- Ryan, Craig.
Sonic Wind.
New York: Livewright Publishing, 2018.
ISBN 978-0-631-49191-0.
-
Prior to the 1920s, most aircraft pilots had no means of escape
in case of mechanical failure or accident. During World War I,
one out of every eight combat pilots was shot down or killed in
a crash. Germany experimented with cumbersome parachutes stored
in bags in a compartment behind the pilot, but these often
failed to deploy properly if the plane was in a spin or became
tangled in the aircraft structure after deployment. Still, they
did save the lives of a number of German pilots. (On the other
hand, one of them was Hermann Göring.) Allied pilots were
not issued parachutes because their commanders feared the loss
of planes more than pilots, and worried pilots would jump rather
than try to save a damaged plane.
From the start of World War II, military aircrews were
routinely issued parachutes, and backpack or seat pack
parachutes with ripcord deployment had become highly
reliable. As the war progressed and aircraft performance
rapidly increased, it became clear that although parachutes
could save air crew, physically escaping from a damaged plane
at high velocities and altitudes was a
formidable problem. The U.S.
P-51
Mustang, of which more than 15,000 were built, cruised at
580 km/hour and had a maximum speed of 700 km/hour. It was
physically impossible for a pilot to escape from the cockpit
into such a wind blast, and even if they managed to do so,
they would likely be torn apart by collision with the fuselage or
tail an instant later. A pilot's only hope was that the plane
would slow to a speed at which escape was possible before
crashing into the ground, bursting into flames, or disintegrating.
In 1944, when the Nazi Luftwaffe introduced the first
operational jet fighter, the
Messerschmitt
Me 262, capable of 900 km/hour flight,
they experimented with explosive-powered
ejection
seats, but never installed them in this front-line fighter.
After the war, with each generation of jet fighters flying
faster and higher than the previous, and supersonic performance
becoming routine, ejection seats became standard equipment in
fighter and high performance bomber aircraft, and saved many
lives. Still, by the mid-1950s, one in four pilots who tried to
eject was killed in the attempt. It was widely believed that
the forces of blasting a pilot out of the cockpit, rapid
deceleration by atmospheric friction, and wind blast at
transonic and supersonic speeds were simply too much for the
human body to endure. Some aircraft designers envisioned
“escape capsules” in which the entire crew cabin
would be ejected and recovered, but these systems were seen to
be (and proved when tried) heavy and potentially unreliable.
John Paul Stapp's family came from the Hill Country of
south central Texas, but he was born in Brazil in 1910
while his parents were Baptist missionaries there. After
high school in Texas, he enrolled in Baylor University
in Waco, initially studying music but then switching
his major to pre-med. Upon graduation in 1931 with a
major in zoology and minor in chemistry, he found that
in the depths of the Depression there was no hope of
affording medical school, so he enrolled in an M.A.
program in biophysics, occasionally dining on pigeons he
trapped on the roof of the biology building and grilled
over Bunsen burners in the laboratory. He then entered
a Ph.D. program in biophysics at the University of
Texas, Austin, receiving his doctorate in 1940. Before
leaving Austin, he was accepted by the medical school
at the University of Minnesota, which promised him
employment as a research assistant and instructor to
fund his tuition.
In October 1940, with the possibility that war in Europe and
the Pacific might entangle the country, the U.S. began
military conscription. When the numbers were drawn from
the fishbowl, Stapp's was 15th from the top. As a
medical student, he received an initial deferment,
but when it expired he joined the regular Army under
a special program for medical students. While
completing medical school, he would receive private's
pay of US$ 32 a month (around US$7000 a year in today's
money), which would help enormously with tuition and
expenses. In December 1943 Stapp received his M.D.
degree and passed the Minnesota medical board examination.
He was commissioned as a second lieutenant in the
Army Medical Corps and placed on suspended active duty
for his internship in a hospital in Duluth, Minnesota,
where he delivered 200 babies and assisted in 225
surgeries. He found he delighted in emergency and
hands-on medicine. In the fall of 1944 he went on full
active duty and began training in field medicine. After
training, he was assigned as a medical officer at
Lincoln Army Air Field in Nebraska, where he would
combine graduate training with hospital work.
Stapp had been fascinated by aviation and the exploits
of pioneers such as Charles Lindbergh and the stratospheric
balloon explorers of the 1930s, and found working at an
air base fascinating, sometimes arranging to ride along
in training missions with crews he'd treated in the hospital.
In April 1945 he was accepted by the Army School of Aviation
Medicine in San Antonio, where he and his class of 150
received intense instruction in all aspects of human
physiology relating to flight. After graduation and
a variety of assignments as a medical officer, he was
promoted to captain and invited to apply to the Aero Medical
Laboratory at Wright Field in Dayton, Ohio for a research
position in the Biophysics Branch. On the one hand, this
was an ideal position for the intellectually curious Stapp,
as it would combine his Ph.D. work and M.D. career. On
the other, he had only eight months remaining in his
service commitment, and he had long planned to leave the
Army to pursue a career as a private physician. Stapp
opted for the challenge and took the post at Wright.
Starting work, he was assigned to the pilot escape technology
program as a “project engineer”. He protested,
“I'm a doctor, not an engineer!”, but settled
into the work and, being fluent in German, was assigned to
review 1200 pages of captured German documents relating to
crew ejection systems and their effects upon human subjects.
Stapp was appalled by the Nazis' callous human experimentation,
but, when informed that the Army intended to destroy the
documents after his study was complete, took the initiative
to preserve them, both for their scientific content and as
evidence of the crimes of those whose research produced it.
The German research and the work of the branch in which Stapp
worked had begun to persuade him that the human body was far
more robust than had been assumed by aircraft designers and
those exploring escape systems. It was well established by
experiments in centrifuges at Wright and other laboratories that
the maximum long-term human tolerance for acceleration (g-force) without
special equipment or training was around six times that of
Earth's gravity, or 6 g. Beyond that, subjects would lose
consciousness, experience tissue damage due to lack of blood
flow, or structural damage to the skeleton and/or internal
organs. However, a pilot ejecting from a high performance
aircraft experienced something entirely different from a subject
riding in a centrifuge. Instead of a steady crush by, say, 6 g,
the pilot would be subjected to much higher accelerations,
perhaps on the order of 20—40 g, with an onset of
acceleration
(“jerk”)
of 500 g per second. The initial blast of the mortar or rockets
firing the seat out of the cockpit would be followed by a
sharp pulse of deceleration as the pilot was braked from
flight speed by air friction, during which he would be
subjected to wind blast potentially ten times as strong as
any hurricane. Was this survivable at all, and if so, what
techniques and protective equipment might increase a pilot's
chances of enduring the ordeal?
While pondering these problems and thinking about ways to
research possible solutions under controlled conditions,
Stapp undertook another challenge: providing supplemental
oxygen to crews at very high altitudes. Stapp volunteered
as a test subject as well as medical supervisor and
began flight tests with a liquid oxygen
breathing system on high altitude B-17 flights. Crews flying
at these altitudes in unpressurised aircraft during World
War II and afterward had frequently experienced symptoms
similar to
“the
bends” (decompression sickness) which struck divers
who ascended too quickly from deep waters. Stapp diagnosed
the cause as identical: nitrogen dissolved in the blood coming
out of solution as bubbles and pooling in joints and other
bodily tissues. He devised a procedure of oxygen pre-breathing,
where crews would breathe pure oxygen for half an hour before
taking off on a high altitude mission, which completely
eliminated the decompression symptoms. The identical procedure
is used today by astronauts before they begin extravehicular
activities in space suits using pure oxygen at low pressure.
From the German documents he studied, Stapp had become
convinced that the tool he needed to study crew escape was a
rocket propelled sled, running on rails, with a brake mechanism
that could be adjusted to provide a precisely calibrated
deceleration profile. When he learned that the Army was
planning to build such a device at Muroc Army Air Base
in California, he arranged to be put in charge of Project MX-981
with a charter to study the “effects of deceleration
forces of high magnitude on man”. He arrived at Muroc in
March 1947, along with eight crash test dummies to be used in
the experiments. If Muroc (now Edwards Air Force Base) of the
era was legendary for its Wild West accommodations (Chuck Yeager
would not make his first supersonic flight there until October
of that year), the North Base, where Stapp's project was
located, was something out of Death Valley Days. When Stapp arrived
to meet his team of contractors from Northrop Corporation they
struck the always buttoned-down Stapp like a “band of
pirates”. He also discovered the site had no electricity, no running
water, no telephone, and no usable buildings. The Army,
preoccupied with its glamourous high speed aviation projects, had
neither interest in what amounted to a rocket powered train with
a very short track, nor much inclination to provide it the
necessary resources. Stapp commenced what he came to call
the Battle of Muroc, mastering the ancient military art of
scrounging and exchanging favours to get the material he
needed and the work done.
As he settled in at Muroc and became acquainted with his fellow
denizens of the desert, he was appalled to learn that the
Army provided medical care only for active duty personnel,
and that civilian contractors and families of servicemen,
even the exalted test pilots, had to drive 45 miles to the
nearest clinic. He began to provide informal medical care to
all comers, often making house calls in the evening hours on
his wheezing scooter, in return for home cooked dinners. This
built up a network of people who owed him favours, which he
was ready to call in when he needed something. He called
this the “Curbstone Clinic”, and would continue
the practice throughout his career. After some shaky starts
and spectacular failures due to unreliable surplus JATO
rockets, the equipment was ready to begin experiments with
crash test dummies.
Stapp had always intended that the tests with dummies would be
simply a qualification phase for later tests with human and
animal subjects, and he would ask no volunteer to do something
he wouldn't try himself. Starting in December, 1947, Stapp
personally made increasingly ambitious runs on the sled,
starting at “only” 10 g deceleration and building to
35 g with an onset jerk of 1000 g/second. The runs left him
dizzy and aching, but very much alive and quick to recover.
Although far from approximating the conditions of ejection from
a supersonic fighter, he had already demonstrated that the Air
Force's requirements for cockpit seats and crew restraints,
often designed around a 6 g maximum shock, were inadequate and
deadly. Stapp was about to start making waves, and some of the
push-back would be daunting. He was ordered to cease all human
experimentation for at least three months.
Many Air Force officers (for the Air Force had been founded in
September 1947 and taken charge of the base) would have saluted
and returned to testing with instrumented dummies. Stapp,
instead, figured out how to obtain thirty adult chimpanzees,
along with the facilities needed to house and feed them, and
resumed his testing, with anæsthetised animals, up to
the limits of survival. Stapp was, and remained throughout his
career, a strong advocate for the value of animal
experimentation. It was a grim business, but at the time
Muroc was frequently losing test pilots at the rate of one
a week, and Stapp believed that many of these fatalities were
unnecessary and could be avoided with proper escape and
survival equipment, which could only be qualified through animal
and cautious human experimentation.
By September 1949, approval to resume human testing was given,
and Stapp prepared for new, more ambitious runs, with the
subject facing forward on the sled instead of backward as before,
which would more accurately simulate the forces in an ejection or
crash and expose him directly to air blast. He rapidly ramped up
the runs, reaching 32 g without permanent injury. To
avoid alarm on the part of his superiors in Dayton, a “slight
error” was introduced in the reports he sent: all
g loads from the runs were accidentally divided by two.
Meanwhile, Stapp was ramping up his lobbying for safer seats in
Air Force transport planes, arguing that the existing 6 g
forward facing seats and belts were next to useless in many
survivable crashes. Finally, with the support of twenty
Air Force generals, in 1950 the Air Force adopted a new
rear-facing standard seat and belt rated for 16 g which weighed
only two pounds more than those it replaced. The 16 g requirement
(although not the rearward-facing orientation, which proved
unacceptable to paying customers) remains the standard for
airliner seats today, seven decades later.
In June, 1951, Stapp made his final run on the MX-981 sled
at what was now Edwards Air Force Base, decelerating from
180 miles per hour (290 km/h) to zero in 31 feet (9.45
metres), at 45.4 g, a force comparable to many aircraft
and automobile accidents. The limits of the 2000 foot
track (and the human body) had been reached. But Stapp was
not done: the frontier of higher speeds remained. Shortly
thereafter, he was promoted to lieutenant colonel and
given command of what was called the Special Projects
Section of the Biophysics Branch of the Aero Medical
Laboratory. He was reassigned to Holloman Air Force Base
in New Mexico, where the Air Force was expanding its
existing 3500 foot rocket sled track to 15,000 feet
(4.6 km), allowing testing at supersonic speeds.
(The
Holloman
High Speed Test Track remains in service today, having been
extended in a series of upgrades over the years to a total of
50,917 feet (15.5 km) and a maximum speed of Mach 8.6, or
2.9 km/sec [6453 miles per hour].)
Northrop was also contractor for the Holloman sled, and
devised a water brake system which would be more reliable
and permit any desired deceleration profile to be
configured for a test. An upgraded instrumentation system would
record photographic and acceleration measurements with
much better precision than anything at Edwards. The
new sled was believed to be easily capable of supersonic
speeds and was named Sonic Wind. By March
1954, the preliminary testing was complete and Stapp
boarded the sled. He experienced a 12 g acceleration
to the peak speed of 421 miles per hour, then 22 g
deceleration to a full stop, all in less than eight seconds.
He walked away, albeit a little wobbly. He had easily
broken the previous land speed record of 402 miles per hour
and become “the fastest man on Earth.” But
he was not done.
On December 10th, 1954, Stapp rode Sonic Wind,
powered by nine solid rocket motors. Five seconds later,
he was travelling at 639 miles per hour, faster than the
.45 ACP round fired by the M1911A1 service pistol he was
issued as an officer, around Mach 0.85 at the elevation of
Holloman. The water brakes brought him to a stop in 1.37
seconds, a deceleration of 46.2 g. He survived, walked
away (albeit just few steps to the ambulance), and although
suffering from vision problems for some time afterward,
experienced no lasting consequences. It was estimated
that the forces he survived were equivalent to those from
ejecting at an altitude of 36,000 feet from an airplane
travelling at 1800 miles per hour (Mach 2.7). As this
was faster than any plane the Air Force had in service or
on the drawing board, he proved that, given a suitable
ejection seat, restraints, and survival equipment, pilots
could escape and survive even under these extreme
circumstances. The Big Run, as it came to be called, would
be Stapp's last ride on a rocket sled and the last human
experiment on the Holloman track. He had achieved the
goal he set for himself in 1947: to demonstrate that crew
survival in high performance aircraft accidents was a
matter of creative and careful engineering, not the limits
of the human body. The manned land speed record set on the
Big Run would stand until October 1983, when Richard
Noble's jet powered
Thrust2
car set a new record of 650.88 miles per hour in the
Nevada desert. Stapp remarked at the time that Noble had
gone faster but had not, however, stopped from that speed
in less than a second and a half.
From the early days of Stapp's work on human tolerance to
deceleration, he was acutely aware that the forces experienced
by air crew in crashes were essentially identical to those in
automobile accidents. As a physician interested in public
health issues, he had noted that the Air Force was losing more
personnel killed in car crashes than in airplane accidents. When
the Military Air Transport Service (MATS) adopted his
recommendation and installed 16 g aft-facing seats in its
planes, deaths and injuries from crashes had fallen by
two-thirds. By the mid 1950s, the U.S. was suffering around
35,000 fatalities per year in automobile
accidents—comparable to a medium-sized war—year in
and year out, yet next to nothing had been done to make
automobiles crash resistant and protect their occupants in case
of an accident. Even the simplest precaution of providing lap
belts, standard in aviation for decades, had not been taken;
seats were prone to come loose and fly forward even in mild
impacts; steering columns and dashboards seemed almost designed
to impale drivers and passengers; and “safety” glass
often shredded the flesh of those projected through it in a
collision.
In 1954, Stapp turned some of his celebrity as the fastest man
on Earth toward the issue of automobile safety and organised, in
conjunction with the Society of Automotive Engineers (SAE), the
first Automobile Crash Research Field Demonstration and
Conference, which was attended by representatives of all of the
major auto manufacturers, medical professional societies, and
public health researchers. Stapp and the SAE insisted that the
press be excluded: he wanted engineers from the automakers free
to speak without fear their candid statements about the safety
of their employers' products would be reported sensationally.
Stapp conducted a demonstration in which a car was towed into a
fixed barrier at 40 miles an hour with two dummies wearing
restraints and two others just sitting in the seats. The belted
dummies would have walked away, while the others flew into the
barrier and would have almost certainly been killed. It was at
this conference that many of the attendees first heard the term
“second collision”. In car crashes, it was often
not the crash of the car into another car or a barrier that
killed the occupants: it was their colliding with dangerous
items within the vehicle after flying loose following the
initial impact.
Despite keeping the conference out of the press, word of
Stapp's vocal advocacy of automobile safety quickly
reached the auto manufacturers, who were concerned both
about the marketing impact of the public becoming aware
not only of the high level of deaths on the highways but
also the inherent (and unnecessary) danger of their
products to those who bought them, and also the
bottom-line impact of potential government-imposed safety
mandates. Auto state congressmen got the message, and
the Air Force heard it from them: the Air Force threatened
to zero out aeromedical research funding unless car crash
testing was terminated. It was.
Still, the conferences continued (they would eventually
be renamed “Stapp Car Crash Conferences”), and Stapp
became a regular witness before congressional committees
investigating automobile safety. Testifying about whether
it was appropriate for Air Force funds to be used in studying
car crashes, in 1957 he said, “I have done autopsies
on aircrew members who died in airplane crashes. I have
also performed autopsies on aircrew members who died in
car crashes. The only conclusion I could come to is that
they were just as dead after a car crash as they were
after an airplane crash.” He went on to note
that simply mandating seatbelts in Air Force ground
vehicles would save around 125 lives a year, and if they
were installed and used by the occupants of all cars in
the U.S., around 20,000 lives—more than half the
death toll—could be saved. When he appeared
before congress, he bore not only the credentials of
a medical doctor, Ph.D. in biophysics, Air Force colonel,
but the man who had survived more violent decelerations
equivalent to a car crash than any other human.
It was not until the 1960s that a series of mandates
were adopted in the U.S. which required seat belts,
first in the front seat and eventually for all passengers.
Testifying in 1963 at a hearing to establish a National
Accident Prevention Center, Stapp noted that the Air Force,
which had already adopted and required the use of seat
belts, had reduced fatalities in ground vehicle accidents
by 50% with savings estimated at US$ 12 million per year.
In September 1966, President Lyndon Johnson signed two
bills, the National Traffic and Motor Vehicle Safety
Act and the Highway Safety Act, creating federal agencies
to research vehicle safety and mandate standards. Standing
behind the president was Colonel John Paul Stapp: the
long battle was, if not won, at least joined.
Stapp had hoped for a final promotion to flag rank before
retirement, but concluded he had stepped on too many toes
and ignored too many Pentagon directives during his career
to ever wear that star. In 1967, he was loaned by the Air Force
to the National Highway Traffic Safety Administration to
continue his auto safety research. He retired from the
Air Force in 1970 with the rank of full colonel and in
1973 left what he had come to call the “District
of Corruption” to return to New Mexico. He continued
to attend and participate in the Stapp Car Crash Conferences,
his last being the Forty-Third in 1999. He died at his
home in Alamogordo, New Mexico in November that year at
the age of 89.
In his later years, John Paul Stapp referred to the survivors
of car crashes who would have died without the equipment
designed and eventually mandated because of his research as
“the ghosts that never happened”. In 1947, when
Stapp began his research on deceleration and crash survival,
motor vehicle deaths in the U.S. were 8.41 per 100 million
vehicle miles travelled (VMT). When he retired from the
Air Force in 1970, after adoption of the first round of
seat belt and auto design standards, they had fallen to
4.74 (which covers the entire fleet, many of which were
made before the adoption of the new standards). At the time of
his death in 1999, fatalities per 100 million VMT were 1.55,
an improvement in safety of more than a factor of five.
Now, Stapp was not solely responsible for this, but it was
his putting his own life on the line which showed that
crashes many considered “unsurvivable” were
nothing of the sort with proper engineering and knowledge
of human physiology. There are thousands of aircrew and
tens or hundreds of thousands of “ghosts that never
happened” who owe their lives to John Paul Stapp. Maybe
you know one; maybe you are one. It's worth a moment
remembering and giving thanks to the largely forgotten man
who saved them.
February 2020 