afrikaskyes
Posts: 118
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Are Ejection Chutes Guidable

Sat Nov 25, 2006 8:51 am

An airport fire fighter just explained to me that he responded to an F-16 crash that killed the pilot because he said the pilot ejected but the chute steered him into the inferno. I asked him why ejection chutes aren't controllable and he didn't know why. Does anyone have an answer for us?
 
usnseallt82
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RE: Are Ejection Chutes Guidable

Sat Nov 25, 2006 8:58 am

Quoting Afrikaskyes (Thread starter):
I asked him why ejection chutes aren't controllable and he didn't know why. Does anyone have an answer for us?

Some are, some aren't. It depends upon what type will fit in the seat and which one the military decides on.

From what I know, outside of some older model seats, most in the U.S. inventory are steerable. At least as far as the Navy's concerned. However, I'm sure there are some standard chutes out there without risers.
Crye me a river
 
DeltaGuy
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RE: Are Ejection Chutes Guidable

Sat Nov 25, 2006 9:01 am

Alot of ejection chutes aren't controllable, other than grabbing the risers and holding on for dear life.

An ejection is extremely violent- in under three seconds you go from sitting in a cockpit to dangling under a fully inflated canopy. The parachute is much smaller in diameter than, say a standard aerobatic or paratrooper parachute (one that can actually be controlled), so you tend to fall faster with these. In many cases, as I'm sure was the case with the F-16 pilot you mentioned, alot of these ejections are so low that there's no delay in the sequencing and getting the pilot under a fully inflated canopy is the only thing that matters- imagine ejecting at ground level and trying to steer the chute with only several feet to spare by the time your chute was open.

I've heard of alot of cases where the pilot will literally end up right back where he came from, landing within feet of the cockpit- oftentimes engulfed in flames.

DeltaGuy

[Edited 2006-11-25 01:02:12]
"The cockpit, what is it?" "It's the little room in the front of the plane where the pilot sits, but that's not importan
 
f4wso
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RE: Are Ejection Chutes Guidable

Sat Nov 25, 2006 10:19 am

The two ejection seats I have been trained in were the T-37 and F-4. Both had the 28 foot round canopies that had a four line jettison for rudimentary steering. The T-37 had a backpack, the Martin-Baker in the Phantom had the canopy mounted on the seat in a horseshoe shaped container. Fortunately, I don't have any practical experience with either version.

My early skydiving was with the T-10 round canopies used by the US Airborne troops. I always considered the steering toggles on that more view toggles than for steering, changing the direction I was looking compared to covering any ground. In fact it was only 5-7 mph across the ground vs the newer square canopies that I used before my new wife said no more jumping.

Gary
Cottage Grove, MN, USA
Seeking an honest week's pay for an honest day's work
 
bushpilot
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RE: Are Ejection Chutes Guidable

Sat Nov 25, 2006 10:52 am

Quoting DeltaGuy (Reply 2):

This immediately made me think of the somewhat famous footage of an F-14 coming in for a carrier night landing. The tail end of the bird hit the aft of the ship. Both ejected from 0 altitude one managed to clear the fire, but the other(I am not sure if it was the pilot or backseater) landed right in the fire. It is not a matter steering when you eject from that low, you land where gravity, wind and the force of the ejection want you to.
 
CTR
Posts: 299
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RE: Are Ejection Chutes Guidable

Sat Nov 25, 2006 11:49 am

Twenty years ago I used to work with Stencel and MB ejection seats. With Zero-Zero seats one of the biggest engineering challenges is getting the chute to fully deploy in the shortest possible time and achieve the maximum drag for deceleration.

Round canopys perform best for speed of deployment and drag. Adding panels and toggles to provide steering to a round canopy work against both speed of deployment and drag.

Have fun,

CTR
Aircraft design is just one big compromise,,,
 
usnseallt82
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RE: Are Ejection Chutes Guidable

Sat Nov 25, 2006 1:24 pm

Quoting CTR (Reply 5):
With Zero-Zero seats one of the biggest engineering challenges is getting the chute to fully deploy in the shortest possible time and achieve the maximum drag for deceleration.

This is something that we used to brief out the ass about. While the 0/0 concept is nice, if you aren't pegged in that operating envelope for it to work right, it simply won't work right. A lot of times guys get complacent with thinking that all ground emergencies can be covered by one bold face...EJECT. You just can't assume that it'll work perfectly with nothing more than the rocket boosting you up.

Anyway, point being....I can imagine how hard it would be to design that.
Crye me a river
 
bhmbaglock
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RE: Are Ejection Chutes Guidable

Sat Nov 25, 2006 1:50 pm

CTR makes some good points regarding rounds. The gist of it is that any provisions for steering a round will weaken the ultimate strength of the canopy. Some designs to speed canopy openings even employ high drag devices on the rear of the canopy to decrease opening time - the exact opposite of the normal modifications used to enable steering.

An experienced canopy pilot can get some steering out of a true round(or more likely conical) parachute particularly if it has four risers but it takes skill and strength. With good timing and some luck you can even get a bit of a flare out it but if you mis-time it you'll do more harm than good.

The USN has tested ram-air(square) parachutes for ejection seats. The results were good as I recall but I don't see them being put into operational use any time soon due more to training/psychological issues rather than any engineering issues. They're much more steerable, land much more softly, etc. but can also very easily kill you if you don't really know what you're doing.

I know that many pilots have made parachute jumps but the majority find the very concept to be distasteful. Simply put, I believe that very few pilots are willing to make parachute jumps for training purposes and it's an absolute necessity to safely use a square parachute. A lot of progress has been made over the last decade in simulators that could very well meet needs for currency training but a few real jumps up front are really necessary to get the real feel for how it works.

As an example, Strong Enterprises makes a very nice pilot's rig for jump pilots and aerobatics that has an option for a square canopy. They will not deliver it to the purchaser without a minimum of two tandem jumps IIRC.
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usnseallt82
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RE: Are Ejection Chutes Guidable

Sat Nov 25, 2006 1:57 pm

Quoting BHMBAGLOCK (Reply 7):
A lot of progress has been made over the last decade in simulators that could very well meet needs for currency training but a few real jumps up front are really necessary to get the real feel for how it works.

The ones we have now are decent, but primitive at best. They consist of a cage like box where you strap up and hang from your harness. Then you put on virtual reality-type goggles that show a view of the horizon. You then try to steer from there.

It works as far as getting you familiar with the equipment, but not much more than that.
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SlamClick
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RE: Are Ejection Chutes Guidable

Sun Nov 26, 2006 3:12 am

If you eject anywhere near the scene of the crash a steerable chute may be irrelevant.

The fireball from the crash is going to create a huge local thermal and it is going to burn the oxygen out of the nearby atmosphere. The oxygen, about 21% of the volume of the air is going to be replaced by air rushing in TOWARD the fire from all directions. If you get caught in this current you will be pulled into the thermal and sucked up into the fireball. Steerable chutes don't generate enough forward velocity to escape it.

I little distance away - a different ballgame.

Perhaps if you are thinking it may be time to eject - it used to be. Now it is too late?

The exterior views and the cockpit cam are available on the net, from the Thunderbirds crash in Idaho a couple of years ago. He probably escaped that in part because the plane, despite being committed to striking the ground, did have a lot of forward velocity. Thus, the burning jet fuel was carried away from him by momentum. If he'd been at a steeper angle, less forward momentum at the moment of impact, the outcome might have been different.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
usnseallt82
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RE: Are Ejection Chutes Guidable

Sun Nov 26, 2006 4:53 am

Quoting SlamClick (Reply 9):
Perhaps if you are thinking it may be time to eject - it used to be. Now it is too late?

I think this is one of the main factors right here.  checkmark 

If you eject, the sheer shock of the actual event is enough to momentarily stun you, no matter how much training you've had. It'll take a few seconds to get your composure and by then it might be too late. Especially, like you said later on, if the forward momentum isn't enough to give you much time before coming back down on the wreckage.

This is why they tell those in ejection seat aircraft that when all else fails, eject. Don't try to think about it, just eject. The plane can be replaced, the pilot cannot.
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UH60FtRucker
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RE: Are Ejection Chutes Guidable

Sun Nov 26, 2006 6:36 am

Quoting Usnseallt82 (Reply 10):

Hey do they have ejection seats in those flying living rooms you work on?  Wink

-UH60
Your men have to follow your orders. They don't have to go to your funeral.
 
usnseallt82
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RE: Are Ejection Chutes Guidable

Sun Nov 26, 2006 6:41 am

Quoting UH60FtRucker (Reply 11):
Hey do they have ejection seats in those flying living rooms you work on?

Hell no. Some bright one way back in tha' day decided that if one of those turds is going down, we'll have enough glide time to bail out with chutes on our backs. Of course, that's assuming that every one of us can pull our heads out of our asses in time to strap on the harness and actually get out the door in an orderly fashion.

I think its just for morale.  yes 
Crye me a river
 
UH60FtRucker
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RE: Are Ejection Chutes Guidable

Sun Nov 26, 2006 6:49 am

Quoting Usnseallt82 (Reply 12):
I think its just for morale.

Really?

Because you see... I think it's because El Al flights operate in a more dangerous environment, than you.  Wink

So if I ever fly on board your bird, will you bring me some peanuts and fluff my pillow? And what's the IFE options like?  Wink

-UH60
Your men have to follow your orders. They don't have to go to your funeral.
 
usnseallt82
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RE: Are Ejection Chutes Guidable

Sun Nov 26, 2006 6:56 am

Quoting UH60FtRucker (Reply 13):
I think it's because El Al flights operate in a more dangerous environment, than you.

Try flying next to China someday.  yes 

Quoting UH60FtRucker (Reply 13):
And what's the IFE options like?

Open the free fall chute.....wank away. Afterwards, wash your damn hands and fetch me a f**kin' drink.  Big grin
Crye me a river
 
MissedApproach
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RE: Are Ejection Chutes Guidable

Sun Nov 26, 2006 10:58 am

Quoting Afrikaskyes (Thread starter):
I asked him why ejection chutes aren't controllable and he didn't know why.

AFAIK most of them aren't, probably due to space & weight limitations. Pilots ejecting on the ground or in landing accidents have landed in their own flaming wreckage at a disappointing rate, but I suppose it's better than nothing.
There's a lot of excellent & detailed info here: http://www.ejection-history.org.uk/index.htm
Can you hear me now?
 
DeltaGuy
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RE: Are Ejection Chutes Guidable

Mon Nov 27, 2006 1:26 am

Quoting CTR (Reply 5):
Twenty years ago I used to work with Stencel and MB ejection seats.

You didn't happen to work on the SJU-8A did you? What other MB's did you work on?

DeltaGuy
"The cockpit, what is it?" "It's the little room in the front of the plane where the pilot sits, but that's not importan
 
CTR
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RE: Are Ejection Chutes Guidable

Mon Nov 27, 2006 2:36 am

DeltaGuy,

I worked on the TAV8-B Harrier (Stencel seats) and the GRMk5 Harrier (Martin Baker seats). Later I worked on a Navy stealthy attack aircraft that never made it to production. But it would have used MB seats. We had to go through Hell with security to get a non USA component on a classified aircraft. The only other non USA component was the Dowty repeatable hold back bar.

Sorry, it's been to many programs and years to remember the MB seat model numbers. But I do remember my 2 week stay at the China Lake SNORT track blowing up canopys.

Have fun,

CTR
Aircraft design is just one big compromise,,,
 
high_flyr69
Posts: 497
Joined: Mon Apr 30, 2001 6:19 am

RE: Are Ejection Chutes Guidable

Thu Nov 30, 2006 7:05 pm

As an aircraft life support fitter in the RAAF i have found the only steering for aircrew after ejection is the stability provided by the PSP pack after it is released from the seat on descent. The psp counteracts the corkscrew effect associated with descent with round parachutes, the sound of the PSP hitting the ground is also one of the best indicators for aircrew to brace for impactwith the ground as there is usually 10 meters (30 or so feet) between the pilot in his seat and the PSP below him.

Hope that was of some interest
cheers
high_flyr69
Diplomacy is the art of saying 'Nice Doggy' until you find the shot gun
 
DeltaGuy
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RE: Are Ejection Chutes Guidable

Mon Dec 04, 2006 12:34 pm

CTR,

Sounds like you've had your share of experience with escape systems!

Question for you (off topic)...you know anything about the GRU-5 seat, flew in the A-6A. I'm restoring one and unfortunately really only have one photo of it in service, most were replaced by the GRU-7 in the early 70's...I've only seen the GRU-5 once, other than my own.

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Photo © Jerry Dooley



Thanks for the info,
DeltaGuy
"The cockpit, what is it?" "It's the little room in the front of the plane where the pilot sits, but that's not importan

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