Pilot and Seat separation

[Scotteo]

Wasn't too sure were to place this thread but hopefully there's someone with good ejection seat knowledge here.

I'm just a little confused over the harness system. How does the harness go from attaching the pilot to the aircraft to attaching the pilot to the parachute?

I presume its all one harness and that some sort of detachment system is in place to release the inertial reel straps etc. I can't see it being an explosive charge nor can I imagine it to be a guilitine system?

Any clarity would be appreciated

[Green Flash]

I'm sure someone will help you with your specific question but in the meantime check out the website of those unfeasably clever chaps at Martin Baker Martin Baker - Ejection seat and escape system technology

[Blacksheep]

The system that I recall involved a barostatic unit that released the drogues from stabilising the seat and allowed them to pull directly on the parachute to haul the crew member from the seat for a normal descent. The barostatic unit triggered at 10,000 feet (oxygen level) and ran down over two seconds then operated a scissor link to release the drogue from the seat. They had a powerful spring operated bolt and while testing a batch I once advertently omitted the bolt retainer on the test fixture. The bolt fired straight across the workshop and right through the frosted glass wall into the passageway. Thus began my acquaintance with the RAF's last flying Lancaster.

I believe that later baro-release mechanisms use compressed gas to release the scissor link.

[Talk Reaction]

The harness is in fact your parachute harness. When the seat deems it safe for separation a few things happen pretty much at the same time: the scissor shackle opens allowing the drogue to pull out the main chute, also the should retraction parts of the harness are released (clockwork type mech I think, part of the baro time release unit) and the negative g strap is released (similar mech to above and is a strap from the QRF to the seat betwixt your legs (don't know if that's a word). The final 2 places you're held into the seat normally are the leg straps and these are fixed to the seat in spring loaded sticker connections - a good, sharp tug (like what occurs when the main chute opens and rapidly decelerates brave unfortunate Biggles) pulls these out. Thus all that remains to be seen is that the bottom of your parachute meets the top of your harness.......

[Airborne Aircrew]

from the QRF to the seat betwixt your legs (don't know if that's a word)

"Legs" is, most definitely, a word...

As is "Betwixt"... Just so you know...

[dead_pan]

Russian-made seats in action once again:

LiveLeak.com - Iran Air Force SU-24MK Crash.

The pilot & weapon officer seem to leave their seats well before they have reached their maximum height - is there a risk they could be hit by them on the way down?

(not an expert but they seemed to leave it a tad late before deciding they were in fact crashing and that an ejection was called for)

[TEEEJ]

Great website on ejection seat history.

http://www.ejection-history.org.uk/

PROJECT STATEMENT

TJ

[Talk Reaction]

More of a risk of the seat hitting you if you leave it while its still going up I would think (physics not my strongest suit).

I think this is more a case of the pilot/WSO still having the upward vector the seat gave them so they lose none of the 'up' energy and it's about getting the parachute deployed asap at very low level like that. Separation wont occur until after the rocket motor on seat has burnt out so there's nothing to lose in ditching the furniture asap after that

[daze_gone_buy]

Great link

Found this pearl of wisdom in the section about the MB Tie Club
"
Female Pilots

The first female pilot to eject was Lt. Linda Heid on 11 February 1991 and since then The Ejection Tie Club has welcomed a growing presence of women......

Women drivers eh......................

[wz662]

As I understand it a lot of MBs early research was done with the spines and pelvice from cadavers (male) so that they could get the setting of the initial bang correct without killing the pilot. The seat limits were then set for the average (male) pilot.
When female FJ crew came along the earlier research had been forgotton until a 2 stick Harrier crashed with a girl (UAS Cadet) in the back. The doctors treating her were surprised by the lack of back injuries (she had two broken legs but they were from the landing). Looking for a reason it was realised that as women are 'designed' to bear children the lower spine and pelvice are different from the male and as such could take a greater g loading.
No doubt chauvanists will just use this as proof that women are designed to be kicked up the backside

[jimgriff]

Dare I plug my website?
www.ejectorseats.co.uk

It all depends on what seat you are being seperated from really. The latest seats (Mk 10 to Mk 16) use cartridges to generate gas which does things to pistons/cams/detents etc and releases the retraction straps and lap lugs etc thus allowing seat to fall away.
Older seats simply undid the seat harness and the parachute was attached to a seperate harness worn under seat harness. This changed with later Mk 3 seats onwards.
Pulling the manual seperation handle bypasses the system and fires the same cartridges to have the same effect if you need to get out of seat earlier that the system says.
Non martin Baker seats have similar systems but same effect. The Escapac seat (USA) uses a rocket to seperate pilot from seat!!!

[wintys]

Thankyou wz662, laugh? I nearly wet myself!

[Pontius Navigator]

Originally Posted by dead_pan

Russian-made seats in action once again:

The pilot & weapon officer seem to leave their seats well before they have reached their maximum height - is there a risk they could be hit by them on the way down?

Looking at the video, it would appear that both pilots had a positive upward velocity at separation which would enable rapid parachute deployment. Had separation occured at the apogee the parachute deployment would have depended on the drogue and then slowly filled as they accelerated earthward.

With the rapid retardation the unretarded seats continue well out of harms way.

BUT

The effect is often to deposit the aircrew back into the fireball.

(not an expert but they seemed to leave it a tad late before deciding they were in fact crashing and that an ejection was called for)

Probably discussing whether they could afford to pay off the cost of the jet before abandoning it. I know that Middle East students often have to reapy the cost of courses in UK if they fail.

[mr fish]

on a (sort of) related thread, what was the highest performing aircraft
NOT to be fitted with a ejection seat?

i'm thinking ME163, maybe!!

[MAINJAFAD]

Can name at least two. Bell X-1 and DH-108.

[Pontius Navigator]

V-Bomber

[glad rag]

Do those Russian seats "gimbal" or "vector" the rocket efflux??

LiveLeak.com - SU-30MK crash

[ursa_major]

on a (sort of) related thread, what was the highest performing aircraft
NOT to be fitted with a ejection seat?

I'd say the space shuttle.

[MAINJAFAD]

Space Shuttle was fitted with Bang seats. Columbia was fitted with them for her first four launches.

[Double Zero]

The bravest act I ever heard of

WZ662,

Your understanding is completely correct.

I happened by coincidence to be in the Safety Equipment ( seats etc ) bay, Dunsfold, when the telex came through that a Harrier T4 from Wittering had crashed.

It turned out a female student, reckoned to be the first woman RAF fast jet pilot, and an instructor had been flying at around 250', 400+ kts.

They had a birdstike, which took out the instructors' windscreen, along with his intercom, eyes and jaw ( teeth down his throat ).

He couldn't communicate with his passenger, so could only hope she followed her briefing - the traditional " I'll say eject 3 times, the last one you hear will be an echoe ! "

He banged out, luckily she followed.

The aircraft went down in a cornfield, setting fire to it.

He landed OK but badly injured & blind, but she landed in the fire, with broken legs / thighs.

He could hear her screaming, and walked deliberately into the fire, despite being blinded, just homing on her sound, and managed to drag her to safety.

He got some sort of award, but to my mind this is V.C. Material...

All I can remember is the guy's name is Ashley - may be wrong; whoever it was, ' Well Done' is the understatement of the century.