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From: Miloch <Miloch_member@newsguy.com>
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Subject: Martin-Baker Mk.1 Ejection Seat
Date: 11 Jul 2018 10:15:31 -0700
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https://en.wikipedia.org/wiki/Martin-Baker_Mk.1
The Martin-Baker Mk.1 is a British ejection seat designed and built by
Martin-Baker. Developed in the late 1940s it was the first in the line of
production Martin-Baker seats for military aircraft. Ground and air testing of
earlier designs resulted in the first successful test ejection of a company
employee in July 1946. A seat type designed for the Saunders-Roe company was
known as the Pre-Mk.1.
The death of Valentine Baker in an aircraft accident in 1942 prompted James
Martin to investigate new methods for aircrew escape and survival. Martin had
previous experience of aircraft survival systems and had designed a
quick-release canopy system during the Battle of Britain, a very successful
device that was later fitted as standard to all Spitfires during manufacture.
In 1944 Martin was approached by the Air Staff after a fatal accident with the
jet-powered Gloster F.9/40 (Gloster Meteor prototype). They asked for an escape
system that forcibly ejected the pilot from an aircraft and was powerful enough
to clear the tail surfaces at high airspeeds. German and Swedish engineers were
investigating the same problem, but Martin was unaware of this.
Martin initially investigated systems that could be retro-fitted to existing
fighter aircraft types that were in service at the time. His first design, a
spring-powered swinging arm, hinged near the base of the fin, was not pursued
although a Boulton Paul Defiant aircraft had been loaned to the Martin-Baker
company for modification and testing.
A method using explosive charges to clear the seat from an aircraft was
investigated next, as no information was available on what effect the g-forces
might have on the human body a 16 feet (4.9 m) test rig was constructed at
Denham for readings to be taken. On 20 January 1945 a 200 pounds (91 kg) dummy
was test fired on the rig, four days later a company fitter, Bernard Lynch
volunteered to test the system and was fired to a height of just under 5 feet
(1.5 m) with no ill effects felt. The size of the explosive charge was
progressively increased until Lynch reached a height of 10 ft and declared that
he was experiencing pain. News of the test quickly reached the aviation press, a
journalist from The Aeroplane was hospitalised with crushed vertebrae after
trying out the rig for himself.
On 12 September 1945 the Martin-Baker company was awarded a contract to design
and produce two seats for high-speed testing, a Gloster Meteor aircraft was
modified for testing. The first airborne test with this aircraft took place over
Chalgrove airfield in June 1946. Using a dummy the parachute failed when it
opened prematurely at a speed of 415 miles per hour (668 km/h). A time-delay
release mechanism was developed and initially suffered from problems. After many
more tests it was felt that the system was safe enough for a manned live test.
The volunteer was again Bernard Lynch, firing himself from the rear cockpit of
the Meteor at 8,000 feet (2,400 m) over Chalgrove on 24 July 1946, the system
worked perfectly.
Many more tests followed at ever increasing altitudes and airspeeds, some live
and some with dummies. By 1948 the design had been refined enough to enter
production for use in Royal Air Force and Fleet Air Arm aircraft. Prior to this
order the Saunders-Roe company requested a seat to be used in its SR.A/1
jet-powered flying boat. This seat was known as the 'Pre-Mk.1' and did not
feature all the refinements built into the production Mk.1 seats.
The first prototype Armstrong Whitworth A.W.52, TS363, crashed on 30 May 1949,
the pilot, J.O. Lancaster, used the pre-Mk.1 ejection seat to save his life,
making it the first occasion of an emergency ejection by a British pilot.
Operating the face blind firing handle initiated firing of the main gun located
at the rear of the seat, the main gun being a telescopic tube with two explosive
charges that fired in sequence. As the seat moved up its guide rails an
emergency oxygen supply was activated.
As the seat moved further up and out of the aircraft a lanyard attached to the
cockpit floor fired a steel rod, known as the drogue gun, this extracted two
small parachutes to stabilise the seat's descent path. The occupant then
released themselves from the seat harness and operated the main parachute
manually by pulling a ripcord.
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