henry@zoo.toronto.edu (Henry Spencer) (07/13/89)
From: henry@zoo.toronto.edu (Henry Spencer) >... TV film of the MiG-29 (Fulcrum) crash at the Paris >Airshow '89 showed that the plane was heading vertically for the ground when >the pilot ejected at what must have been 50 - 100'. Upon leaving the plane the >seat righted itself and deployed the chute immediately. It hadn't opened fully >before hitting the ground but must have provided some breaking as the pilot >bounced once but virtually walked away from the crash... Aviation Week says the ejection was at about 300 feet, in fact. On the other hand, the aircraft was inverted in a near-vertical dive, which is rather worse than inverted in level flight. It's amazing that the pilot survived, let alone with nothing more than cuts and bruises. Henry Spencer at U of Toronto Zoology uunet!attcan!utzoo!henry henry@zoo.toronto.edu
welty@lewis.crd.ge.com (richard welty) (07/20/89)
From: welty@lewis.crd.ge.com (richard welty)
In article <8226@cbnews.ATT.COM>, Henry Spencer writes:
*Aviation Week says the ejection was at about 300 feet, in fact. On the
*other hand, the aircraft was inverted in a near-vertical dive, which is
*rather worse than inverted in level flight. It's amazing that the pilot
*survived, let alone with nothing more than cuts and bruises.
it suggests that there has been a major improvement in Soviet
ejection seats; the seats on the early Mig 21 aircraft were
possibly more dangerous to the pilots than staying in the craft.
richard
--
richard welty welty@lewis.crd.ge.com
518-387-6346, GE R&D, K1-5C39, Niskayuna, New York
Officer: Do you know how fast you were going?
Driver: No. The speedometer only goes up to 85alan@decwrl.dec.com (Alan Hepburn) (02/04/91)
From: voder!nsc!dtg.nsc.com!alan@decwrl.dec.com (Alan Hepburn) There's been talk recently about the injuries of the Allied POWs being caused by the act of ejecting from their planes. Some people have said that some planes are designed such that the pilot must eject through a closed canopy. It seems to me that a canopy designed to withstand air pressures of supersonic flight would be extremely difficult to punch through with a slow-moving seat, or head. Does anyone out there have any real data on this? Can a pilot survive a punch out through a canopy? -- Alan Hepburn "To treat your facts with imagination National Semiconductor Corp is one thing, but to imagine your facts Santa Clara, Ca is anothor." mail: alan@berlioz.nsc.com John Burroughs
henry@zoo.toronto.edu (Henry Spencer) (02/05/91)
From: henry@zoo.toronto.edu (Henry Spencer) >From: voder!nsc!dtg.nsc.com!alan@decwrl.dec.com (Alan Hepburn) >There's been talk recently about the injuries of the Allied POWs being >caused by the act of ejecting from their planes... Ejection injuries, up to and including fractured vertebrae, are not at all uncommon. Ejection is a very violent process, undertaken only when the alternative looks even worse. >Some people have >said that some planes are designed such that the pilot must eject through >a closed canopy. It seems to me that a canopy designed to withstand >air pressures of supersonic flight would be extremely difficult to >punch through with a slow-moving seat, or head... The typical approach taken in through-the-canopy-ejection aircraft is to make the thick windshield on the front -- which has to contend with high aerodynamic forces plus birdstrikes -- a separate piece from the relatively thin overhead canopy. This does mean putting a frame of some kind between the two, which obstructs the pilot's vision somewhat. On the other hand, it permits truly instantaneous ejection, while jettisoning the canopy before ejection involves a delay. At low altitude that delay could be fatal. There are various intermediate approaches like putting detonating cord in the canopy so it can be shattered as ejection begins. I believe it is also relatively normal for modern seats to be tall enough that they hit the canopy before the pilot's head does. Don't underestimate the forces involved. >... Can a pilot survive a punch out through a canopy? Yes, definitely. RAF combat aircraft are almost entirely eject-through- canopy types, since the RAF stresses the low-altitude penetration role and demands instantaneous ejection. -- "Maybe we should tell the truth?" | Henry Spencer at U of Toronto Zoology "Surely we aren't that desperate yet." | henry@zoo.toronto.edu utzoo!henry
bxr307@csc.anu.edu.au (02/05/91)
From: bxr307@csc.anu.edu.au In article <1991Feb4.052511.15316@cbnews.att.com>, voder!nsc!dtg.nsc.com!alan@decwrl.dec.com (Alan Hepburn) writes: > > > From: voder!nsc!dtg.nsc.com!alan@decwrl.dec.com (Alan Hepburn) > > There's been talk recently about the injuries of the Allied POWs being > caused by the act of ejecting from their planes. Some people have > said that some planes are designed such that the pilot must eject through > a closed canopy. It seems to me that a canopy designed to withstand > air pressures of supersonic flight would be extremely difficult to > punch through with a slow-moving seat, or head. Does anyone out there > have any real data on this? Can a pilot survive a punch out through > a canopy? Most modern, high-speed aircraft now have ejector seats which force their way through the canopy. This is necessary because at supersonic speeds there is little time to wait for a canopy to be ejected clear from the aircraft and then have the seat eject a second later. It was deemed faster to simply either destroy the canopy or to break through it. British aircraft are equipped with exploding canopies which have detonating cord moulded into their clear plastic so that when the time to eject comes this is exploded a split second before the seat is ejected from the aircraft, clearing a way for it. The det-cord appears as a thin black line in the canopy and while partially obscuring vision for the pilot it is felt that safety comes first (and anyway the argument runs, the pilot will be focusing on objects in the middle and far distance and the det-cord will be nearly invisible to him). Other nationalities tend to go for "canopy-cutters" atop the head rest of the seat (basically a sharp edged structure which is designed to destroy the canopy by brute force as the seat ejects) as they are uncomfortable with the idea of several pounds of explosive within a few inches of the head of the pilot. As to which is the better system, I think it is mainly horses for courses. Each airforce has its personal preference and believes its better than the other's. Both have disadvantages. The det-cord has no backup if it fails to destroy the canopy. The canopy-cutters have the disadvantage that the canopy has to be made weaker to allow them to work, and as such it is far less resistant to other things, like birdstrike. Brian Ross
baldwin@cad.usna.mil (J.D. Baldwin) (02/06/91)
From: "J.D. Baldwin" <baldwin@cad.usna.mil> bxr307@csc.anu.edu.au (Brian Ross) writes: >> [quoting Alan Hepburn] >> There's been talk recently about the injuries of the Allied POWs being >> caused by the act of ejecting from their planes. Some people have >> said that some planes are designed such that the pilot must eject through >> a closed canopy. It seems to me that a canopy designed to withstand >> air pressures of supersonic flight would be extremely difficult to >> punch through with a slow-moving seat, or head. Does anyone out there >> have any real data on this? Can a pilot survive a punch out through >> a canopy? > > Most modern, high-speed aircraft now have ejector seats which force >their way through the canopy. > [various excellent discussion of methods deleted] Not that it qualifies as "high-speed" by most standards, but the mighty S-3A Viking, carrier-based ASW jet, punches its four aircrew through the canopy. Though the canopy is rigged with "det cord," it is not used in the ejection sequence (it is there only for the purpose of "blowing" the canopy independent of ejection). Instead, the top of the ejection seat is equipped with a "breaker bar" which simply punches a hole in the canopy, about half a millisecond before one's head. I recall that this made me very, very nervous, but I know several men who've done it, and it wasn't an issue. -- From the catapult of: |+| "If anyone disagrees with anything I _,_J. D. Baldwin, Comp Sci Dept |+| say, I am quite prepared not only to _|70|___:::)=}- U.S. Naval Academy|+| retract it, but also to deny under \ / baldwin@cad.usna.navy.mil |+| oath that I ever said it." --T. Lehrer ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pd@sics.se (Per Danielsson) (02/06/91)
From: pd@sics.se (Per Danielsson) In article <1991Feb5.040231.3928@cbnews.att.com>, henry@zoo (Henry Spencer) writes: >Ejection injuries, up to and including fractured vertebrae, are not at all >uncommon. Ejection is a very violent process, undertaken only when the >alternative looks even worse. Swedish Air Force pilots are grounded after a certain number of ejections (I believe the number is three) since they are at to great a risk of further spinal injuries. (I think this only is applicable in peacetime). -- Per Danielsson pd@sics.se Swedish Institute of Computer Science, PO Box 1263, S-164 28 KISTA, SWEDEN
pt@dciem (Paul Tomblin) (02/07/91)
From: cognos!geovision!pt@dciem (Paul Tomblin) bxr307@csc.anu.edu.au writes: > Most modern, high-speed aircraft now have ejector seats which force >their way through the canopy. This is necessary because at supersonic speeds >there is little time to wait for a canopy to be ejected clear from the aircraft >and then have the seat eject a second later. It was deemed faster to simply >either destroy the canopy or to break through it. American aircraft tend to use the all clear bubble canopies, which in turn leads to having the canopy blown off first, before ejection. This is fine for the clear blue sky ejection, but leads to possibly fatal delays in low altitude flight. It also leads to the possibility of a "Top Gun" style accident, where a plane in a flat spin doesn't leave the canopy behind, and the ejecting person slams into it. Evidently, both the spin and the fatal ejection shown in "Top Gun" are known problems with the F-14. Personally, I'd prefer ejection seats with canopy cutters. (Then again, I'd probably prefer the "Escape Capsule" proposed for the F-111) -- Paul Tomblin, Department of Redundancy Department. ! My employer does The Romanian Orphans Support Group needs your help, ! not stand by my Ask me for details. ! opinions.... pt@geovision.gvc.com or {cognos,uunet}!geovision!pt ! Me neither.
shafer@skipper.dfrf.nasa.gov (Mary Shafer) (02/12/91)
From: Mary Shafer <shafer@skipper.dfrf.nasa.gov>
Paul Tomblin wrote:
Personally, I'd prefer ejection seats with canopy cutters. (Then again,
I'd probably prefer the "Escape Capsule" proposed for the F-111)
No, you wouldn't. Even the Air Force claims that the capsule system
is inadequate and lead to too many injuries. We've been testing some
improved parachutes for the F-111 (dropping capsules from our B-52).
Based on what they've seen in the testing, our pilots recommend _not_
flying in the F-111 (not that I've had any offers, mind you).
(It's not a proposed system--they've had the capsule since the original
prototype flew in the 60s.)
--
Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer
NASA Ames Dryden Flight Research Facility, Edwards, CA
Of course I don't speak for NASA
"A MiG at your six is better than no MiG at all"--Unknown US fighter pilotjabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) (02/13/91)
From: jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) shafer@skipper.dfrf.nasa.gov (Mary Shafer) writes: >From: Mary Shafer <shafer@skipper.dfrf.nasa.gov> >Paul Tomblin wrote: > Personally, I'd prefer ejection seats with canopy cutters. (Then again, > I'd probably prefer the "Escape Capsule" proposed for the F-111) >No, you wouldn't. Even the Air Force claims that the capsule system >is inadequate and lead to too many injuries. We've been testing some >improved parachutes for the F-111 (dropping capsules from our B-52). >Based on what they've seen in the testing, our pilots recommend _not_ >flying in the F-111 (not that I've had any offers, mind you). It's worth pointing out that the B-1A was originally supposed to have a capsule, but problems led to the substitution of conventional ejection seats. I think the main problem was with the capsule's CG being in the wrong place. We've also tried encapsulating the individual seats in the XB-70, but that didn't work well either; when XB-70 #1 went down, the pilot got his elbow caught in the clamshell doors, and the capsule started rolling down a hill after it hit the ground. All in all, I'd rather have a seat. -------- jabishop@uokmax.ecn.uoknor.edu
military@cbnews.att.com (William B. Thacker) (02/15/91)
From: uunet!mcgp1!flak (Dan Flak) In article <1991Feb4.052511.15316@cbnews.att.com> voder!nsc!dtg.nsc.com!alan@decwrl.dec.com (Alan Hepburn) writes: >It seems to me that a canopy designed to withstand >air pressures of supersonic flight would be extremely difficult to >punch through with a slow-moving seat, or head. Does anyone out there >have any real data on this? Can a pilot survive a punch out through >a canopy? In a word -- yes. I've known one pilot who has. To get to the ejection triggers in some type seats, you have to raise the handles protecting the triggers. This is supposed to blow the canopy. When you squeeze the trigger, the seat is supposed to go a quarter of a second later. Hopefully the canopy is gone then. The following is a partial description of my tour in T-33's (high sub-sonic). ----- Sitting in the seat, I noticed several things at once. For starters, my knees were under the instrument panel. I wondered if I would leave them behind in an ejection. We were told that the seat tilted back before ejection, but I wasn't so sure. Secondly, with the seat full down, there was about a half inch between the top of my helmet and the canopy. I had to get used to bending over forward before turning my head around. However, that wasn't the worst of it. The ejection sequence was to raise the handles, and squeeze the triggers. When you raise the handles, the canopy blows. When you squeeze the triggers, the seat goes one quarter of a second later. If the canopy doesn't blow, squeeze the triggers anyway, and a quarter of a second later, the seat will go. For this eventuality, the manufacturer mounted a canopy breaker tool on the back of the seat to knock a hole for the seat to go through. Unfortunately, the tool was located about an inch lower than the top of my head. Nonetheless, people bigger than me have gotten out of the T-33. ----- If you eject under controlled conditions (that is, you have some control over the aircraft -- e.g. you can point the top of the aircraft up), your chances for survival are great. If you have to take what you can get, your chances are diminished. Generally, you want to pull back on the stick to get extra altitude, and lose excess airspeed. Then you want to sit up straight, pull your elbows in, tuck your feet in, and draw your feet and knees together. Then eject. Or, as they used to teach us. "Zoom, Assume, and Boom" -- Would any *sane* person express opinions like this?
andrew@jhereg.osa.com (Andrew C. Esh) (02/20/91)
From: andrew@jhereg.osa.com (Andrew C. Esh) In article <1991Feb15.065658.9396@cbnews.att.com> uunet!mcgp1!flak (Dan Flak) writes: > > [... Writing about T-33 ejection] > >Sitting in the seat, I noticed several things at once. For >starters, my knees were under the instrument panel. I wondered if >I would leave them behind in an ejection. We were told that the >seat tilted back before ejection, but I wasn't so sure. Ejection, as it was explained to me, forces you upward so fast, that your feet fall toward the bottom of the seat, and are not sticking forward to collide with the bottom of the instrument panel. I was told that I should go ahead and TRY to kick the instrument panel on the way out, during ejection training. I never hit it. As far as knees being under the instrument panel, I would guess that that was either a dangerous situation (i.e. you WOULD leave your knees), or the forward edge of the seat pan would either tilt down or was short enough so your knees would trail down the same as your feet. Such an ejection seat design, it would seem to me, would lift you by the harness, instead of the seat of the pants, thereby producing some rather nasty injuries, considering where the straps would bind on you. :-) A seat that tilts back? Maybe one that would slide back would clear the knees, but I have yet to hear of a seat that does any maneuvering before ejection. They spend a lot of time trying to find ways to get the pilot out sooner. Why blow all that by adding a carnival ride prior to ejection? It's easier to design the plane so everything clears. This is also why there are size and weight restrictions on pilots. The part has to fit the machine. -- Andrew C. Esh Open Systems Architects, Inc. (612)525-0000 andrew@osa.com previously: andrew!drum!gong!bangyerdead
henry@zoo.toronto.edu (Henry Spencer) (02/20/91)
From: henry@zoo.toronto.edu (Henry Spencer) >From: jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) >We've also tried encapsulating the individual seats in the XB-70, but that >didn't work well either... In fairness, the XB-70 ejection capsules only got used once, which isn't much of a statistical sample. The B-58 had capsules, which allegedly worked all right. Aircraft intended for sustained supersonic speed really *ought* to have capsules, because bare seats generally are not cleared for use at supersonic speed. (That's right -- all those Mach 2 fighters have to slow to subsonic speeds before ejection or the warranty is void. :-)) -- "Read the OSI protocol specifications? | Henry Spencer @ U of Toronto Zoology I can't even *lift* them!" | henry@zoo.toronto.edu utzoo!henry
urbanf@tuura.UUCP (Urban Fredriksson) (02/23/91)
From: urbanf@tuura.UUCP (Urban Fredriksson) henry@zoo.toronto.edu (Henry Spencer) writes: >In fairness, the XB-70 ejection capsules only got used once, which isn't >(That's right -- all those Mach 2 fighters have >to slow to subsonic speeds before ejection or the warranty is void. :-)) Not _all_. The seat in the J 35 Draken is cleared for supersonic ejection, and has been so for almost 15 years. (They are not the same as in 1959.) It has been stated they are OK up to Mach 1.3. | Urban Fredriksson |"You aren't late for the bus, | I do NOT speak | | Stockholm, Sweden | you are early for the next." | for my employer! |
wcarroll@jake.encore.com (02/23/91)
From: wcarroll@jake.encore.com From jabishop@uokmax.ecn.uoknor.edu (Jonathan A Bishop) > We've also tried encapsulating the individual seats in the XB-70, but that >didn't work well either; when XB-70 #1 went down, the pilot got his elbow >caught in the clamshell doors, and the capsule started rolling down a hill >after it hit the ground. The Dec 90/Jan 91 issue of Air&Space/Smithsonian had a piece on the last flight of XB-70 #1. The REAL interesting part is that the author is Al White, the pilot for that flight. William R. Carroll (Encore Computer Corp., Ft. Lauderdale FL) wcarroll@encore.com uunet!gould!wcarroll "This comment without commentary is not the view of the staff or management of WKPX, the Broward County School Board, ... or even me." - KZ