_Time for Extraordinary Action_
By January of 1958 the X-15 team had moved into high gear. North
American’s F-100 contract was running out. The production space was
absorbed by the jigs and dies for our three “space craft.” We had
subcontracted about two hundred items on the airplane to vendors, but
most of the ship was manufactured right on the premises.
By then all the engineering drawings--some six thousand altogether,
and one of them fifty feet long--had been released. The never-ending
battle to get the most from a part for the least weight was
reaching a climax. Charlie Feltz had detailed every man on our team
to keep track of the weight, to make certain the total did not
climb above our final estimate of 31,000 pounds. Since there were
more than 10,000 parts on the X-15 weighing a pound or more, our
weight-watchers were firm and exacting.
Everything about the fabrication of the X-15 was new and challenging
and therefore, from a technological standpoint, exciting. Every day
at his command post on the second floor of the engineering building,
Charlie Feltz faced a hundred new problems, each one of them a minor
crisis. As I look back on those long days and nights, I wonder how
he kept his sanity. We hear much about pressure on Madison Avenue
and in the city rooms of newspapers at press time, but no one can
persuade me that it is any greater than that we experienced on the
X-15 project. Night after night I returned to my home late--punchy,
almost shell-shocked. Month by month I watched Feltz aging, long
before his time. But no matter how intense the work, or how baffling
and seemingly insoluble the crisis, he seldom lost his country-boy
composure. I believe this fact, more than any other, held the team
together amicably under the great strain and enabled us to achieve
our goal.
Most of the technical details of the fabrication of the X-15 are,
sad to say, too involved to relate here. Thus I fear this marvelous
technological story will never be told in full. But there is one
understandable detail which I would like to describe. This is our
pioneering metallurgy with the skin of the X-15, Inconel X. In the
sense that it was new and untried, it was fairly typical of most of
the fabulous shopwork on the X-15.
Inconel X, as I have said, is a tough nickel alloy, capable of
withstanding high temperatures without losing its structural
integrity. When we launched the X-15 project, Inconel X had been
proven in a laboratory. But no one had ever built a machine of it.
There were no handbooks to tell us how to work it. For example, only
a few people in the nation had ever tried to weld Inconel X. The skin
of the X-15 had to be welded because traditional rivets were not
strong and resilient enough to stand the temperature beating without
leaking. Besides, we figured we could save a thousand pounds of
weight by eliminating rivets.
Consider half of the X-15 wing as typical of the metallurgy problem
we licked. From fuselage to wingtip, the wing is only six feet long.
At its peak cross-section the wing is only eight inches thick. There
are seventeen spars in the wing. At the root near the fuselage joint
the spar caps are 3/16 of an inch thick. At the tip they are a mere
30/1000 thick.
When the X-15 re-entered the heavy atmosphere of the earth, we had
calculated, the leading edges would be subjected to 1200 degrees
Fahrenheit. They would glow red from the heat. A few inches aft
on the wing, however, the temperature would be much lower. Where
the temperature is higher, the metal must be thicker and heavier to
carry the load. But at the same time it is foolish to waste weight by
overloading at points where the temperature is low. Thus we viewed
the wing skin in hundreds of sections, each capable of withstanding
a certain maximum temperature, plus a safety margin, and each of
different thickness to save weight and still carry its share of load.
Inconel X came to us from the manufacturer, International Nickel,
in sheets 36 inches wide and 140 inches long, rolled and milled to
normal aircraft specifications. We figured that if the total skin of
the X-15 were as much as 1/1000 of an inch too thick, it would cost
us a critical 100 pounds in weight. Thus when we received the sheets,
we re-milled them in grinders down to incredibly low tolerances.
Since each different piece of the wing skin varied in design
thickness from the others, each had to be ground separately to those
tolerances. (The same was true of the fuselage and tail-skin.) It was
like making a Stradivarius, if not even more delicate.
Once these pieces were completed and the spars set in massive jigs,
the technicians then set about welding the many parts into one solid
piece. Ordinary welding is difficult enough: extreme care must be
taken to see that no “bubbles” form to weaken the joints. Welding
Inconel X almost drove our men to distraction. They worked like
artists, experimenting with new strokes and mixtures until they were
able to produce a true masterpiece of craftsmanship. Each of the
thousands of joints was X-rayed to make certain no bubbles had formed.
The pieces, after welding, were heat-treated like fine steel
knife-blades. Let me explain that further. When you weld two pieces
of metal together, each is subject to varying temperatures from the
welding torch. As the torch moves along, the new area heats up while
the one just passed cools. Thus there are stresses and strains in
the molecular structure of the metal undetectable to the naked eye.
By placing the entire structure in an oven after welding and raising
the temperature to 1900 degrees we were able to cool it uniformly,
ironing out the strains. After this stress-relieving process each
piece remained in the oven for twenty-four hours at high temperature
to heat-treat or “age” the metal. Then the joint and the parent metal
were stronger than originally. After a fine polishing, the hundreds
of welds were impossible to locate with the human eye. The wing
looked like one solid piece of smooth metal.
Our metallurgists didn’t learn this new craft overnight; it took
years. They started out experimentally by building three mock
fuselages of the X-15 to serve as ground-test beds for the rocket
engines. One of these was installed at Edwards, the other two at
the RMI engine factory in New Jersey. This experience brought our
welders to the artist level, but when it came to building the three
airplanes, Feltz was even more demanding. In fact, as I recall,
about seven different wing-skins were built for the first airplane
before he gave his approval. In the end, I think, the experience and
knowledge we gained on this new frontier alone were worth the entire
cost of the X-15 program. It was one big reason we believed our case
for the advanced X-15 was sound. All future space projects will
benefit directly or indirectly from our work with Inconel X.
* * * * *
The RMI XLR-99 rocket engine was steadily falling behind schedule.
This fact was no secret. It was well known in the Air Force, NASA,
and throughout the entire aircraft industry. There were many
technical locusts plaguing the RMI engineers. One of the biggest was
the fact that during tests, while burning the X-15’s exotic fuel
mixture of Lox and ammonia, the rocket-engine chamber had a habit of
exploding. By February, 1958, the XLR-99 engine was exactly one year
behind schedule and considerably heavier than originally planned.
I believe that under ordinary circumstances our customer would simply
have ordered us to wait for, or “sweat out” the engine. But the X-15
was not being put together under ordinary circumstances. She loomed
on the horizon as a national symbol of our ability, or lack of it,
to make good in space. Because of this and other factors, insofar as
the engine was concerned, it was time for extraordinary action. But
complex rocket engines don’t grow on trees. What to do?
Charlie Feltz called for help. Stormy, who was then also busy laying
out plans for the Air Force F-108 fighter and the B-70 bomber among
other things, took over the X-15 engine crisis at full throttle,
bringing his authority to bear. He got on the telephone to North
American’s Rocketdyne Division. Could they run some Lox-ammonia
tests on a Redstone chamber and see what happened? Rocketdyne
converted a Redstone chamber and successfully conducted the tests.
(Rocketdyne engineers even made the Redstone chamber throttleable.)
We were impressed, because these tests were run off in a matter of
weeks without interfering with Rocketdyne’s major ballistic-missile
projects, and at no cost to the government.
After the tests Stormy again asked the Air Force to allow us to
equip the X-15 with a working engine. Again the proposal was turned
down, for most of the aforementioned reasons. But the Rocketdyne
demonstrations had a dramatic impact at RMI. RMI engineers, beaten
at their own complex game by the great depth of North American
engineering talent, turned to the XLR-99 engine with new and vigorous
enthusiasm. But we knew that no matter how hard they worked they
couldn’t make up much of the lost time. What was the answer?
We debated that question during countless meetings with Stormy and
Charlie Feltz in the following weeks. Then one day our “dreamer,” Bob
Carmen, spoke up.
“I’ve been doing a little figuring here. Suppose that instead of
waiting for the XLR-99 engine we substitute, pending its arrival, two
X-1-type engines. They could be built in a few months, at most.”
I flew out of my chair.
“Boy,” I said, “if you really want to kill off a project, this is one
way to do it. Start yielding. Start making inferior substitutions.
Make the airplane more complex. Sure. That’s what happened to the
X-3, the X-1-A series and the X-2. If we allow that to happen to the
X-15, we’re going to wind up with nothing again.”
“Now, hold on a minute, Scotty,” Feltz said. “We’re really up a tree
here. We can’t use a Rocketdyne engine. We have to wait for the
XLR-99. Maybe Carmen has got a point here. Pending the arrival of
the big engine, we could be checking out the other systems in the
airplane.”
“Damn it, Charlie,” I snapped. “I think we’d be making a big mistake.”
“Let’s take a look at the performance we might get out of the two X-1
engines,” Feltz said, obviously warming to the idea.
“Can we use the same fuel-tank system?” an engineer asked.
“Yes,” Carmen said. “Nothing about the fuel tanks would have to be
changed. You just change the engine, substituting the eight small
chambers for the one large one. I think we could fix it so that when
it arrives the big engine could be installed with hardly any delay.”
“What’s the fuel for the X-1 engine?”
“Lox and alcohol. We just put the alcohol in the ammonia tanks. No
sweat.”
“There’s another advantage, too,” someone else put in. “Those
engines have a lot of time on them. They ought to be reliable. The
X-1 engines are not throttleable. But each engine has four barrels.
That’s a total of eight barrels, all of which can be lighted off
separately. Thus you can attain just about any speed range you want
within the limits of the airplane. I mean, it would be almost the
same as being throttleable.”
“I figure the extreme performance with these two engines at about
Mach 3.5 and 150,000 feet,” one engineer said. Each X-1 engine would
have a thrust of about 8,000 pounds or a total in both chambers of
about 16,000 pounds--compared to 57,000 pounds for the XLR-99. The
two X-1 engines together weighed more than the single XLR-99 engine.
“Mach 3.5 and 150,000 feet,” Feltz repeated. “That would give
us enough performance to make a good many demonstrations on the
airplane. In fact, we could make all the structural demonstrations,
as well as re-entry, ballistic controls, Lox top-off, and so forth.
Let’s see what the customer says.”
[Illustration: X-15 profile. NAA photo.]
[Illustration: The X-15 inboard profile. NAA photo.]
[Illustration: Owners, builders, and customers. From left: Harrison
Storms, Maj. Gen. Haugen, Ray Rice, Brig. Gen. Cooper, Walt Williams.
NAA photo.]
[Illustration: Blood, sweat, and tears: Feltz, Robinson, and Benner.
NAA photo.]
[Illustration: The X-15 flight mission. NAA photo.]
[Illustration: The paper weighed more than the airplane. NAA photo.]
[Illustration: Ground-testing the X-15 escape system. NAA photo.]
[Illustration: A rocket test sled of the X-15 escape system begins a
run at Edwards. The canopy ejects ... NAA photo.]
[Illustration: ... and blows away while the seat with dummy emerges.
NAA photo.]
[Illustration: Powered ejection ends ... NAA photo.]
[Illustration: ... and the chute begins to deploy automatically. NAA
photo.]
[Illustration: The dummy separates from the seat ... NAA photo.]
[Illustration: ... for a soft landing on the desert. NAA photo.]
[Illustration: Farmer’s son tries out early-model experimental Clark
pressure suit. NASA photo.]
[Illustration: Bill Bridgeman wearing an early-model Air Force
partial-pressure suit. Douglas photo.]
[Illustration: A rubber tire preserved for posterity. David Clark’s
statue of me. Photo by Marvin Richmond.]
[Illustration: The pressure-suit break-through: link-net material.
NAA photo.]
[Illustration: Fitting the helmet. NAA photo.]
[Illustration: Posing for publicity. NAA photo.]
[Illustration: The centrifuge gondola at Johnsville. NAA photo.]
[Illustration: Clip from the horror film. NAA photo.]
[Illustration: Clip from the horror film. NAA photo.]
[Illustration: Clip from the horror film. NAA photo.]
[Illustration: Building the mock-up. NAA photo.]
[Illustration: A demonstration in the simulator. Kincheloe presses in
for a close look; behind him is Joe Walker. NAA photo.]
[Illustration: The Inconel X wing skin was ground to watchmaker’s
tolerance. NAA photo.]
[Illustration: The hosts and guests for the roll-out party, October
15, 1958. From left: Mr. and Mrs. Dutch Kindelberger, Mrs. Nixon and
the Vice President, and Lee Atwood. NAA photo.]
[Illustration: Crossfield to Nixon: “My job is not nearly so risky as
yours, sir.” NAA photo.]
[Illustration: First trip: heading for Edwards by truck. NAA photo.]
[Illustration: The dawn of a new era: arriving at Edwards. NAA photo.]
[Illustration: Sam Richter briefs the flight-test team. NAA photo.]
[Illustration: Q. C. Harvey and I put in our nickel’s worth. NAA
photo.]
[Illustration: Rehash late the night before the flight. Clockwise:
the pilot; the B-52 launch-panel operator, Bill Berkowitz; Sam the
van man, and test director Q. C. Harvey. Cornell Capa-Magnum photo.]
[Illustration: Later with the crew. Photo by John Bryson.]
[Illustration: Still later: the countdown begins at midnight. Photo
by John Bryson.]
[Illustration: Later yet: flying tomorrow’s flight. Photo by John
Bryson.]
[Illustration: A few hours later, the carnival at dawn. Photo by John
Bryson.]
[Illustration: Moving the black bird into place ... NAA photo.]
[Illustration: ... and finally in place. NAA photo.]
[Illustration: Fueling up ... NAA photo.]
[Illustration: ... and loading peroxide ... NAA photo.]
[Illustration: ... and battening down the frozen hatches. NAA photo.]
[Illustration: Inside the van with Capt. Richardson, squatting. NAA
photo.]
[Illustration: Twenty minutes later, zipping up the outer layer.
Photo by John Bryson.]
[Illustration: Occasionally we wait a little. Photo by John Bryson.]
[Illustration: Bon voyage. Photo by John Bryson.]
[Illustration: Getting in the office. Photo by John Bryson.]
[Illustration: Pete Barker (right) with the pilot’s helmet. Photo by
John Bryson.]
[Illustration: Sometimes we wait again ... Photo by John Bryson.]
[Illustration: ... and recheck ... Photo by John Bryson.]
[Illustration: ... and things begin to work. Photo by John Bryson.]
[Illustration: The carnival moves out. Photo by John Bryson.]
[Illustration: Eyes on the stars. Photo by John Bryson.]
[Illustration: On the way to the stars. Photo by John Bryson.]
[Illustration: Straining for altitude again. NAA photo.]
[Illustration: The final countdown. NAA photo.]
[Illustration: Test directors on the ground look over my shoulder.
NAA photo.]
[Illustration: Stormy sweats it out in Sam’s van. NAA photo.]
[Illustration: Not far from the stars. Courtesy _National Geographic
Magazine_.]
[Illustration: Three ... Two ... One. Drop! NAA photo.]
[Illustration: Firing up. NAA photo.]
[Illustration: All eight going. NAA photo.]
[Illustration: “Burn-out ... jettison.” NAA photo.]
[Illustration: Gliding home. NAA photo.]
[Illustration: Picking up the chase. Photo by John Bryson.]
[Illustration: Gear down. NAA photo.]
[Illustration: Feeling for the lake. Photo by John Bryson.]
[Illustration: Touchdown. NAA photo.]
[Illustration: Roll-out. NAA photo.]
[Illustration: Stopping. Photo by John Bryson.]
[Illustration: Shutting down. NAA photo.]
[Illustration: Back to the drawing board. UPI photo.]
[Illustration: The price of progress: X-15 No. 3. NAA photo.]
[Illustration: Inevitably, a public accounting. Photo by John Bryson.]
[Illustration: Always another dawn. Photo by John Bryson.]
The substitution of the two smaller X-1-type engines was the obvious
solution to our dilemma. Actually, the customers had already
considered exactly the same idea. They approved it at once, and
Edwards got busy building up a dozen “proven” X-1 engines from old
parts. We planned to put two each in the first two X-15s, holding
the third X-15 in the factory for the first XLR-99 engine and other
improvements which flight test would generate. The remaining X-1
engines would be used for ground tests in the X-15 engine test beds
at Edwards and RMI.
A few nights after this decision was firmed up, Stormy, Feltz, and I
met after work in Charlie’s office at the North American plant. I was
still grumbling about “interim measures.” I let off steam.
“As far as I’m concerned, we’ve botched the whole deal,” I growled.
“You watch. We’re never going to get that big engine. The X-15 is
going to die on the vine. I’ve seen it happen before.”
“You’re wrong there, Scotty,” Feltz said. “We’ll get the big engine
sometime. Meanwhile, we’ll get a lot of Mach 3 data which will really
help the F-108 and the B-70. We’ll prove out the X-15 systems and by
the time the big engine comes the ship itself will be as reliable as
an F-100.”
We debated this point for a long while. Stormy was also in favor of
substituting the smaller engines. “I want to get this thing in the
air as fast as possible,” he said. “I think that as soon as we start
flying the X-15 and prove our systems and landing and the rest,
Washington will be impressed and may look with more favor on an
advanced X-15 or the X-15B.”
That remark was typical of Stormy. He was always looking far down the
pike. He had cornered the Air Force combat aircraft market with the
F-108 and the B-70, but he was stung when we lost out on the X-15B.
He had not given up--and never would.
“Frankly, Scotty,” Charlie Feltz broke in, “this engine thing may be
a blessing in disguise. I’ll tell you honestly that all along I’ve
been a little concerned about busting into space all at once with a
brand-new airplane and a brand-new, untried engine. They did it with
the X-1, it’s true, and it was a real good show. But this is a new
dimension we’re getting into. They were just trying to crack Mach 1.
We’re trying to crack space, with a new pressure suit, re-entry, new
metal, landing--everything at once. I’ve got a real good buddy who’s
going to be flying that airplane for the first time, and I’d just as
soon have him around for a while.”
Put that way, on a personal basis, there was nothing I could say
in reply. From that point on, I resigned myself to the engine
substitution, even though, in a sense, it marred my dream to help
build and then fly the perfect airplane. In fact, after some weeks,
I came to believe that even from a pilot’s point of view the engine
substitution was wise. We could learn to crawl before we entered the
Olympic hundred-yard dash. I was confident that in time and with
God’s help we would eventually succeed with the big engine. There was
too much at stake to allow it to fall by the wayside.