Douglas A/B-26 Invader
Ejection seat test bed aircraft
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Douglas A/B-26 Invader Ejection seat test bed aircraft |
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The name Martin-Baker is synonymous around
the world with the design and construction of emergency ejection seats. Through half a century of development, today's fully
automatic zero-zero rocket assisted ejection seats are a far cry from the basic seat in which Bernard Lynch made the company's
first live airborne ejection in July 1946. Amazingly this first ejection was made from the same type of aircraft that Martin-Baker
uses as its ejection seat testbed today - the Gloster Meteor. The work completed by the Martin-Baker Meteors since, and the
tremendously brave volunteers who conducted the early live test ejections, have saved many thousands of airmen's lives. Escape from a damaged or uncontrollable
aircraft had naturally been at the forefront of pilot's thoughts right from the earliest days of flight. The terrible losses
suffered by aircrew on both sides in World War I forcefully highlighted that in future conflicts, an air force's greatest
asset - its highly-trained pilots and aircrew - must be offered an effective way of emergency escape, and the most obvious
solution was the parachute. During World War I escape by means of parachute had become a regular occurrence from observation
balloons and airships. However, pilots of fixed-wing aircraft were generally not afforded such a luxury and were obliged to
either attempt to bring their damaged aircraft to earth in a forced-landing or, if the airframe had ignited, jump from their
aircraft to face almost certain death to prevent being burned alive. In the inter-war period the parachute was steadily introduced
into widespread use for combat aircrew around the world. Using the standard practice of standing up in the cockpit and diving
over the side of the aircraft - aiming to miss the trailing-edge of the wing - parachute escape saved many hundreds of lives.
As is the case in times of conflict, technological advances allowed the performance of combat aircraft to advance at a startling
rate during World War II. In the mid-1930s, the RAF was equipped with biplane fighters such as the Gloster Gladiator, with
a maximum speed barely exceeding 250mph. A decade later the RAF was busy equipping
with its first generation of jet fighters capable of speeds in excess of 5OOmph. Experience in air combat had revealed that
the 'over-the-side' technique of exiting an aircraft was becoming increasingly difficult and, in a growing number of cases,
was proving impossible. Attempting to stand up and dive from a cockpit in a slipstream of over 400mph, with the pilot often
under a significant g-loading, was beyond the capabilities of any pilot. A number of promising schemes were devised
during the war to aid emergency exit. In Germany, the deficit of experienced fighter pilots prompted Hans Sander, Focke-Wulf's
chief test pilot, to form a small design team to devise an emergency escape system for the company's Fw190 fighter. A forerunner
of the successful ejection seats introduced post-war, the system showed great promise, but the timescale and resources needed
to introduce the device could not be allocated as Germany's position became increasingly desperate. Meanwhile, in the UK, the need for such
a system was finally rammed home with the death of one of the Royal Aircraft Establishment's (RAE) leading test pilots, Squadron
Leader Davie, and the loss of a valuable prototype of what was to become the Gloster Meteor. During a test in January 1944,
an emergency was encountered and the pilot attempted the standard abandoning technique. However, the high airspeed caused
injury as he leapt over the side of the stricken aircraft, causing him to lose consciousness and therefore make no attempt
to open his parachute. The Air Ministry, after a thorough investigation,
concluded that the increasing performance of aircraft, accelerated by the introduction of jet engines, would render conventional
emergency escape techniques obsolete, and a new system would have to be devised. The most attractive of these would be by
forced ejection of both seat and occupant by explosive charge and, in a far-sighted move, the Ministry of Aircraft Production
invited a little known aircraft designer - James Martin - to investigate the practicability of providing fighter aircraft
with a means of assisted escape for the pilot. At that time there had been little research into the effects on the human body
of a sudden and powerful vertical compressive thrust. To conduct the necessary physiological research, the company devised
and built a 16ft vertical test rig in tripod form, with one of the legs encompassing guide rails along which a dummy pilot's
seat would travel. The seat was activated by two telescopic tubes driven by an explosive charge. After tests with a dummy,
the first live test was made by Bernard Lynch on 24 January 1945, to a height of 4ft Sin. The power of the cartridge was increased
steadily until 10ft was reached. However, as the firing mechanism became more powerful, the stress on the human body was reaching
intolerable levels. This manifested itself the injury of a technical journalist who was admitted to hospital with crushed
spinal vertebrae. To help overcome the problems associated with spinal compression, James Martin acquired a human spine, and
tests on this, along with the test rig research, allowed Martin to calculate the design criteria which his new design (and
all subsequent ejection seat designs) must follow: 1. The peak acceleration should not exceed
21 'g' and this peak should not be held for longer than 1/1O th of a second. 2. That the rate of rise of 'g' should not
be greater than 300 'g' per second. 3. That in sustaining this acceleration,
the body should be held in a position to ensure that adjacent spinal vertebrae are square to each other. To aid the design of the seat and firing
mechanism a new 65ft test rig was built. The seat now incorporated a firing handle above the occupant's head to ensure the
spine was in the correct alignment and a rearrangement of the footrests. Meanwhile, the company had been allocated a Boulton
Paul Defiant for modification, for the commencement of airborne tests. At this time the company was using Oakley Airfield
near Thame, Oxfordshire, for its test flying. It was here that the modified Defiant, incorporating structural changes to the
rear cockpit (which included the removal of the turret and the fitting of the experimental ejection seat) began its test programme.
After successful static test of the seat, loaded with sand bags, on 10 May 1945, the first ejection from an aircraft in flight
was made the following day with Brian Greenstead piloting the aircraft. Six further dummy elections were made from the
Defiant at speeds up to 300mph. However, with the initial live test programme on the 65ft rig reaching its conclusion and
the concept proved, it was time to look for a new flying testbed that would have more representative performance of the latest
RAF combat aircraft. On 6 November 1945, a modified Meteor F3
(EE416) arrived at Oakley to begin the company's 57 year association with the aircraft Design work had begun on the aircraft
the previous September after the Ministry of Aircraft Production decided that it was the type most suited to the task. Fitted
with Rolls-Royce Derwent I engines, the forward fuselage section was considerably modified to allow the ejection seat and
its associated apparatus to be fitted behind the pilot's cockpit, in what was formerly the ammunition bay. The original seat
bulkhead was removed and replaced by a newsloping bulkhead further aft, the rear decking was modified and the floor beams
reinforced to withstand the stresses imposed by the ejection gun. On completion of the modifications the aircraft was delivered
to Chalgrove airfield, Oxfordshire, which has remained Martin-Baker's main test flying base to this day. After a static ejection, with the aid of
a catch net, was made on 8 June 1946, the first airborne dummy ejection was completed on 24 June at a height of 2,000ft and
an indicated speed of 415mph. The initial dummy tests were not a success, as the speed of the airflow caused the parachute
to burst with the loss of the seat. To cure the problem, a drogue parachute was incorporated to help slow the seat before
the deployment of the main parachute and, after several failures at perfecting the new system, the prototype seat was declared
ready for live testing in late July.
The US Navy arranged with
Martin-Baker to provide a seat somewhat tailored to US Navy requirements as well as technical support from that company to
develop it. Photographs of this first M-B provided US Navy seat show it to be quite similar to that company's 'pre-Mk.I' seat.
Along with the actual seat, a 105 foot tall test firing tower was also acquired and a converted Martin B-26 Invader (US Navy
JD-1) was specially fitted for planned aerial test firings. Having proved the concept, Martin-Baker progressed to design its first production seat, the Mk 1, which incorporated a host of improvements identified by the engineers, Lynch and James Martin. The new seat was guided during ejection by four rollers on the seat structure running in a guide rail assembly bolted to the Meteor's structure, the ejection gun being located within the hollow guide rail assembly. Testing of the seat commenced over Chalgrove from EE416 on 19 August 1947, again with Lynch the man in the 'hot seat'. The system worked without problems and the seat was subsequently put into production for installation into the Meteor, Supermarine Attacker, Westland Wyvern, English Electric Canberra and later the Hawker Sea Hawk and de Havilland Venom. EE416 continued its valuable experimental work through the late 1940s and early '50s, racking up some 400 airborne tests in support of the project, including over 20 live test ejections. During this time the company employed a number of other Meteors in support of the project. Meteor Mk 3 EE415 was used as an aerial photographic platform to capture the ejection sequence on film. The ammunition bay was removed and replaced with a forward-angled camera. Flying slightly astern of EE416, the pilot would activate the camera after notification from the test aircraft - however, due to the rapid deceleration of the seat and occupant, only a short sequence could be captured before the subject disappeared from the camera's line of sight. Proving of only marginal use, EE415 was returned to Glosters on the19th October 1949. Two further Meteor F3s (EE338 and EE479) were utilised by Martin-Baker during the late 1940s - the former again for photographic work, and the latter as a ground test rig for ejection trials. Both aircraft were found to be of nominal value and after brief service were returned to the RAE and RAF respectively. Meteor F4 EE519 was also on Martin-Bakers' books for a brief period in 1950-51, but again was found to be surplus to requirements. Approaching the end of its usefulness, EE416 was joined by a Meteor T7 two-seat trainer, WA634. Built in November 1949, the aircraft had a noticeable performance advantage thanks to its Derwent 5 engines, giving it a maximum speed of 585mph. This additional speed would soon prove an advantage in the development of the next generation of seats cleared for use in higher speed ranges. Initial modifications followed along the same lines as for EE416, although this time with the advantage of already being a two-seat design. Modifications included the repositioning of the bulkhead between the two cockpits, strengthening of the floor structure and removal of the flight controls from the rear cockpit. Further modifications were introduced in 1952, when the aircraft returned to Glosters for the fitting of the E.1/44 'high-speed' rear fuselage and tail unit, destined for production Meteor F8s. This configuration was later afforded the designation Meteor T71/2. On return to Martin-Baker in late 1952, the aircraft underwent further modifications before commencing its ejection test career on 31st August 1953. A number of notable first were achieved by WA634 - including the first live runway ejection, by Sqn Ldr J. S. Fifield at Chalgrove on 3rd September 1955. The Meteor was travelling at 145kts and within six seconds of initiating the ejection sequence, Fifield was safely on the ground, having accomplished an ejection which many people had though impossible. The following month Fifield set a new record at the other end of the scale making a successful ejection at an altitude in excess of 40,000ft. With the trials starting on the Martin-Baker rocket-assisted ejection seat it was necessary to determine beforehand what effect the rocket blast would have in a confined cockpit space. For this purpose the company obtained the shell of WA686. In an opposite configuration to WA634, the aircraft comprised the forward fuselage of a Meteor Mk 8 combined with the rear fuselage of a T7 and lacked outer wings, engines and part of the tail section. The aircraft was used for static tests of the rocket-powered seats before the modification of WA634 to begin airborne tests. The first live ejection using a rocket seat was completed by Sqn Ldr Peter Howard in March 1962, who described the ride as 'very smooth'. After WA634 reached the end of its useful life, its work was continued by another Meteor converted to T71/2 standard, WA638. The aircraft continued as the main flying trials aircraft until December 1977. when it was replaced by a further Mk 7'/2, WL419. Named Asterix, WL419 has remained in service up to this day and has now been joined by a resurrected WA638, which made its maiden flight after refurbishment on 29th May 2001. Both aircraft have received additional modifications including external strengthening straps along the fuselage sides and a heavy-duty aluminium blast-tank in the rear fuselage to contain ejection seat rocket blast pressure. The pilot himself is seated in a modern Mk 12L(MBA) ejection seat which fires through a new non-MDC bubble canopy. The continuing use of the Meteor is partly due to the superb serviceability of the aircraft and the centrifugal flow Derwent engines which are extremely resistant to bird strikes. Now in their 57th year of continuous operations with Martin-Baker, the Meteors have a long career in front of them. With only 50 hours or so flying per year, WA638 - as the oldest flying military registered jet aircraft in service in the world - will continue to set new records, and help save more lives for many more years.
On 24 July, after two
final dummy tests were completed, Bernard Lynch ejected himself from EE416 at 320mph and 8,000ft - and thus became the first
person to make a live ejection from an aircraft in the UK. It proved to be landmark event in the history of Martin-Baker,
with the whole system working without a glitch and Lynch making a perfect landing. Unlike the automatic seats of today, Lynch,
once established in a steady descent beneath the main parachute, had to unfasten his seat harness and push himself clear of
the seat, before pulling the ripcord of his own personal parachute, with the seat continuing its descent under the original
'chute. The US Navy JD-1 tests The success of the Martin-Baker system
attracted the interest of the US Navy who, following a presentation to them at Martin-Baker's Denham headquarters, ordered
one of the experimental seats to be fitted in the rear cockpit of a Douglas A-26 Invader. Thus,
the second live ejection from a Martin-Baker seat was made by Lieutenant Adolph "Chubby" Furtek, US Navy, on 1 November
1946 over Lake Hurst, Philadelphia.
Oct 30th Under a project conducted by NAMC Philadelphia, Lieutenant Adolph "Chubby" Furtek (a graduate of
"The Invader
was level at 5000 feet, airspeed 250 mph. As the aircraft
approached NAS Lakehurst, the man in the specially modified aft cockpit again checked his harness and buckles. All was ready.
For Lt A.J. Furtek this would be his 17th leap from an aircraft. More significant,
it would mark his and the US Navy’s first airborne ejection attempt. Furtek reached
over his head and with both hands grasped the face curtain. Erect, tense
in his seat, he pulled the fabric shield forward and down over the upper part of his head. Beneath him
a pair of 600 grain charges exploded. This awesome
slapping force powered a 40 inch piston upward. Lt Furtek, now
a bullet, was on his way. In the next
precious seconds, he recognised something was wrong, the automatic
devices failed to disengage him from the seat, which would have permitted smooth and expeditious opening of the parachute. Later it would
be learned that a fastener on the 28 foot chute attached to the seat had fouled, Furtek tumbled downward four thousand, three thousand, two thousand feet. Twenty three eternal seconds
passed. Finally, by
1500 feet altitude, furtek had disengaged himself from the seat. He pulled the
rip cord of his own parachute. As soon as the
drogue chute blossomed, pulling along the main canopy, he felt a sharp wrenching sensation in his back, his body was briefly thrown into a quarter left turn lateral twist, but the
main chute filled with wing and he fell safely to earth." Martin
Baker
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