XBradTC

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XBradTC

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Meet your maker in a Martin-Baker

Ejection seats have been a regular component of tactical aircraft since the Second World War. Original seats did little more than propel the pilot high enough to clear the tail in  a bailout. Later seats added improvements, but still were little more than a blank charge firing the seat up the rails. A great leap…

Ejection seats have been a regular component of tactical aircraft since the Second World War. Original seats did little more than propel the pilot high enough to clear the tail in  a bailout. Later seats added improvements, but still were little more than a blank charge firing the seat up the rails. A great leap in capability came with the introduction of the rocket powered seat, which in addition to the catapult gun used a rocket to add vertical vector to the seat’s trajectory, eventually resulting in the “Zero/Zero” seat that could theoretically safely eject a crewmember from a plane with zero airspeed and zero altitude.  But even Zero/Zero seats have limitations. Research, testing, and improved products continue to this day, enlarging the envelope from which aircrew can successfully eject from stricken aircraft. Concurrent with enlarging the successful ejection envelope are developments which seek to minimize the injuries aircrew will sustain in an ejection. For instance, more powerful, longer burning rockets mean a lower initial acceleration vector, which results in fewer spinal injuries. Devices such as restraints to reduce flailing in the windstream also reduce injuries.

Let’s take a look at some of the testing underway for the Martin-Baker seat for the F-35 Joint Strike Fighter.

A successful seat has to get the pilot clear of the airplane and through the canopy. Explosive line charges are used to fracture the canopy. A drogue chute stabilizes the seat, while the seat’s rocket boosts it in altitude. A ballistic charge deploys the main chute.  On some seats, airbags are used to provide separation between the seat and the pilot. A new feature on this seat is airbag curtains to stabilize and protect the pilot’s head and neck.

No, no live pilots featured.* Instead, anatomically functional dummies are used. Sharp eyed observers will notice the tests performed at altitude use a Gloster Meteor as the testbed aircraft- a role it has performed almost from its introduction in the mid-1940s.

*In the early days of ejection seats, live test subjects were actually used.

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  1. Al_in_Ottawa

    The USAF used sedated bears to test ejection capsules for the B58 Hustler.

    Here is probably the most dramatic pic of an ejection seat being used.
    http://www.eyemead.com/noise-1.htm

    Incidentally, a buddy of mine who joined the RAF in ’52 as an engine fitter was told in training that ejection seats thus far had cost more lives than they had saved, due to uncommanded or accidental activation on the ground. Mechanics were quite literally getting shot into the hangar ceiling.

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  2. Joe

    Gloster Meteors for testing? That’s a crime against aviation history.

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  3. Buck Buchanan

    “….anatomically functional dummies.” Describes my current chain of command…and my ex-wife.

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  4. hayabusa69

    I’m glad they’re putting a good ejection seat in the F-35. I have a feeling the pilots are going to need them.

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  5. Jeff

    “A successful seat has to get the pilot clear of the airplane and through the canopy. Explosive line charges are used to fracture the canopy.”

    Not all escape systems require going through the closed canopy. On many aircraft, the canopy is jettisoned before the seat leaves. I’ve flown in eight different kinds of aircraft with ejection seats and all of them jetisoned the canopy first…or would have if I’d had to eject.

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  6. xbradtc

    You’re correct, of course. I didn’t have time to write a complete history of ejection seats (or even touch on capsules!).

    The method is specific to each aircraft.

    As an example, the A-6 Intruder had the preferred method of jettisoning the canopy, but the crew could eject through the canopy. There was no explosive line charge, but rather a set of “breaker arms” on the top of each seat to shatter the canopy as the seat rode up the rails.

    Some older aircraft didn’t have any option but to jettison the canopy. Often, that was an integral part of the firing process, but in some aircraft it was a distinct, separate operation.

    Initially, ejection systems were seen as a way of safely exiting high speed aircraft at altitude. Such a two-step process for ejection wasn’t seen as a great problem. But as it quickly became clear that the majority of failed ejections were at low speed and low altitude, simplifying and expediting the deployment for the crew came to be more and more critical.

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  7. SFC Dunlap 173d RVN

    Somewhat oddly, ejection seats were used commonly on one US Army aircraft, the OV-1 Mohawk and it was a Martin-Baker. The canopy had an odd pack recycle period compared to other personnel parachute canopies.

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  8. Esli

    Did you ever read about that Intruder with a partial ejection of the B/N, and he rode all the way down to the flight deck projecting through the shattered canopy? Crazy but true. All kinds of info online. Here is a video of the trap. http://www.youtube.com/watch?v=Z6DQEPIWLFc

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  9. xbradtc

    Read about it several times, but I don’t think I’ve ever blogged about it.

    http://www.gallagher.com/ejection_seat/

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  10. Terry Lomax. ex-RN.

    One of the main reasons for the development of ejecting through the canopy, with the aid of the explosive “Miniature Detonator Cord” (MDC) to shatter the canopy, was the increasing development of high speed low level strike aircraft like the Blackburn Buccaneer. On many earlier seats the Barometric Time Release Unit (BTRU) would prevent aircrew separation from the seat at speeds in excess of 300 knots (as well as too great an altitude), but with an aircraft that would specialise in attacking a target at very low level (down to 50 ft.) and at high subsonic speed (450 – 500 mph), smash through canopies and instant ejection (no time delay on the main ejection gun firing unit) become a necessity for aircrew survival.

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