Smoking Ears and Screaming Teeth - Trevor Norton (2010)

High, Fast and Hazardous

‘Eyeballs in, eyeballs out’ – One consequence of rapid acceleration and abrupt deceleration

Auguste Piccard was sixty-nine when he dived in the bathyscaphe. He had already been immortalised as the lanky professor with feral hair in the adventures of Tintin. Being ambidextrous he could draw a different diagram with each hand simultaneously. Piccard was also bidirectional. He had been to the bottom of the ocean and had also risen into the stratosphere in a balloon. It takes little imagination to realise that the bathyscaphe was just a balloon that sank. As with a balloon the float was an envelope to provide lift, and ballast was dropped to slow or halt the descent.

Auguste had served in the lighter-than-air service during the First World War. Over a decade later he became interested in cosmic rays – the remnants of the Big Bang at the birth of the universe. These rays are nuclear particles that come from outer space. In their passage through the Earth’s atmosphere they are modified and lose energy by colliding with other particles. At ground level they contribute little to a person’s exposure to radiation but, at the altitude where aircraft fly, cosmic rays become the predominant source of radiation. Auguste wanted to study ‘virgin’ rays before they were modified. To do this he had to monitor them in the stratosphere.

Venturing to such high altitudes was a risky business, as other researchers had found. In 1862 James Glaisher, a distinguished meteorologist, accompanied by a celebrity balloonist called Henry Coxwell, ascended from Wolverhampton gasworks. The giant balloon had been specially commissioned for scientific research. Glaisher took seventeen scientific instruments to measure humidity and temperature. At an altitude of 8,850 metres his vision became too blurred to read his instruments. Soon his limbs and neck were becoming paralysed and he could no longer speak. They were still rising. Cox climbed up to try to vent hydrogen from the balloon so they could descend, but his hands froze to the metal ring above the basket. He managed to pull the cord with his teeth and saved their lives. They had risen to 11,278 metres – higher than anyone had been before.

On the descent Glaisher recovered and resumed his observations. Undeterred by the adventure he made twenty-eight further ascents. Glaisher was able to show that the higher they went in the atmosphere, the less moisture was present and that the air temperature did not decline uniformly with altitude. The stratosphere was as turbulent as the sea.

In 1875 another ill-fated aerial expedition took off from Paris. It carried three engineers and scientists set on examining the upper atmosphere. Gaston Tissandier, Joseph Sivel and Theodore Croce-Spinelli ascended in a balloon. As they rose they took their pulse and breathing rates. Sivel’s heart was beating at almost double the normal rate. At 7,500 metres Sivel suggested they should go higher and the others agreed. They released some ballast and busied themselves taking readings from their barometers, thermometers and spectroscope. The balloon rose rapidly to 8,600 metres and they lost consciousness. Tissandier and later Croce-Spinelli awoke briefly and were so befuddled that they both released more ballast.

When Tissandier came round an hour and a half later, they were at 6,000 metres and falling. Both his colleagues were dead from a lack of oxygen.

In preparation for the flight they had spent time in a low-pressure chamber in the laboratory of Paul Bert who was a world authority on pressure. It convinced them of the importance of breathing oxygen. It would enable them to go even higher than they had planned. They took with them three balloons, about the size of beach balls, filled with seventy per cent oxygen. Bert wrote to them stressing that it was nowhere near enough. They each had only six minutes’ supply for a flight on which almost two and a half hours would be spent at altitudes where it was essential. It was too late to get more. The short supply led them to keep it until it was absolutely necessary. By the time Tissandier felt the need for oxygen he was too far gone to reach the mouthpiece.

Gradual oxygen depletion is an insidious killer. As Tissandier wrote, ‘One feels an inner joy … one becomes indifferent and thinks no more of the perilous situation.’ Slow depressurisation in aircraft has led to bizarre accidents in which planes on autopilot have flown on, with all the crew and passengers comatose, until the fuel runs out.

Piccard knew that the answer for his balloon was to have a pressurised cabin with its own oxygen supply. This was long before airplanes were pressurised. For him to study cosmic rays the cabin had to be non-magnetic and electrically neutral. Aluminium was the answer. The only factories that knew how to fashion aluminium were breweries. They assembled large panels to make vats. So brewery engineers shaped three large pieces of aluminium and welded them together to make a sphere. The walls were only 3.5 millimetres thick.

There were two manholes to allow access, with hatches on the inside. To make them airtight the hatch had to be bigger than the manhole. When Piccard came to inspect the finished sphere he noticed that the two hatches were lying on a bench. He pointed out that there was now no way of getting them into the sphere. A workman huffed and heaved and failed to push one through the hole. Yet on Piccard’s next visit the hatches were in place. He never discovered how they had done it.

There were also legal problems. For safety reasons the ballast for balloons had to be either sand or water. Piccard had lead shot. He listed it as ‘lead sand’ and all was well. To ensure that released shot would not injure people on the ground, Piccard stood at the bottom of a fifty-metre chimney under a rain of lead shot.

With the weight of the sphere, and because the air in the stratosphere is so thin, the hydrogen balloon had to be ten times bigger than a conventional hot-air balloon. It was over thirty-four metres in diameter. The project was funded by the Belgian research council and the balloon bore the council’s initials: FNRS. That is why much later the first bathyscaphe, funded by the same agency, was designated FNRS-2.

In May 1931 the giant balloon was inflated with hydrogen. A mischievous wind dislodged the sphere from its transporter, which made a tiny hole in the sphere that would endanger the lives of Piccard and his fellow scientist, Paul Kipfer. They had not given the signal to release the moorings when Kipfer saw the top of a factory chimney drifting past.

At an altitude of four kilometres Piccard was concerned to find that the pressure inside and outside the sphere was the same. There was a hiss of escaping gas. A wicker basket would have been as airtight. If they didn’t plug the hole, the mission would have to be aborted. Fortunately Piccard had anticipated this development and filled the hole with some ‘gunk’ that he had prepared earlier. At the second attempt the hissing stopped and the aeronauts enjoyed the reassuring silence.

Within half an hour they were at fifteen kilometres, penetrating into the sombre indigo sky of the stratosphere. After dropping ballast to rise further, they tried to vent a little hydrogen to control their ascent. The rope that allowed them to release hydrogen had jammed. When they tried to twist it free, it snapped. They were now unable to descend and were condemned to drift out of control until their oxygen ran out.

When they didn’t land at the scheduled time, the newspapers, with their appetite for bad news, reported:

PICCARD BALLOON DRIFTS HELPLESSLY ABOVE ALPS

Scientist feared dead

Not dead, but becoming increasingly nervous. Piccard bumped into their large barometer and its mercury poured out to pool on the floor of the sphere. Mercury can eat through aluminium. They hoped that the coating of paint wasn’t chipped. Then Piccard had a brilliant idea. He connected a length of tubing to a spigot that allowed access to the outside and the vacuum of space sucked up the mercury and spat it out.

At higher altitude the walls of the sphere became so cold that condensation inside the sphere turned to thick frost. It was like being trapped in a cave of ice. When the sun came up, it snowed. As the temperature rose they became parched and neither of them fancied drinking the soup of oil, mercury and water on the floor. Piccard made some water by pouring liquid oxygen into a metal cup and allowing it to evaporate, forming a layer of frost on the outside. It was perfectly drinkable once it had warmed from -212°C.

Piccard had painted one side of the sphere white and the other black so that by rotating it he could have either the heat-absorbing or heat-reflecting side facing the sun. Unfortunately, the rotating mechanism didn’t work.

The balloon had risen to 15,781 metres. Then, in the chill of the evening, the hydrogen in the envelope shrank and the balloon began to fall, slowly at first, then faster. They didn’t dare to slow it down by dropping ballast for fear that the balloon would rise out of control. The dying sun caught the curve of the balloon and observers on the ground discovered a new crescent moon.

Below them were the sharp pointed arêtes of the Alps. The sphere bounced like a pinball over a glacier with crevasses deep enough to swallow it whole. Spotting a snowfield beyond, Piccard pulled the strap of the balloon’s ripping panel to release all the hydrogen. The huge envelope collapsed around them. It made an ample counterpane under which they could sleep beneath the stars. Next morning Piccard woke in a panic. He thought the whisper of a distant waterfall was the hiss of escaping air.

Because Piccard and Kipfer spent so much time coping with emergencies they made only a perfunctory measurement of cosmic radiation. On his return Piccard immediately began work on a new sphere to return to the stratosphere. In August 1932 he ascended to a record altitude, only sixty metres short of seventeen kilometres. His sphere is now on display at the Science Museum at Wroughton in Wiltshire.

He showed that cosmic radiation was more intense in the stratosphere but not so great as had been suspected. Even at the maximum altitude he reached, relatively few high-energy particles penetrated into the sphere. He confirmed that astronauts could survive voyages into the high stratosphere and perhaps beyond, into outer space.

Auguste Piccard’s twin brother Felix later designed high-altitude balloons for the US Air Force that reached 30,000 metres. In 1999 his grandson Bertrand and Brian Jones were the first balloonists to circle the world. But Auguste wasn’t interested in records, not even his own.

Many records, such as the sound barrier, have been broken in the course of research for military purposes. During the Second World War German jet fighters just zipped away when a flight of Mustangs appeared. The US Air Force was determined never to be outpaced again.

At the end of the war a young fighter ace was posted to what is now called Wright Field, a US Air Force base in Ohio. Chuck Yeager became an Assistant Maintenance Officer. He and another ex-fighter pilot, Bob Hoover, were allowed to take up any of the assortment of aircraft on the base. Their forays were not without incident. Hoover had twenty or so aerial scrapes. One time, after his engine had failed, he deliberately bounced off the top of a truck in order to clear a fence. Not surprisingly, the resident test pilots considered them to be undisciplined cowboys. In contrast, they were college types, cool and careful.

Wright Field was the centre for testing a new generation of super-fast aircraft. Yeager was upgraded to test pilot just as the Air Force took receipt of a unique research aircraft, the Bell X-S1. The X stood for experimental and the S for supersonic. It cost $6 million to develop and it was top secret. The orange fuselage was shaped like a bullet and was propelled by four rockets called ‘Black Betsy’. It was built for one purpose: to smash through the sound barrier. It would not be easy and would definitely be dangerous. Strange things happened to planes that dared to approach the speed of sound, Mach 1* (1,216 kilometres per hour at sea level).

In 1943 Miles Aircraft in England was at the forefront of aeronautical innovation. One of the Miles brothers was the father of Mary Miles, who married the ill-fated Peter Small. The brothers produced the M.52, an experimental plane with ‘special edition’ Whittle engines that were far more powerful than other jet engines of the time. It was expected to reach 2,600 kilometres per hour. Its sharp-edged wings, designed to slice through the turbulence when close to Mach 1, earned it the nickname the ‘Gillette Falcon’. Engineers from the Bell Aircraft Company came to England to consult with the Miles brothers. Perhaps as a consequence, the Bell X-S1 developed ultra-sharp leading edges on its wings like those of the M.52. Unfortunately, the M.52 never got a shot at the sound barrier; the British government cancelled the contract.

De Havilland, another British Company, built a revolutionary swept-wing, tail-less research plane powered by four gas turbines. Wind-tunnel tests of the D.H. 108 revealed some instability, as with other tailless aircraft, but in more than a hundred test flights she performed well and reached 0.89 Mach in level flight. The owner’s son Geoffrey de Havilland was piloting the D.H.108 when, in a fast dive, it became violently unstable and disintegrated. Geoffrey died of a broken neck before he hit the ground. His brother had already been killed in a mid-air collision.

Chuck Yeager knew from experience that as an aircraft approached Mach 1 it began to shake and the controls could ‘freeze’. Perhaps the sound barrier was more than just a name. Some aeronautical engineers believed that as the pressure built up in front of a speeding aircraft the shock wave at Mach 1 might be like hitting a wall, which neither pilot nor plane would survive.

The top brass at Wright Field asked for volunteers to pilot the X-1 (the ‘S’ had been dropped to hide the fact that it was attempting to go supersonic). Both Yeager and Bob Hoover stepped forward. They were not short on courage. During their training as fighter pilots their squadron lost thirteen pilots in six months. They had survived, and daily dogfights with enemy planes made them fatalistic. But they never used the word ‘crash’. Instead, anyone who ploughed into the ground was said to have ‘bought the farm’. The RAF too said ‘he bought it’ or, more enticingly, ‘he went for a Burton’. Yeager figured that they were accustomed to sorties on which they never knew what might happen next. Experimental flights were no different.

To the astonishment of all the higher-ranking test pilots, Yeager, a mere captain, was chosen to be the principal test pilot for the X-1 flights, with Bob Hoover as his understudy. The other pilots scoffed that the powers above had selected the two most expendable pilots. No one believed they had a hope in hell.

In fact, Yeager was chosen because his commanding officer believed that if it could be done Yeager was the man to do it. He had a instinctive ‘feel’ for every aircraft he flew. It was as if he became one with the machine.

The worst chore was training. Yeager hated the giant centrifuge in which they frequently – and literally – went for a spin. It exposed them to forces many times greater than the Earth’s gravitational pull and took them way beyond nausea. Even the bravest pilots broke out in a cold sweat when strapped in the centrifuge for another stint of life without blood in their head. There were also endless sessions in a cold low-pressure chamber in conditions similar to those to be found at 21,000 metres. They tested pressurised suits and on one occasion Hoover had difficulty breathing and his face turned purple. They had forgotten to attach his oxygen supply.

A corset maker constructed the flight suits. When flying back from a fitting at the factory Chuck and Bob’s plane was struck by lightning and almost went down. To be killed on a routine flight while waiting to pilot the most frightening brute ever invented would have been the ultimate irony.

Chuck chose Jack Ripley as his flight engineer for the experimental flights. Ripley had to be kept away from the explosive fuels as he was a chain-smoker and his shirts were full of burn holes from fallen cigarette ash. He was well weathered. Although only in his late twenties, Chuck’s wife thought Ripley could pass for a hundred and three.

Chuck knew that Ripley was not just hot on the theory of aeronautics, he was an immensely practical man. When a pilot made an emergency landing on a small airstrip Yeager and Ripley went to retrieve the plane. It was stranded because, loaded with fuel, it would need a much longer runway to take off. Ripley calculated the minimum amount of fuel it would need to get back to base. He then paced out the runway and hammered in a stake to mark the spot where Yeager should fire the jet booster on take-off. Ripley assured him that he had three metres to spare. Yeager plunged down the runway and lifted off – with three metres to spare.

At last Yeager got to meet the X-l. Even in its hangar it was chained down like a wild beast that had to be restrained. On his first flight the X-l would carry no fuel. He would practise gliding down and landing. Even when powered, the X-l would have to glide home because all of its several tonnes of fuel would be burnt within 4.2 seconds.

The X-l didn’t take off. It was carried aloft slung beneath a modified B-29 bomber. At the designated altitude Yeager had to climb down a ladder in the bitingly cold wind and slide into the cockpit. He put on his helmet. As they hadn’t supplied him with one, he had cut down the leather helmet usually worn by a tank commander.

Yeager heard the pop of the release and dropped rapidly out of the bomber’s shadow into dazzling sunlight. He was on his own. The X-l handled like a dream and he enjoyed the silent slide towards the ground.

In August 1947 he made his first X-l powered flight. The rockets ran on alcohol and liquid oxygen. They were meant to be explosive. When the X-l carried fuel for a test flight the entire base was shut down. If there was an explosion Yeager would have a ringside seat. The cockpit was filled with non-flammable nitrogen so he was reliant on an independent oxygen supply. With tanks of liquid oxygen at -182° C right behind him Yeager felt chilled. Apprehension also contributed. If the aircraft had faults they would reveal themselves here, when he and the X-l were alone together, 12,000 metres above the ground.

There was no bail-out option. The door was at the side of the cockpit and if he managed to jump he would be instantly bisected by the razor-edged wing. Nonetheless, they gave him a parachute. It made a good cushion. The only outcomes were that he would become a hero or a dead hero. He couldn’t lose. So he fired the first rocket.

Flames leapt six metres behind the plane and Yeager felt as if a truck had just rammed him from behind. He was travelling. At 300 metres below the mother ship he ignited a second rocket and was thrust up to 0.7 Mach – and this was on half-power. He made a barrel roll in celebration and the engines cut out. He would get a rollicking when he landed. He had strict instructions not to fire the remaining two rockets so he ditched the remaining fuel before gliding home.

On his sixth test flight he hit 0.86 Mach and the aircraft began to shudder as if it were running on a cobbled street. The controls became sluggish. The seventh flight was worse. At 0.94 Mach the hand controls failed to respond. If, as predicted, the nose pitched on breaking the sound barrier, and he couldn’t correct it, it would be curtains. The project was about to be abandoned when Ripley had an idea. He fitted a motor that would alter the configuration of the tailplane independent of the hand controls. Many years later an airliner lost control and the pilot used the wing engines to lift the nose and the third engine on the tail to move the nose down. His ingenuity saved the lives of over two hundred passengers. Ripley was trying a different way to do something similar. But would it work at the speed of sound?

It worked on the next flight at 0.988 Mach, but the windscreen frosted over. Yeager was blind and with no navigation instruments to get him home. Hoover in the chase plane talked him down and he made his most gentle landing. Wiping the windscreen with hair shampoo solved the frosting problem.

While preparing for his attempt to break the sound barrier, Yeager fell off a horse and broke a couple of ribs. He was in pain, but with tight bandaging and painkillers he thought he would be able to fly. The main problem was that he couldn’t lean over to lock the cockpit door. Ripley sawed off a piece of broom handle that allowed him secure the door.

On 14 October 1947 Yeager’s ribs had a bumpy rocket ride. When he fired the final rocket he noticed that the needle on the speed gauge had gone off the scale. At that moment he vanished from sight and there was a loud explosion. Observers thought that Yeager was lost, but it was the first-ever sonic boom. He was travelling at Mach 1.07.

There was no announcement from the Department of Defense. They wanted to keep it secret until they developed a supersonic fighter. Yeager continued as a test pilot and his very next flight in the X-l was the scariest. When he clicked the switch to fire the rockets, nothing happened. All he could do was to ditch the fuel and glide down, but without power he couldn’t open the valves to expel fuel. He remembered there was a manual control for venting and used it. Without a working gauge he had no idea how fast it was bleeding out or how much fuel was left in the tanks. The flimsy landing gear of the X-l was designed to take the weight of the aircraft. It would collapse under the extra burden of any significant amount of fuel left in the tanks and an explosion would be inevitable. Yeager delayed landing for as long as possible and made the most nervous touchdown of his life. His luck held.

What was Yeager’s reward for his skill and daring? Civilian test pilots got substantial danger money, even when working for the military. Yeager got a bar on his Distinguished Flying Cross and later an array of awards including a peacetime Congressional Medal of Honor. But he was banned from making any money from publicising his exploits and was not promoted from captain to major until seven years later.

It had been clear for a while that the increasing speed of fighter aircraft made it difficult for the pilot to escape from a disabled airplane. Clambering out of the cockpit was impossible when the plane was travelling at 800 kilometres an hour or more. He had to be forcibly ejected. Experiments with dummies indicated that the pilot might survive. Miles Aircraft patented an ejector seat as early as 1939, and the Martin Baker company tested a modern ejector seat in 1945.

The principle was that an explosive charge would simultaneously remove the cockpit’s canopy and blast the pilot and his seat clear of the plane. In the Martin Baker factory there was a test rig that thrust dummies aloft up a steep chute. Bernard Lynch, a fitter from the shop floor, volunteered to be the first person to ride the rig.

The tests showed that a force of 25 G (twenty-five times the gravitational pull of the Earth) applied ‘gradually’ over a tenth of a second would hoist the pilot up at a velocity of eighteen metres per second to clear an aircraft flying at 800 kilometres per hour. And it did this without concertinaing his spine. The ejector seat was installed in a Meteor III jet fighter and test pilot Bryan Greensted survived ejection.

To protect the pilot, the explosive charge was activated by pulling a heavy canvas sheet over his head. When it reached his waist the seat blasted off. The force of his ejection ensured that his hands pulled the hood tightly over his head, preventing any violent flexing of the neck.

The pilot’s problems were not over when he departed the aircraft. Four years before Yeager arrived at Wright Field another self-experimenter was putting himself at risk. Lieutenant Colonel William Lovelace was director of the Aero-Medical Laboratory. He considered the parachutist’s plight. Within a minute of bailing out at altitude, a pilot went unconscious and couldn’t pull the ripcord to release his parachute. Lovelace developed an oxygen breather to keep him alive until he dropped low enough to breathe the air.

To prove it worked in practice he bailed out of a B-17 bomber at an altitude of 12,200 metres. It was the first time he had jumped out of a plane. He plummeted in free fall and then released his parachute. He had assumed that the jolt of it opening would be about 4 G, but at this altitude the jolt delivered an almost instant deceleration of 33 G. His body suddenly became thirty-two times heavier. It knocked him unconscious. It also tore away his glove at an altitude where eyelids freeze shut. Lovelace got frostbite in his hand. Having survived such an enormous G-force he ricked his back on landing where forces involved were a paltry 3 to 4 G. Like Yeager, he was awarded the DFC for his pains.

To avoid an excessive jolt pilots free-fall until they reach terminal velocity (thirty-three metres per second) before opening their chute. Thanks to Lovelace’s experience parachutes that opened automatically were developed.

Rapid deceleration is what does the damage to the occupants when an aircraft or vehicle crashes. Also, when a pilot ejects, he suffers abrupt linear deceleration the instant be emerges from the speeding plane. Colonel John Stapp, a flight surgeon, decided to explore the limits of human tolerance of deceleration. He was the ideal person. In addition to his medical degree he had a PhD in biophysics. He gathered data on types of restraining harness and attended postmortems to see how the harnesses performed in accidents. Perhaps he could improve their design.

To decelerate Stapp first had to accelerate. What better than a rocket-propelled sled? A heavy-duty railway track was laid near the Holloman Air Force Base in New Mexico. It was over 1,000 metres long. The sled would not run on the tracks; they would merely keep it on a straight line. The sled Sonic Wind was manufactured by the Northrop Aircraft Company. It had nine rockets that delivered 20,430 kilograms of thrust in just 0.07 seconds. There were no conventional brakes: a bucket scoop underneath the sled dug into a trough of water between the tracks. It was the equivalent of hitting a brick wall.

Thirty preliminary runs with a dummy in the sled gathered useful data. Stapp had calculated the forces involved. Now he had to find out what they felt like. He had been ordered to supervise the project and decided that he should be the main gúinea pig: ‘I felt fortunate that my goal was to save lives, not to shoot.’ He later allowed others to volunteer but made sure they were aware they were going to get hurt. His volunteers included pilots, flight surgeons, a medical technician and two harness makers.

Stapp adopted a rigorous regime prior to a test run. He shunned alcohol and fasted. An empty stomach and bladder were less likely to rupture in an accident and a full stomach makes for a messy post-mortem.

Stapp rode the sled twenty-two times. Each run was faster than the previous one. He tried to keep his hands well inside the fairing. Twice before, a straying hand had caught the wind and his wrist had fractured instantly. He concentrated on keeping alert so that he would remember the details of the experience for his report. His aim was to determine the ‘point of beginning injury’. He could only do so by going beyond that point.

His twenty-second run on 12 December 1954 would be his fastest. Before the rockets were ignited Stapp’s heart rate soared and his spirits sank. His protective gear was just a harness, a helmet and a rubber bite to prevent him from guillotining his tongue with his teeth. The rockets fired and within five seconds he was travelling at over 1,000 km per hour (632 mph). He could overtake a .45 calibre bullet. There was no windscreen so he was buffeted by the wind. Sand bit through his flight suit to pincushion his skin. His eyes were being compressed into his skull. He withstood a force of 40 G for twenty seconds – a very long time to endure such stress. As the blood supply to his eyes was disrupted his vision dimmed and he went through a blackout (everything black with eyes wide open), followed by a red-out. The scoop hit the water and the sled stopped in one and a half seconds. Stapp’s eyes ballooned out of their sockets. Had his retina detached he would have been blinded. While recovering in hospital he experienced ‘survival euphoria’.

When Stapp began his experiments experts believed that a human could not withstand more than 9 G. To go beyond that was courageous. To go so far beyond was extraordinary. In 1958 one of Stapp’s colleagues survived a sled run that subjected him to 82.6 G. His name was Eli Beeding, a name too close to ‘He lies bleeding’ for comfort. He survived because he was wearing Stapp’s improved harness and sitting up so the forces hit him in the back and chest. Had he been lying down it would have been a different matter. The US Air Force came up with the idea that it might be safer if ejector seats propelled the pilot forward rather than upwards, just as a high diver enters the water head first. Stapp decided this was too dangerous for a man to try so a heavily anaesthetised monkey rode the sled lying down. It did not survive. In that position the blood was rammed up into the skull, bursting blood vessels and destroying tissue.

The worst that Stapp suffered was extensive bruising and concussion, and an abdominal hernia, as well as fractured ribs, wrists and coccyx. He also developed chronic vertigo if he shut his eyes and tried to balance. He refused any compensation for his injuries because they were merely routine hazards for which he received standard flight pay. He said, ‘I saw no difference between doing a human experiment and leading a charge to take an objective … in a military context I was expendable.’

The speed of progress in aviation was astonishingly fast. The first flight of the Wright brothers’ biplane on December 17th 1903 lasted twelve seconds and a jogger on the beach at Kitty Hawk would have overtaken it. It reached an altitude of two metres. Only sixty years later Concorde made its maiden flight and was soon taking paying passengers across the Atlantic faster than the speed of sound. These advances would not have been possible but for the experiments of many brave men.

Stapp became chief of the Air Medical Laboratory, and was later placed on permanent loan to the Department of Transport for research into car restraints. In the same year that he had survived an abrupt stop from 1,000 kilometres per hour almost 40,000 American motorists had died from crashes at forty kilometres an hour or slower.

Stapp became an important advocate for increased car safety and devoted himself to making car crashes more survivable. This required more human deceleration experiments for him and others. In polite conversation the term ‘biomechanics’ was used to refer to the violent business of determining how much impact people could stand. Stapp boasted that between 1947 and 1970 he and his volunteers had endured over five thousand voluntary human experiments without a single disabling injury or loss of life.

The Society of Automotive Engineers established a foundation in his name for training engineers in safety matters, and the Stapp Car Crash Conferences are held regularly all round the world to report the latest developments in car safety.

The US car industry resisted all change. Their priority was styling, not safety. The president of General Motors boasted that his company was run by salesmen, not engineers. When seat belts were first introduced into production cars there were those that claimed they would damage drivers more than the collision. But they hadn’t ridden the Sonic Wind. Thanks to John Stapp and his experiments many hundreds of thousands of people are alive after surviving potentially fatal car accidents.

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Piccard’s giant balloon. The tiny sphere at the bottom housed the crew.

* Because the speed at which sound travels varies with altitude, air speed is often measured in relation to the speed of sound (Mach 1) at the height the plane is flying. This scheme was devised by Ernst Mach, an Austrian physicist.