_Wilting Straws in Plaster of Paris_
The impasse in the perfection of the full-pressure suit was primarily
in the restraining material or “tire” which holds the inflatable
rubber “inner tube” against the pilot’s skin. Many materials were
tested to keep the ballooning inner tube in place against the skin,
but each was so heavy and rigid that when the suit was in operation,
the pilot was trapped in a bulbous vise, unable to move his arms,
legs, or head. The suit engineers tried to offset this by hinging
the elbow, neck, wrist, and knee joints with bellows and bearings.
But the end result was a complicated, mechanical monster, obviously
unsatisfactory for a pilot working within the tight confines of an
airplane cockpit, and quite marginal if escape from the aircraft
became necessary.
David Clark’s suit number seven, which I had first tested in the
altitude chamber in Philadelphia in 1951, was an attempt to get away
from the “stiff” suit concept. It was a step in the right direction
but a long way from an operationally sound item. But if enough time
and effort are devoted to any technical problem, the solution will
come eventually. Obsessed with this new challenge, David Clark kept
plugging away, with Air Force support, and in time came up with the
answer.
He revealed it to me one day in his factory, not long after
we completed the X-15 mock-up inspection. After a tour of his
fascinating plant we went to his private office. I could tell that he
was bursting with pride.
“Scotty,” he said, “did you ever see one of those ‘Chinese fingers’
made of straw? You know, those things you put your index finger in?
You try to pull your finger out and the straw grips it even tighter?”
“Yeah, sure,” I said. “I used to play with those when I was a kid.”
“Well, take a look at this. I made this on an airplane when I was
going up to Alaska last month to see my daughter.” He passed me a
sample of hand-woven material which looked not like a Chinese finger
but something like an Anchor Fence, except that it was made of nylon
thread. I gave it a good pull and right off I saw what he was driving
at.
“We call this ‘link-net’ material in the trade,” Clark said. “I think
it’s the answer to the pressure-suit restraining cloth. It will work
just like the Chinese finger. If you bend your arm, the material on
top will contract and the material on the bottom will stretch. It
also twists easily from side to side under stress. At all times you
will have an even pressure on the rubber bladders. It’s as flexible
as cotton cloth, strong as steel, and weighs little or nothing.
I think that with this material and the new regulators and other
improvements we can give you a complete full-pressure suit with a
total weight of thirty-five pounds.”
“What?” I was astonished. At best, present equipment for the job
added up to as much as 110 pounds, give or take a few.
“Yes, thirty-five. Now it’s going to take a little time because we
have to make this stuff by hand. But maybe we can come up with a
machine to weave it.”
Our long-standing faith in David Clark had paid off. The link-net
material proved to be the great “break-through” in the full-pressure
suit game. It relegated all the stiff suits to the junk-heap. The
restraining material was as flexible as a suit of long-johns and
almost as comfortable. It eliminated the need for bellows-joints at
the knees and elbows and for bearings at the shoulders and wrists.
As I was leaving the factory we passed through the Research
Department. Amid the great humming looms and rattling sewing
machines, I spotted a piece of shiny cloth lying on a long table. The
material looked somewhat like silver lamé. I went over and picked it
up.
“What is this?” I asked Clark.
“That’s a piece of nylon with a vacuum-blasted aluminum coating. Just
something one of the boys was trying out.”
“Pretty glamorous looking.”
Then a light went on in the back of my mind. “Say, Dave, why don’t
you make the outer cover of the pressure suit out of this material,
in place of that awful-looking khaki coverall?”
“Whatever for?”
“You remember that time down at Philadelphia when they took that
picture for the magazine cover? We don’t want to make that mistake
again. A coverall of this material would look real good, like a
space suit should--photogenic. To justify it technically we can tell
them this silver material is specially designed to radiate heat or
something.”
“A marvelous idea, Scotty. I’ll make the boots and gloves out of
black material for contrast.”
“Great touch,” I said. Ever since then all pressure suits have been
silver.
* * * * *
I made my way to New York City. To save his fitters expensive,
time-consuming cross-country trips each time they modified or
improved the new suit, Clark suggested that we mold a “statue” of me
just as I would sit in the cockpit of the X-15. I bought the idea
without a second thought. How I lived to regret it! Believe me, no
one can claim to have lived the full life until he has been cast in
plaster of Paris.
The appointment Dave Clark arranged in New York took me to a
ratty building on 42nd Street just off Broadway. John Flagg, now
a vice president of the Clark Company, met me, and together we
took a squeaky elevator to the studio of a theatrical sculptor.
He specialized in devices for stage sets, armor suits, horribly
distorted masks, and the like. The proprietor, a tall, balding man
with a walrus mustache, was a “mad artist,” a Romanian whose name I
have forgotten. He had an assistant, just off the boat and unable
to speak English. The studio turned out to be a cluttered, unheated
attic. It was mid-winter.
“Very well,” the artist said, rubbing his hands from the cold, or the
unexpected windfall, or the artistic challenge standing before him,
I’m not sure which. “We’ll make a plaster of Paris mold in two parts,
the body and the head. Later we will cast the statue in this mold.
Now first you must strip down completely and shave all the hair off
your body except your head.”
“_All_ the hair off my body?” I asked incredulously.
“Yes,” the artist replied. “_All_ of it. Otherwise, it will stick in
the plaster of Paris.”
“I don’t have a razor,” I said feebly, eyeing the nearest exit.
“Never mind, Scotty, I’ll go get one,” John Flagg said, chuckling.
He ran down the stairway and in a few minutes was back with a small
electric razor, the size used by ladies.
“I don’t know how in hell I’ll ever explain this on my expense
account,” he said, “but here it is.”
I stripped, put on an athletic supporter, and shaved the exposed
portions of my body. After applying a thick coating of vaseline to my
skin, I sat down on a rickety chair, feeling like a half-frozen Greek
god. The mad artist prepared the plaster of Paris mixture, screaming
in Romanian and gesticulating wildly at his assistant, pausing at his
work only to stand back to size up his victim. I noted with dismay
the ripples on my stomach in a sitting position. I would be cast
forever with a row of rubber tires on my waist!
The artists erected a mold about my body and then, without warning,
began slapping on the frigid plaster of Paris. At the beginning
it felt like being immersed in ice water, but as time passed my
sealed-off body heat began to build up, and for the first time since
I entered the attic I was warm. But soon I was too hot, sweating and
breathing heavily under the increasing load of plaster.
The artists erected a cage of steel within the plaster to hold it
together. Then they turned me upside down in the chair and did the
other side. I waited in stolid agony for the plaster to harden,
afraid to move a muscle lest the mold be ruined and the process
repeated.
“Now we must do the head,” the artist said. “This is the most
difficult part. You’re not subject to claustrophobia, are you? Do you
prefer to breathe through your nose or mouth?”
“Mouth,” I said. “No, I don’t have claustrophobia.”
The creation of the head mold was slightly different but no less
taxing. First they covered me with a kind of rubbery moulage, and
after putting two paper straws in my mouth so I could breathe, they
then applied the plaster. After a few minutes the straws wilted
and I could barely suck in enough air for survival. I couldn’t
swallow because the movement of my Adam’s apple would destroy their
work. With my head rigidly set in the heavy mold, I listened as
the artists babbled. Their voices seemed to come from far away,
from some deep cave. They watched me closely. With their heads so
encased, some people become overwhelmed by claustrophobia and come up
fighting--ripping at the mask.
John Flagg was doubled up on the floor with laughter.
Before applying the plaster over the rubbery moulage, the two artists
had laid a string across my head from shoulder to shoulder. The idea
was that when the mold hardened it could be cut in two and thus
removed by pulling the string, something like opening a package of
chewing gum or cigarettes.
Now a great debate arose between the two artists about when to pull
the string. Actually, this _is_ a matter for careful consideration
because the string must be pulled at exactly the right time. If it is
pulled too soon, before the plaster has hardened enough, the whole
thing crumbles, or the seam rejoins. If it is pulled too late, after
the plaster becomes hard and brittle, the mask must be chiseled off
and the process begun all over again.
In the midst of the debate, the head artist remembered he had to make
an urgent telephone call. He disappeared from the room, leaving
his assistant to watch over the victim. It was clear from muffled
conversation that the assistant was very concerned. He touched the
plaster repeatedly, testing its hardness, shook his head glumly and
paced the floor, obviously as torn by indecision as Hamlet. Finally,
he could stand it no longer. He rushed over and pulled the string.
A few moments later the chief artist returned and smilingly said:
“Well, now, it is time to pull the string.” Then with a look of
horror he saw that he had been beaten to the punch. He exploded and
turned on the assistant in fury, babbling in Romanian, English, and,
I think, six other languages.
“I’ll fire you--you don’t know anything about this work--I’ll have
your visa revoked--you’ll go home on the next boat--” And so on.
The mold held together, after all. It was finally removed and I could
breathe again. I tried to wash the vaseline coating from my body with
cold water, and then I got out of there as fast as I could.
As it turned out, the crazy artist made a fairly creditable statue
from the mold and my rubber tires were immortally preserved. Clark
used the statue to make number one and number two X-15 pressure
suits. As far as the fit was concerned, they were perfect as long as
I didn’t gain a pound.
* * * * *
After that I spent the equivalent of years of flying in the Air
Force’s altitude and test chambers at Wright Field testing the Clark
pressure suits. The Air Force people--notably the Command Flight
Surgeon of the Air Research and Development Command, Brigadier
General Don Flickinger--displayed keen interest in the work and
their support was unlimited. We wrung out the suits, not only in
repeated “trips” to 150,000 feet altitude, but also in ovens and
refrigerators, to make sure they, to say nothing of the pilot, could
stand up under extremes of temperature.
These prolonged tests became somewhat of a minor physical challenge
for me. The aero-medical officers at Wright Field submitted, half
jokingly, that considering my age (I was then 36) my body would never
take the beating. When they matched my performance against the data
accumulated on human guinea pigs over several years, my record defied
their statistics.
“You’re a physical freak,” someone remarked. “No one can take that
kind of punishment. How do you do it?”
It seemed superfluous to point out that for centuries man has been
outperforming and outliving the statistics of the physicians, and
that, as I have said before, if the spirit is willing the flesh can
exceed all probable limits. History is full of such accounts. Teddy
Roosevelt is a good example.
* * * * *
The sled track at Edwards was the brain-child of Air Force Colonel
John Paul Stapp, an aero-medical officer who specialized in the
physiological effects of high-speed and high-altitude bail out and
severe G forces. The track was a mile long. The sled was powered by
a cluster of solid-propellant rockets. When touched off, the sled
accelerated with great speed. It roared down the track for a few
seconds and then splashed into a pool of water. The water stopped
the sled, subjecting it to tremendous G. On the front of the sled
we mounted a dummy nose of the X-15, complete with cockpit canopy,
ejection seat, and a plastic anthropomorphic form in the seat dressed
in a Clark pressure suit.
We gathered behind a concrete shield listening as the countdown was
intoned on the loudspeaker: “5 ... 4 ... 3 ... 2 ... 1 ... Zero!”
The powerful rockets on the rear of the sled exploded to life. Within
a few seconds the big sled was hurtling down the track at 1000 miles
an hour, almost faster than the eye could follow. Cameras, mounted in
a half-dozen positions, recorded the motion of the sled and the X-15
nose. Sensitive instruments on the seat and inside the plastic dummy
telemetered back a constant stream of data. These data would tell us
the total effect of wind-blast and heat on the dummy and pressure
suit. It would settle once and for all the controversy of the X-15
ejection-seat principle.
At the peak of acceleration of the sled--1000 miles an hour--the
X-15 seat fired automatically. The V-shaped canopy blew off. The
seat, with the dummy firmly restrained, rose from the sled and
zoomed skyward. Over one hundred feet in the air the dummy separated
from the seat and a parachute automatically deployed, lowering the
pressure-suit-clad dummy to the desert floor. The parachute was a
lightweight model with a twenty-four-foot canopy, built and tested
especially for the X-15.
The test was successful. To make certain we were right, we ran the
sled several more times. All the data indicated the X-15 pilot,
protected by a Clark full-pressure suit, could eject under the most
severe conditions we could anticipate without bodily injury beyond
the usual bruises associated with an escape from a disabled airplane.
* * * * *
“Charlie,” I said, pulling a chair alongside Feltz’s desk. “Here is
the final word on the suit as we see it.” I laid out a series of
reports and schematic drawings.
“The basic deal is this: the first layer is winter underwear, the
second a ventilation garment to cool the pilot. The third layer is
the rubberized airtight pressure garment with the anti-G bladders.
The fourth layer is this new link-net material for strength. The
outer layer is this silver lamé material, mainly for photo appeal.
“We have run the suit through heat and cold tests. It will withstand
anything we can expect to meet. The suit itself, during X-15
flight, will be cooled by nitrogen gas from the same tank we use to
pressurize the X-15 cockpit; you’ll hardly be able to measure the
quantity. Here’s the way we have the oxygen regulators and supply set
up. During ride to launch point the pilot in the suit breathes oxygen
from a supply from the mother plane. When he’s ready to launch, he
can turn a valve and get oxygen from a supply in the X-15. This will
save us some oxygen weight. The suit itself contains a bottle of
oxygen, enough to get him down on the ground, which automatically
pressurizes the suit and helmet in case of ejection. Incidentally,
we’ve got a rubber seal in the helmet just above the pilot’s mouth
and nose to prevent fogging the helmet lens. No electrical heating
required.
“We worked it so that the parachute harness also serves as the
seat-restraint straps. No need for extra shoulder straps and a lap
belt. This will save us a few pounds. The sled tests show that the
manacles will hold the pilot’s feet in place, and that the blast on
ejection is far from fatal. The seat weather-vanes, as expected. The
pilot will pull some G’s going out, but not enough to black him out.
Now, to top it all off, I’m giving you the whole pressure suit for
thirty-nine pounds. You could walk around in it on the moon.”
“Dad-gummed,” Feltz said. “This sounds too good to be true. Where’s
the hooker?”
“The only problem is this. We’re still ironing out some improvements.
We can’t go much faster than we’re going. I’m afraid that’s the way
it’s going to wind up. We will be flight-testing the new pressure
suit and the X-15 all at the same time.”
“You won’t be able to flight-test the suit before then?”
“No,” I said. “We’ll have a lot of chamber time, but no realistic
in-flight operations.”
“Well, that’s the breaks,” Feltz said. “Just make darned sure the
thing works.”