# Downwards ejection seats: the arguments in favour of them



## msxyz (Jul 24, 2021)

Downwards ejection seats were employed in a few aircrafts of the '50s but they disappeared once the upwards firing ejection seats reached a certain maturity.

It's often assumed that engineers developed this method of abandoning an airplane solely because, above a certain speed, upwards ejection seats would not guarantee that the occupant will avoid an impact with the vertical rudder. And yet there must be other advantages that such system would have.

-Less energy involved. Ejecting upwards means that both gravity force and the airstream wash are pushing you against the fuselage (not to mention the looming vertical rudder at the back). Ejecting downwards gravity and air pressure are actually helping you gaining some distance from the plane.

-Less stressful on internal organs and spinal cord: as a consequence of the first point, you don't need a very powerful and sudden thrust to leave the cabin. The direction of the thrust also does not compress the spinal cord and the organs.

-Simple/More reliable? I'm thinking about the fact that also the canopy (or the cabin's roof) must be jettisoned. It means another ejection mechanism that must activate split seconds before the seat . A trapdoor unlocking and opening backwards (or being pushed by the seats itself) looks a simpler and more reliable mechanism.

Are there any other points I've missed?


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## SaparotRob (Jul 24, 2021)

The only thing I can think of is the problem of very low altitude ejection with a downward ejection seat.


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## msxyz (Jul 24, 2021)

SaparotRob said:


> The only thing I can think of is the problem of very low altitude ejection with a downward ejection seat.


Sure: that's why you read that downwards firing ejection seats were unpopular with the crews. (Yet you don't hear any complaint by civil pilots about NOT having any ejection seat at all  ). The minimum altitude for downwards firing ejection seats is around 1000ft or 300m which makes these seats not very useful for a botched take-off/landing and almost useless for carrier based aircrafts where most of the accidents happen at these times.

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## cvairwerks (Jul 24, 2021)

Can't make a downward seat zero/zero.... Also the downward seats from the 50's and 60's had minimum altitude restrictions, something like above 500 feet for the B-47. Don't know offhand what the requirements were for the early F-104 and the B-52 downward seats.


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## msxyz (Jul 24, 2021)

This is a picture of the Tu-22's seats for the crew (front to back: bomber, pilot, navigator). The trapdoors at the bottom were also used to enter the plane: the seats were lowered to allow the men to climb onto them. The Tu-22 was not the sole Russian aircraft employing a similar scheme.

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## GrauGeist (Jul 24, 2021)

Can't think of how many pilots right offhand, that were saved by upward ejections during last minute punch-outs at airshows alone, but it's quite a few.

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## Graeme (Jul 24, 2021)

Bounder was another downward tosser...maybe when you hit the ground, you just 'Bounded' along?

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## Graeme (Jul 24, 2021)

Interestingly, Bear had a conveyor belt...

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## msxyz (Jul 25, 2021)

Graeme said:


> Bounder was another downward tosser...maybe when you hit the ground, you just 'Bounded' along?



This nice model of the Myasischev M-50 shows how high those seats hanged from the bottom of the nose 






If I had to fly that plane, I would have brought with me a long rope, just in case 



Graeme said:


> Interestingly, Bear had a conveyor belt...



Another Myasischev plane, the M-4 had a similarly convoluted ejection scheme. There were five different escape hatches on the lower part of the fuselage, one of which was shared by the pilot, co-pilot and navigator which were ejected downwards in quick succession by a pneumatic system which shuffled the seats around. Other members of the crew had their own escape hatch, each equipped with a downwards firing ejection seat. (The plane also had a couple of hatches on the roof, for ditching at sea or belly landings).

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## SaparotRob (Jul 25, 2021)

That is a beautiful model. I've always liked the appearance of that plane. It has a certain "Gerry Anderson, When the Future was Fab" aesthetic to it.

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## Glider (Jul 25, 2021)

The only observation I can make is one that others have mentioned. most accidents happen on take off and landing. Being fired into the tarmac doesn't give me a lot of confidence

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## Thumpalumpacus (Jul 25, 2021)

Graeme said:


> Bounder was another downward tosser...maybe when you hit the ground, you just 'Bounded' along?
> 
> View attachment 633414



Man, that thing's almost tall enough for those seats to be zero-zero.


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## FLYBOYJ (Jul 25, 2021)

msxyz said:


> Downwards ejection seats were employed in a few *aircrafts* of the '50s but they disappeared once the upwards firing ejection seats reached a certain maturity.
> 
> *Are there any other points I've missed?*


A few things - "Aircraft" is both singular and plural. "Aircrafts" is not a word.


msxyz said:


> Yet you don't hear any complaint by civil pilots about NOT having any ejection seat at all


Ejection seats were designed to remove the pilot from an aircraft that has or will become uncontrollable and more than likely that's going to happen in combat. Military aircraft generally don't glide well so if you have a low level catastrophic engine failure your options are minimal. Most civil aircraft are not going to have that need of emergency egress because the odds of a catastrophic structural failure that would render the airframe unflyable is at a minimum unless you're flying an aerobatic aircraft. I've flown in military aircraft with hot seats and I can tell you I had no intension of punching out unless I saw a wing depart the aircraft. I'll let some of our more military jocks chime in on this. The only GA aircraft with an egress system is the Cirrus SR20/22 series with their ballistic chute (CAPS) system and the only reason this was incorporated was because the aircraft was not put through spin testing during certification. It became a great sales feature.

Downward ejection seats are great at altitude, I think this point is obvious.

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## Barrett (Jul 26, 2021)

I've known a few 104 aviators, and none were very enthused about ejecting downward. But evidently when the Starfighter was developed, there was concern about existing seats clearing that relatively tall T-tail...






The Ejection Site: F-104 Ejection Seats


Everything you {n}ever wanted to know about Ejection Seats!!!



www.ejectionsite.com

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## SaparotRob (Jul 26, 2021)

That was a good read.


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## FLYBOYJ (Jul 26, 2021)

That's a great site, everything you ever wanted to know about ejection seats. 

The Stanley Aircraft Corp. facility in Aurora is still standing, today it's a fancy mall.

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## SaparotRob (Jul 26, 2021)

At least the building is still there!

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## msxyz (Jul 27, 2021)

FLYBOYJ said:


> I've flown in military aircraft with hot seats and I can tell you I had no intension of punching out unless I saw a wing depart the aircraft.


You're not the first pilot that says this and I can understand why. I'm no pilot myself but an engineer and, looking at how they work, I can appreciate why they're truly a 'last ditch' option.



> Downward ejection seats are great at altitude, I think this point is obvious.



They seem to be much better than upwards firing seats in term of safety and comfort. Of course, they are also useless during take off and landings, or during very low altitude manoeuvres. Maybe somebody should try to patent an "all aspect" ejection seat that fires you upwards or downwards depending on the altitude and plane orientation (and with a different acceleration depending on the direction)!

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## cvairwerks (Jul 27, 2021)

Seat design and operation limit determination is one heck of an engineering task for single direction launch. Adding a second direction would magnify the task significantly. The ACES2 and US-16E cover essentially every survivable launch parameter a pilot might get into. Zero/Zero seats when activated, read all the necessary data, run the launch determination calculations, process the decision and start the launch cycle0, all in a matter of microseconds. From sequence initiation to having the crew member on a chute is under 2 seconds for almost every seat design. Consider too, that depending on the seat and aircraft combination, there could be as many as 30-40 separate actions that have to happen in the correct sequences and timing windows to make a successful ejection.
It’s one area where it really is rocket science! Supersonic ejection falls into a class all by itself.

Many years ago, my ultimate boss was fatally injured in an accident. He ejected well outside the parameters of the ACES2, and nearly made it. The differences for him between success and death was less than 1 second within the window of the decision to eject and actually initiating the sequence.

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## Glider (Jul 27, 2021)

msxyz said:


> They seem to be much better than upwards firing seats in term of safety and comfort. Of course, they are also useless during take off and landings, or during very low altitude manoeuvres. Maybe somebody should try to patent an "all aspect" ejection seat that fires you upwards or downwards depending on the altitude and plane orientation (and with a different acceleration depending on the direction)!


I think it was the Russians who first designed a seat that if it was fired and the aircraft was at an angle. The seat would 'recognise' the problem and automatically adjust the seat so it would climb.

Certainly could be wrong but I have something in the back of my mind on that. 

The much maligned Yak 38 had an automatic firing ejector seat if the pilot got into difficulties at landing

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## gumbyk (Jul 27, 2021)

msxyz said:


> Less stressful on internal organs and spinal cord: as a consequence of the first point, you don't need a very powerful and sudden thrust to leave the cabin. The direction of the thrust also does not compress the spinal cord and the organs.


It may produce less stress on the spine, etc, but more strain on the blood vessels in the eye and brain. Even -3g can cause damage to the eyes (retinal detachment, burst blood vessels), so at ejection forces (even downwards) you may be at risk of bursting major vessels in the brain.

Also, don't forget that the aircraft's trajectory is downwards - ideally you want to be above that. An aircraft in a spin has very little or no forward velocity to carry it away from a pilot under a chute.

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## Joe Broady (Jul 29, 2021)

msxyz said:


> -Simple/More reliable? I'm thinking about the fact that also the canopy (or the cabin's roof) must be jettisoned. It means another ejection mechanism that must activate split seconds before the seat . A trapdoor unlocking and opening backwards (or being pushed by the seats itself) looks a simpler and more reliable mechanism.


I'm skeptical about that. In the B-52, for instance, all six ejection hatches have an initiator which fires when the hatch departs, thereby arming the seat. This safety feature prevents the seat from firing if the hatch fails to jettison. If the hatch initiator malfunctions, there's a "pin pull" control on the seat to override the initiator — after you make sure the hatch has departed! So in the B-52, at least, the ejection sequence involves a sequence of automatic steps whether the ejection is upward or downward.

The flight manual warns that if a downward ejection hatch is dropped when the plane is on the ground, the seat is armed and can fire.

Minimum downward ejection altitude is 800 feet in the B-47. In the B-52 you can escape successfully from 250 feet if the plane is not descending with respect to terrain and has at least 120 knots airspeed.

I don't know what's below the floor in a fighter, but I imagine a downward ejection system would impose annoying constraints on the layout of cables, plumbing, and linkages since there has to be a clear space for the hatch. Also, the structural design has to carry load around the hatch opening unless the hatch is a stressed, load-carrying component.

References:
1B-47E-1, Flight Handbook, USAF Series B-47B and B-47E Aircraft, 30 December 1955.
1B-52H-1, B-52H Flight Manual, 30 July 1980

A safety supplement in the B-52 manual warns that the 250 foot figure is valid only if the downward ejection seat is full forward. If not, the drogue parachute mechanism can be damaged during ejection. The man-seat separator is not affected, but without help from the drogue chute you must be at least 400 feet above ground. That was in 1980; I assume the deficiency has been corrected.

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## msxyz (Jul 30, 2021)

Very informative post and interesting considerations. A downwards ejection seat wouldn't be possible in a plane where the wheel well is located under the cabin, or if there is an air intake. Also, the levers connected to the pedals and the yoke/stick would have to be routed around the hatch resulting in a more complicated arrangement.


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## nuuumannn (Aug 5, 2021)

Glider said:


> The much maligned Yak 38 had an automatic firing ejector seat if the pilot got into difficulties at landing



Yeah, initially this happened quite often, well comparatively as there weren't that many aboard the carriers, but Yak developed an autoland system for the aircraft, which was quite effective. It's worth remembering that the Yak-38 was not meant to be operated as a standalone aircraft, like the Sea Harrier, but as a weapons system employed from the carrier, which, strictly speaking is an Anti-Submarine Warfare Cruiser deployed with a specific role as part of a task force. The Yak-38s were to carry out strike operations against shipping and had a limited IR AAM capability. Nonetheless, it was limited in range and thus payload carrying capability.

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## msxyz (Aug 9, 2021)

This drawing depicts the downwards ejection system of a soviet bomber (possibly the Tu 22). The pilot's and the other guy's seat slides on rails though a long shaft before being ejected. What a fun ride must have been!

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## T Bolt (Aug 9, 2021)

I read somewhere pilots of the early F-104s were told that in case of an engine failed at take off they were to roll the aircraft upside down and eject.


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## gumbyk (Aug 9, 2021)

T Bolt said:


> I read somewhere pilots of the early F-104s were told that in case of an engine failed at take off they were to roll the aircraft upside down and eject.


That would likely just delay the inevitable. Excessive negative G, and trying to deploy the chute while 'inverted' is never going to end well. If they were told that, it was just to make them feel better.

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## Thumpalumpacus (Aug 9, 2021)

gumbyk said:


> That would likely just delay the inevitable. Excessive negative G, and trying to deploy the chute while 'inverted' is never going to end well. If they were told that, it was just to make them feel better.



The drogue chute isn't directional, is it? F-104 is before my time, but so far as I understand, the drogue-chute just goes in the wind to pull out chute, no matter the direction. And inverted and diving in would impart positive-G, no? 

Am I missing something here?


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## gumbyk (Aug 10, 2021)

Thumpalumpacus said:


> The drogue chute isn't directional, is it? F-104 is before my time, but so far as I understand, the drogue-chute just goes in the wind to pull out chute, no matter the direction. And inverted and diving in would impart positive-G, no?
> 
> Am I missing something here?


Most ejection seats at that time had limitations on bank, as the drogue doesn't come out immediately.

You'd still impart quite a few G on your body ejecting downward, add 2 more if the aircraft was inverted and punching out the bottom, even if you were positive during the dive. Generally the human body isn't as resilient to negative g as positive. e.g. retinal detachment can occur as low as -3g.

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## msxyz (Aug 10, 2021)

I think downwards firing ejector seats need to impart a much weaker thrust, not only because gravity is lending a hand but also because there is no tail to clear. The seat just needs to be pushed outside the aircraft, like a bomb or missile from an internal bay. But if the thrust is weak, ejecting upside down could cause the pilot to strike the fuselage due to the combined action of gravity and the airflow.


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