Ejection Seat Timeline
1941
Swedish designer patents compressed air system
1943
Jan - First emergency ejection
Saab Mk1 catapult seat tested
1946
March - First ejection from an American designed seat at 7800 feet and 308 mph.
1949
May - First US test ejection from a jet aircraft at 10,000 feet and 430 mph.
August - First US pilot to use a seat in an operational aircraft.
1961
First test of Martin-Baker zero-zero seat
1983
Martin-Baker reaches 5000 successful ejections
1990
December - Martin Baker has its 6000th successful ejection
1993
September - McDonnell Douglas ACES II has its 300th successful ejection
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Generations of Seat Designs
First Generation - (1940-1965) These seats were purely ballistic operation with a compressed air, mortar, or rocket cartridge providing a single force to remove the seat and occupant from the aircraft. In early generation 1 seats, the occupant had to deploy the parachute manually. In later seats this became an automatic function. Examples of first Generation seats would be the Saab Mk 1 and the Martin Baker Mk 1-5 seats.
Second Generation - (1965-1975) Accumulated information had shown that a catapult alone would put too much force/acceleration on the occupant to survive an ejection without significant injury. Also, the end users of the seats were looking for zero/zero performance and performance at high speed. To accomplish this, a rocket sustainer was added. The catapult would operate from 0.15 to 0.25 seconds to keep the initial acceleration under 10G. The rocket sustainer would then act for an additional 0.20 to 0.40 seconds. The Martin Baker Mk 7 and the Douglas Escapac seats would be examples of this generation.
Third Generation - (1975-present) Automated features had been added to seats such as drogue chutes, parachute deployment based on altitude, and automatic deployment of survival gear since the first generation. But the advances in electronics allowed a computer to be placed into the seat and control the functions based on readings from sensors. Pitot - static systems, gyroscopic stabilizers, and pilot weight indicators were added to give information to the seat computer, extending the ejection envelope and improving crew survivability. Representative examples of the third generation are the Martin Baker Mk 14, The McDonnell Douglas ACES II, and the Stencil S4S.
Fourth Generation - (present) Research continues on expanding the envelope for the systems. Martin - Baker Aircraft, Boeing (McDonnell Douglas), and the former Soviet Union have either tested or placed into service seats featuring vectored thrust, flow generators, or variable thrust rockets.