Announcement

Collapse
No announcement yet.

More F-22 problems

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Originally posted by Jimmy View Post
    There are probably multiple problems. One is hypoxia. That's an issue that a pressure suit could fix, but pilots are experiencing it even at lower altitudes. When you're hypoxic, it takes almost zero time to snap back to reality once you start getting air. The pilot that died in Alaska was hypoxic until impact, and he was certainly low enough that altitude wasn't the issue. The other problem is that there are chemicals making their way into the pilots' bloodstreams. They're getting [i]something[i] into their lungs that's coming from somewhere, and it's not just the charcoal. Maybe there's a common link between these problems, I have no idea. But these are two separate effects that may or may not be related.
    Could it be that the pilot in the crash didn't experience hypoxia but something more akin to CO poisoning? Maybe a common source of carbon contaminants is causing a variety of carbon species to get into pilots' lungs....

    Comment


    • #17
      Originally posted by Jimmy View Post
      None of that explains anything. The SR-71 used a completely different type of life support system than the F-22...they have nothing in common. The pilots will spend most of their time on the mask, while the maintainers are breathing what should be ambient air when they're in the cockpit. Completely different sources of air. If the problem was something from the cockpit itself, there's no way it should get into the pilot's mask, or vice versa.
      “The Air Force experts trying to figure out the cause of the problem have pointed out that the F-22 flies higher and faster than its predecessors, the F-15 and F-16 “.I was referring to this statement when mentioning the SR-71.

      What is common with the mechanics and the pilots whom got ill? Toxins can be absorbed also trough the skin not just trough breathing. The pilot is in the cockpit,breathing the air trough the life support system while the mechanics are on the ground but in the hangar doing maintenance which is also an enclosed area but on the different scale. They both got sick while working in the cockpit so the element that is doing the contamination is heavy and stays in the cockpit. So the only chemical that can be in the cockpit that might be interacting is the paint,like standing close to the open can of car paint or something. You need to be close to it in order to affect you. Since almost all paints are made out of polymers that decompose due to the UV radiation and F-22 flies high where the UV radiation is higher and F-22 canopy is big and clean, it exposes the paint in the cockpit to UV radiation thus making it change its composition and affecting both pilots and the ground crew. Also plastic and other composites might be affected by the UV radiation. And Alaska is close to polar circle and we all know that there is an ozone hole there so the UV radiation higher too.

      I mean, I don't know, I am not an expert on these things just guessing taking the Murphy’s law into the account combined with the Occam's razor, if you have the super complicated system such as the F-22's is, the problems that affect the pilots are usually simple and hidden in the plain sight. Thus the paint theory comes.

      Comment


      • #18
        Originally posted by citanon View Post
        Could it be that the pilot in the crash didn't experience hypoxia but something more akin to CO poisoning? Maybe a common source of carbon contaminants is causing a variety of carbon species to get into pilots' lungs....
        I'd bet on something like this...

        Comment


        • #19
          I think, maybe about half of the "known" cases are due to a psychological effect. After all those highly publicized scary stories, the pilots and maintenance workers are just too afraid and, perhaps, some of them take their fantasies as a reality.
          Maybe the hypoxia of the ground workers is a completely psychological issue.

          Comment


          • #20
            Originally posted by Skywatcher View Post
            Maybe that's why the DoD has been so adamant about capping F-22A buys at 187, despite the F-35's problems.
            The cap came down years before any O2 problems were noticed.

            Originally posted by citanon View Post
            Could it be that the pilot in the crash didn't experience hypoxia but something more akin to CO poisoning? Maybe a common source of carbon contaminants is causing a variety of carbon species to get into pilots' lungs....
            I have no experience with CO poisoning, but the final few moments of that flight sure sound like hypoxia to me. Maybe the symptoms are similar though.

            I don't the F-22's life support system, and we're not likely to guess the reasons. The AF and LockMart took these things apart for 5 months and couldn't figure it out, it's probably not an easy solution.
            Last edited by Jimmy; 12 May 12,, 15:46.

            Comment


            • #21
              This blows my mind. Replace the damned OBOGS with a bottle. We've had O2 bottles since WW1. They work.

              Pilot gets symptoms of ANY kind, switch to 100% O2. Nothing enters the pilot's lungs except guaranteed dry pure oxygen, of the sort that tens of thousands of aviators have relied upon for decades.

              Problem solved. LM and the USAF can mail me a check.

              Comment


              • #22
                Originally posted by jlvfr View Post
                But when the plane endangers people while still on the ground...

                Mystery of F-22 illnesses grows
                we always had news that F22 is for strategic deterrance only. as, if the same US can't develop their new F35 properly then how can we think that their old 5th gen might not have the same problem as the F35 has? it is believed that F22 is a true stealth aircraft which can be used to special missions but it can't be used for combat dog fight like forward 4++ aircrafts. read the news as below. how can we think that US might have any success in F22 developments in 90s while they can't complete their new 5th gen projects, F35/ JSF? both are the same type of aircrafts but F22 is double engine like PAK FA/ J20 and F35 is single engined? its good that US has kept its F22 project hidden otherwise other could get more chance laugh on them ..................

                Part of the presentation showed a computer simulation which calculated that the F-35 would be consistently defeated by the Russian-made SU-35 fighter aircraft. The defeat calculated by the scenario also showed the loss of the F-35's supporting airborne-early warning and air-to-air refueling aircraft.

                Independent air combat analysts from Air Power Australia have also stated that the F-35 is not capable of facing high end threats; that what will be delivered (if it ever arrives) will be obsolete; and that the F-35 is not affordable or sustainable.

                http://www.f-16.net/news_article4416.html

                Comment


                • #23
                  Originally posted by Chogy View Post
                  This blows my mind. Replace the damned OBOGS with a bottle. We've had O2 bottles since WW1. They work.

                  Pilot gets symptoms of ANY kind, switch to 100% O2. Nothing enters the pilot's lungs except guaranteed dry pure oxygen, of the sort that tens of thousands of aviators have relied upon for decades.

                  Problem solved. LM and the USAF can mail me a check.
                  IIRC, pure oxygen are perfect breeding grounds for bacteria and can accelerate bacteria's growth by a couple factors.

                  Comment


                  • #24
                    Originally posted by Blademaster View Post
                    IIRC, pure oxygen are perfect breeding grounds for bacteria and can accelerate bacteria's growth by a couple factors.
                    There's a switch to go to 100% or ambient mix. You leave it on "normal" until there's a reason.

                    The point of OBOGS was to eliminate all the support necessary. The LOX infrastructure is significant...eliminating it would free up a lot of maintainers and get rid of a lot of dangerous equipment from the backshops and flightline. I don't know what's different about the F-22's OBOGS...Harriers have been using one since the 70s.

                    Comment


                    • #25
                      Originally posted by Jimmy View Post
                      There's a switch to go to 100% or ambient mix. You leave it on "normal" until there's a reason.

                      The point of OBOGS was to eliminate all the support necessary. The LOX infrastructure is significant...eliminating it would free up a lot of maintainers and get rid of a lot of dangerous equipment from the backshops and flightline. I don't know what's different about the F-22's OBOGS...Harriers have been using one since the 70s.
                      Do they use the same fuel?

                      Comment


                      • #26
                        Doesn't have to be LOX. I would wager good $$ that if the OBOGS was removed, the void remaining would accept a huge conventional O2 bottle. I understand there would be more maintenance, but it would not be of a particularly high tech or challenging nature. Wheel out the aviator's O2 cart, plug in, top off.

                        Normal operation is pressurized cockpit. There might be a small amount of O2 used to enrich the mix, but not all that much. If the system loses cockpit pressure, the diluter-demand regulator system recognizes this, and the switch to higher percentages of O2 is automatic. At around 33,000', it will deliver 100% O2. Above that, it'll start to pressurize the mask, pressure-breathing, which is unpleasant for the pilot, but loss of cabin pressurization would be an emergency calling for a descent ASAP. Unless the rules have changed, the USAF does not allow unpressurized operation above 25,000' with some very rare exceptions. Combat or emergencies is obviously one of them.

                        Comment


                        • #27
                          Originally posted by Versus View Post
                          “The Air Force experts trying to figure out the cause of the problem have pointed out that the F-22 flies higher and faster than its predecessors, the F-15 and F-16 “
                          Doesn't the F-15 have a particularly high top speed of around Mach 2.5? Raptors are flying faster than that?
                          Leaving aside the SR-71, which was a marvel of engineering, the old Mig-25s used to fly at extremely high altitudes as well. Never heard of hypoxia cases in Mig-25 pilots. Although I don't know if the 25 pilots also used full body pressure suits.
                          It is unlikely that the speed or altitude has anything to do with this. More likely a glitch in the OBOGS along with the Bermuda Triangle effect - attributing unrelated incidents to the same unknown cause.
                          Last edited by Firestorm; 15 May 12,, 01:12.

                          Comment


                          • #28
                            Originally posted by Firestorm View Post
                            Doesn't the F-15 have a particularly high top speed of around Mach 2.5? Raptors are flying faster than that?
                            I'm sure Jimmy and/or Chogy could be more eloquent than me but, yes, the F-15 DOES have a top speed of around M2.5. However, as Jimmy pointed out in an earlier post, he himself has only exceeded M2 a handful of times. The problem with going that fast is it burns A LOT of fuel (probably about four times as much fuel as cruising at M 0.9, which is where the Eagle spends most of it's time).

                            I think what they meant by "higher and faster" is that the F-22 is very comfortable at 60K+ (it's absolute ceiling is still classified, but it's probably up around 75K), and can supercruise at M1+, whereas the Eagle is (somewhat) struggling at 60K (though it CAN go a lot higher than this simply on the thrust of it's engines), and anything over M1 for the Eagle requires the use of afterburners (which burns more fuel).

                            Raptors are CAPABLE of M2+, but the problem isn't thrust (it's got about 33% more thrust than the Eagle), it's aerodynamic heating from skin friction, and it's fixed (non-variable) inlet structure; the polymer materials that cover the Raptor don't really like temperatures any higher than 2-300C, and the fixed inlets limit it's efficiency at anything above M2. It'll supercruise all day at M1.5-1.6, but anything over M2 for the Raptor will be a struggle.
                            "There is never enough time to do or say all the things that we would wish. The thing is to try to do as much as you can in the time that you have. Remember Scrooge, time is short, and suddenly, you're not there any more." -Ghost of Christmas Present, Scrooge

                            Comment


                            • #29
                              I've never seen M2. I have been supersonic in an F-15 once, but that was only for a few seconds and it was nowhere near that fast. My normal jet flies about .6-something.

                              But typically cruising speed is not supersonic, fuel is consumed way too fast to make that viable, plus it's illegal over most of the country because sonic booms cause damage. There was hell to pay when an F-16 out of Hill broke the sound barrier near the base (pretty populated area). The boom hit, then bounced off the mountains and came back again.

                              Comment


                              • #30
                                And I'll bet Jimmie doesn't ever want to go M1 while in his normal plane

                                Comment

                                Working...
                                X