something about that particular
airplane.
Customarily we began investigations which would push an airplane to
the limit at high altitudes, where the air was thin and the ship
would stay in one piece if it uncorked. Joe Walker, Stan Butchart,
Jack McKay, a promising new pilot at NACA, and I divided the
hard-wing F-86 work, starting at 40,000 feet and working down slowly.
As we edged down into the thick air at lower altitudes, the F-86
pitch-up became more violent and dangerous. Our boss, Joe Vensel,
drew the line. He ruled that we could not deliberately uncork the
airplane below 30,000 feet.
* * * * *
“But the most important area,” I said to Walt Williams, protesting,
“is down around 25,000 feet. That’s where the military pilot can get
in serious trouble, chasing a target sleeve or something. If this
plane has a serious divergence at that altitude they ought to know
about it.”
“Look, Scotty,” Walt said, “we’re in the middle. We can’t come up with
a negative opinion of some company’s airplane like that. All we can
do is fly the thing and collect data and present the data objectively
in an NACA report.”
“Okay, fine,” I said. “Then let’s keep on going. Let’s do the
30,000-foot data and then drop down to 25,000 feet.”
“That’s up to Vensel,” Williams said. “He’s your boss.”
“Vensel says no.”
“Then the answer,” Williams said, “is no.”
For the first time in my life I deliberately violated my boss’s
orders. Without rechecking with Vensel, I recorded the hard-wing
F-86 maneuvers at 25,000 feet. As we all expected, the pitch-up was
severe. The airplane held together--North American traditionally
built rugged planes--but the stress, or G force, caused me to black
out. A pilot bent on a mission other than paying strict attention to
the unique maneuver could get in serious trouble. When I turned over
the data, Vensel was understandably incensed. After the data were
released--to save the lives, I hope, of some pilots--Vensel pouted
and claimed I had conducted the test at 25,000 feet to prove that the
other pilots were “chicken.” Walt Williams called me to his plush new
office, decorated with new space-charts, and gave me unshirted hell.
I guess I tossed it back as fast as he dished it out.
* * * * *
Another of these advanced planes with supersonic aches was the North
American F-100. It had been flying experimentally, off and on, about
one year, when we received the twenty-third production model at NACA
in September, 1954. She was a powerful, wonderful beast, capable of
reaching Mach 1.3 in level flight. At that stage in her test-flight
program, mechanics spent fifteen hours working on her for every one
hour she spent in the air. She had a reputation for being mean,
if mishandled. She had uncorked and disintegrated, killing North
American’s top test pilot, George Welch. There was a big debate
raging among the pilots at Edwards about whether or not the F-100
could be landed dead-stick. North American had not yet demonstrated
it. It fell to me to find out on my first F-100 flight.
We were down for an 0800 take-off, but the unbeatable NACA mechanics
were ready ten minutes before, so I went aloft ahead of schedule,
before the radars and tracking stations were warmed up to zero in
on me. There had already been built at North American new, bigger
vertical tails for the F-100. We needed some specific data points.
Our F-100 was packed full of NACA instruments. The ship was not a
research airplane. I had declined a chase plane.
Poised on the end of the new three-mile concrete runway, I
fire-walled the throttle. The F-100 rolled, picked up speed, and then
stood on her tail, afterburner blazing, climbing almost vertically
into the desert sky. I was quite impressed. The F-100 was no toy but
it handled well. By then, North American had built thousands of F-86
jets in all models and it was obvious they knew what they were doing.
When I reached 35,000 feet, I leveled the ship. At that very instant
a blaze of red flashed on my instrument panel. Fire in the compressor
section! My old first-flight luck was stalking me again. (It had
never left me, really. Some time before this, during a first flight
in a new F-84-F, I had run into serious trouble and made an emergency
landing on the lake.)
There were two fire-warning lights in the F-100. One covered the aft
end of the engine, the other covered the forward end, or compressor
section. A fire, or heating up, in the aft end was not uncommon in a
jet with afterburner. If the pilot throttled back or otherwise varied
the running conditions of the engine, it usually disappeared and the
light went off. But a fire warning in the compressor section, crowded
with fuel lines, gear boxes, and other vital parts, was serious
indeed. Usually a compressor section fire did not last long; it raced
through the intake into the compressor and the plane disappeared in a
puff of smoke and flame. There was an old and tired axiom about it at
Edwards: “If you see a compressor fire-warning light and you haven’t
blown up, well, you’re going to in just a second.”
A small notice riveted to the panel next to the compressor
fire-warning light informed me:
COMPRESSOR SECTION FIRE WARNING LIGHT ON:
STOP-COCK ENGINE. IF LIGHT REMAINS ON BAIL OUT.
A hell of a sign to put in a cockpit, I thought. It inhibits one’s
thinking.
I got busy fast. I throttled back on the engine. As I did, the
fire-warning light flickered and dimmed. Then it flashed back on
again full-strength. Following the instructions on the panel, I
stop-cocked the engine completely, turning off all fuel valves.
The engine unwound and settled down to a slow wind-milling. The
fire-warning light flickered but remained on.
When the powerless F-100 slowed to glide speed, the leading edge
slats, which provide lift and stability in slow flight, cracked and
extended automatically. This produced a steady rumbling noise which
I assumed to be the fire blazing in the engine air-intake directly
beneath my feet. (At that time few pilots had remained in an F-100
with a wind-milling engine long enough to hear that slat noise.)
I called NACA radar and asked them to take a look through their
field-glasses and see if I was trailing smoke. Since I hadn’t blown
up yet there was a possibility that the fire might blow itself out.
As a matter of professional pride, I was reluctant to abandon a new
airplane that was still in one piece. Somehow, NACA radar failed to
find me. After several garbled radio exchanges with them, I snapped
impatiently: “Never mind.”
The fire-warning light blazed steadily. However, I saw no other signs
of real fire, so I concluded that it was a false warning. I would
bring the ship down dead-stick. To my knowledge at that time, only
one man, North American test pilot Bob Hoover, had ever dead-sticked
an F-100. On that one occasion the struts had been pushed up through
the wing, demolishing the plane. As a matter of fact, North American
test pilots were then flipping coins to see who would deliberately
bring an F-100 in dead-stick to fulfill a requirement of the Air
Force acceptance tests. I was not concerned. Dead-stick landings in
low L over D airplanes were my specialty. Every test pilot develops a
strong point. I was certain that my talent lay in dead-stick landings.
With the engine then idling and generating no energy to the plane’s
systems, I was running out of hydraulic pressure to operate the
controls. Following the handbook instructions, I pulled a lever which
extended a miniature “windmill” into the slipstream. This “windmill”
churned, building up pressure in the hydraulic lines. Unknown to me,
there was a major leak in the line. The windmill was not helping, but
hurting me. It was pumping hydraulic fluid overboard as fast as it
could turn.
I called Edwards tower and declared an emergency. All airborne
planes in the vicinity of the base were warned away from the lake
area. I held the ailing F-100 on course, dropping swiftly, lining up
for a dead-stick lake landing, following the same glide-path that
I used for the dead-stick Skyrocket. I flared out and touched down
smoothly. It was one of the best landings I have ever made, in fact.
Seconds later, while the F-100 was rolling out, the remaining bit of
hydraulic pressure in the control lines drained out and the controls
froze.
I then proceeded to violate a cardinal rule of aviation: never try
tricks with a compromised airplane. The F-100 was still rolling at
a fast clip, coming up fast on the NACA ramp, when I made my poor
decision. I had already achieved the exceptional, now I would end it
with a flourish, a spectacular wind-up. I would snake the stricken
F-100 right up the ramp and bring it to a stop immediately in front
of the NACA hangar. This trick, which I had performed so often in the
Skyrocket, was a fine touch. After the first successful dead-stick
landing in an F-100, it would be fitting.
According to the F-100 handbook, the hydraulic brake system--a
separate hydraulic system from the controls--was good for three
“cycles,” engine out. This means three pumps on the brake, and that
proved exactly right. The F-100 was moving at about fifteen miles an
hour when I turned up the ramp. I hit the brakes once, twice, three
times. The plane slowed, but not quite enough. It was still inching
ahead ponderously, like a diesel locomotive. I hit the brakes a
fourth time--and my foot went clear to the floorboards. The hydraulic
fluid was exhausted. The F-100 rolled on, straight between the
yawning hangar doors!
The good Lord was watching over me--partially anyhow. The NACA hangar
was then crowded with expensive research tools--the Skyrocket,
all the X-1 series, the X-3, X-4, and X-5. Yet somehow, my plane,
refusing to halt, squeezed by them all and bored steadily on toward
the side wall of the hangar.
The nose of the F-100 crunched through the corrugated aluminum,
punching out an eight-inch steel I-beam. I was lucky. Had the nose
bopped three feet to the left or right, the results could have been
catastrophic. Hitting to the right, I would have set off the hangar
fire-deluge system, flooding the hangar with 50,000 barrels of water
and ruining all the expensive airplanes. Hitting to the left, I would
have dislodged a 25-ton hangar-door counterweight, bringing it down
on the F-100 cockpit, and doubtless ruining Crossfield.
Chuck Yeager never let me forget that incident. He drew many laughs
at congregations of pilots by opening his talk: “Well, the sonic wall
was mine. The hangar wall was Crossfield’s.” That’s the way it was
at Edwards. Hero one minute, bum the next. The fact that I was the
first pilot to land an F-100 dead-stick successfully, and memorized
elaborate and complete instrument data on the engine failure besides,
was soon forgotten.
The F-100 is a tough bird. Within a month NACA’s plane was flying
again, with Crossfield back at the helm. In the next few weeks I
flew forty-five grueling flights in the airplane, pushing it to the
limits, precisely defining the roll coupling. (On one flight the
coupling was so severe that it cracked a vertebra in my neck.) These
data confirmed, in actual flight, the need for a new F-100 tail,
which North American was planning to install on later models of the
airplane.
Every night after landing, I taxied the F-100 slowly to the NACA
ramp. At the bottom, placed there on orders of Walt Williams, there
was a large new sign, symbolic of the new atmosphere at Edwards. It
said:
PLEASE COME TO A COMPLETE STOP
BEFORE TAXIING UP RAMP