In 1962 the United States Air Force was working
furiously to develop an ejection system for pilots of the new Convair B-58 Hustler. The first jet bomber capable of mach 2 flight. Bailing out at the speeds and altitudes the
B-58 was designed for with conventional ejection seats of that era would have resulted, at
best, n severe injury. Windblast would have likely rip your helmet
and air supply off, the force of air would violently contort your limbs, with the explosive
thrust of the ejection seat compressing your spine, and if all that didn’t kill you. You may just freeze to death, with eternal
temperatures dipping to as low as -50 degrees celsius. And so the Stanley Aviation Company and Convair
began a partnership to develop a fully enclosed escape capsule, which would fold shut before
ejection and shelter the crewmen from the environment, but they couldn’t start testing
this new concept on humans. The conditions were simply too hostile to
risk a human on, so they came to the next logical alternative. The United States Air Force strapped a drug
up Black Bear called Yogi into the capsule and launched it at 35,000 feet at supersonic
speeds. [1] So how the hell did the world of aviation
come to the point of needing to fire live black bears at supersonic speeds? Ejection seats were not always necessary in
flight. At the relatively slow speeds of WW1 and early
WW2 era planes pilots could simply unstrap their restraints and jump overboard, like
this German pilot being pursued by an RAF Tempest. But as the war progressed and jet propulsion
technology advanced, British Intelligence began to receiving reports of German pilots
being “fired into the sky” from defeated German jets. As usual, the Germans were well head of the
competition in experimenting with new technology, and the medical branch of the Luftwaffe was
busy testing the physical limits of the human body to withstand G forces. The designers of these devices had a difficult
balancing act to co-ordinate. It was essential that the ejection provided
enough acceleration for the pilot to safely clear the aircraft, while not accelerating
them so fast that they could suffer injury. The first thing these designers needed to
consider was how to power a device like this. They needed a way of storing potential energy
that could be released rapidly in order to achieve the necessary acceleration in an emergency
situation. Early designs simple called the pilot to manually
release the canopy before triggering a compressed spring that would hopefully launch the pilot
clear of the plane like some sort of Wile Coyote scene. This had some obvious inherent flaws. The springs did not possess the necessary
potential energy to launch the weight of the pilot and seat upwards to safety, and requiring
the pilot to manually release the canopy in an emergency situation was incredibly dangerous. As Douglas Davie discovered to his demise
in 1944, during a test flight of the the British prototype twin-engined jet fighter, the Meteor. While performing a high speed test the aircraft
lost one of it’s engines sending it into an uncontrollable spin due to differential
thrust. At this time Britain had not put serious consideration
into escape mechanisms, and Davie was forced to open the canopy manually, which snapped
shut and severed his arm. He was then either then thrown out of the
plane by the g-forces of the hurtling aircraft, or somehow managed to haul himself out. Only to be critically injured by the aircraft’s
tailplane. [2] This gruesome event highlighted to the British
the need to develop ejection mechanisms, and with the end of the war coming, they would
have plenty of German engineering to gain inspiration from. The Germans were racing ahead of the competition,
thanks to the huge amount of resources the Germans poured into experimental aircraft. By definition, these aircraft were unpredictable,
and so the Germans also lead the way in developing escape mechanisms. Helping save talented test pilots like Helmut
Schenk, who was the first man in history to use an ejection seat in an emergency situation,
while testing the Heinkel He-280 jet fighter. This seat did not use springs to power the
ejection, but compressed air. An important improvement in energy storage,
but required a significant amount of additional mechanisms and heavy parts to operate, like
valves and pressurised air tanks. Despite the relatively cumbersome design of
these ejections seats, by the end of the war it is reported that up to 60 luftwaffe airmen
had used these devices to escape their aircraft, and every experimental aircraft the Germans
tested came equipped with an ejection seat. After the war the Allies took over as the
forerunners of ejection seat design. Most notably by an Irish engineer, James Martin. Who founded the Martin-Baker company alongside
Captain Valentine Baker. They conducted their own tests of human endurance
using this tripod launcher. Another Irish man, Bernard Lynch, being the
brave human guinea pig. They used an explosive cartridge to power
the launch, instead of compressed air, and gradually upped the explosive power. With explosive upward trajectories like, injury
becomes much more likely if the pilot does not remain upright in his seat, a difficult
task when under such immense g-forces. And so Martin Baker cleverly built the trigger
into a retractable head cover which restrained the pilots head in an upright position, and
protected it from windblast. While revolutionary in it’s design this
ejection seat was incredibly simple compared to modern ejection seats. Every step of the process was manually except
for the deployment of the drogue shoot, which was triggered when a fifteen foot wire attached
to the firing mechanism and the cockpit floor reached the end of it’s line on ejection. The pilot needed to jettison the canopy manually,
pull the face curtain trigger, wait as the drogue shoot decelerated and stabilised his
fall, then unbuckle his belts and jump clear of the seat to deploy his own parachute. An impossible task if the pilot was knocked
unconscious during the ejection sequence. Martin-Baker won a contract with the RAF for
all future aircraft to be fitted with this first generation seat, and it saved it’s
first life in 1949 when Jo Lancaster was testing the Armstrong Whitsworth A.W.52, an experimental
flying wing aircraft, which entered an uncontrollable pitch oscillation due to aerodynamic flutter
of it’s elevons. Lancaster escaped and survived to tell the
story, but there was plenty of work left to do. Lancaster was lucky, as the problem was encountered
at relatively high altitude. Leaving him plenty of time to deploy his parachute,
but most problems occur during take off and landing, and so the next vital step in ejection
seat design was developing a zero-zero ejection seat. A seat capable of saving the pilots life at
zero velocity, and zero altitude. Here we are beginning to strike the limit
of human endurance. To safely evacuate an aircraft at an altitude
this low would require significant sustained acceleration to ensure clearance of a crash
and an explosion, and provide enough height to safely deploy a parachute. With tolerances this tight we first need to
automate more steps. By the 1960s both Martin-Baker, and their
American counterpart Weber were developing these zero-zero seats. [5] By this time Webers seats had saved over
500 lives, and had been fitted in aircraft like the f-106 and the gemini space capsule. The F-106 served in the US Air Force for over
40 years and during that time was fitted with three different ejection seats. The interim seat, the Supersonic Rotational
B-seat, and finally the zero-zero Rocat. [7] Each showing the gradual change in design
ethos to what would eventually become the modern day standard design template. The interim seat was highly automated, with
a carefully choreographed ballet of mechanical triggers like an advanced rube goldberg machine, all
starting with the pilot pulling these ejection handles. Triggering an explosive initiator [5] to fire
which would began a chain reaction of events through the hot gas emanating its fix volume
chamber. This hot gas would flow through ballistic
hoses to other firing pins in propellant powered actuators, the pressure of the gas would remove
the firing pins. Allowing the actuators to fire and unlatch
the canopy, and forcefully remove it from the aircraft. As the canopy cleared the aircraft it would
pull a lanyard, which would trigger the explosive cartridge that would lift the seat clear of
the plane. As the seat travelled up the rails it would
impact another trigger firing a final time delayed initiator, which would activate the
drogue shoot and release the seat buckles. The pilot would then either freefall, or,
if they had attached their zero delay lanyard, would have their parachute deployed automatically
as they fell free of the seat. This carefully timed sequence was a massive
improvement to manual steps of old, but it was missing two vital things. It was not capable of supersonic ejections
or zero-zero ejections. Initially pilots pushed for supersonic capabilities,
and so one of the most intricate and fascinating ejection seats in history, the B-seat, was
developed. This seat was designed to raise and rotate
into the airstream, where the bottom of the seat would protect the crew from airblast
and act as an aerodynamic surface to provide lift, raising the seat away from the aircraft. At this speed the seats need extra lift to
ensure they will clear the plane on time, and to help with that goal rocket motors would
fire to lift the seat to safety. The seat had two telescoping booms that helped
stop the seat from rolling violently on ejection. This was an ingenious design, but absurdly
complicated with over 30 pyrotechnic devices from initiators, explosive bolts and wire
cutters. This complexity led to a number of fatal ejections,
and with mounting statistical evidence that supersonic ejections were much less likely
than a slow and low ejection, a replacement was requested. And thus the zero-zero seat was developed,
using the interim seat as a base. Adding rocket motors to provide the necessary
height to clear the plane after the initial ejection, and adding an explosively deployed
parachute to ensure it opened quickly. Unlike the escape capsule of the B-58 this
system was not tested with a bear. It was tested by a lunatic by the name of
Jim Hall. Jim Hall is quoted saying “I have been kicked
in the ass harder than that”. This may well have been the source of the
liar liar pants on fire phrase. This zero-zero design has been the template
for all ejection seats since, with Martin-Baker becoming the world leading manufacturer adding
incremental improvements over the past 60 years. Adding sensors and flight computers, along
with vectoring nozzles for the rockets to ensure the optimum trajectory of the seat,
even with the plane rolled upside down. Incremental improvement like this over the
years leads to a vastly better product, and you can make your own incremental improvements
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