aerospace

Discussion in 'Architecture & Engineering' started by PieAreSquared, Feb 1, 2010.

Thread Status:
Not open for further replies.
  1. jonte92 Registered Senior Member

    Messages:
    31
    do you know what sollust, this is not really the limit all we need to do is to design a G suit with better capabilities than those that we have today. take for example, if computers are getting better day by day, then why aint aviation getting better, does it mean that aviation is at the limit o f its creativity, i hope not!!
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. soullust Registered Senior Member

    Messages:
    1,380

    It is possible, but G-suits work by applying pressure to the pilots, and the best suits today all ready have reached the limit of the amount of pressure that can be applied to the Human body, But they may be able to build some form of counter measure beside the actually g-suit ???

    Only time will tell.
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,510
    And it's still in trouble. Technically and financially.

    Strangely (and more or less counter-intuitively) the safety of twin-engined jets (fighters) isn't statistically significantly better than that of single-engined types.

    What? What exactly is the "speed limit" for manned aircraft?
    And why is it a limit?
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. soullust Registered Senior Member

    Messages:
    1,380
    oh dude the exact speed... I will find that answer out for you but I do not have that off the top of my head, But later when i have a bit more time i will get that for you.But it is Its limit because the Vertical G-force on the pilots is at the point where basically, if there was a failure in the pilots g-suite, he would black out or at least Grey out in seconds.

    And also, You black out because g-force, is at the point that it apply pressure on your The pilots spine, and changes his blood pressure, It could be lower or the blood is forced to your feet, (G-suits help prevent this by applying continued pressure on the pilots feet.) but anyway, This would cause a blackout, Where the pilot is conscious,but he is blind.

    then there is red-out, to much blood to the brain, your site is reddening.
    then you get a G-loc total unconsciousness, after that you get death.(death can occur at i believe 16-g or 17... in less then a minute.
     
    Last edited: May 6, 2010
  8. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,510
    No.
    Speed by itself doesn't cause G-forces. Only manoeuvre at speed. (And if the manoeuvre is done correctly then it's possible at any speed).
    For example, do you consider Mach 3 to be the limit? (Blackbird). Or Mach 6.7? (X-15). How about letting the USAF know because they're working on Mach 12-15 manned aircraft.

    IIRC it was Canada (and the USN) that actually sparked the study of twin- versus single-engine types safety records.

    No, the blackout is caused because blood is drained out of the brain.

    Legs and lower abdomen (especially the upper legs where major blood vessels are located), not feet. Take another look at a G-suit - it doesn't cover the feet.

    Which is caused by negative G. And it's blood to the eyes - it can cause retinal damage.

    16-17 G? Really?
    http://forum.ebaumsworld.com/showthread.php?t=73659
    http://www.extremefunnypictures.com/funnypic565.htm
     
    Last edited: May 6, 2010
  9. soullust Registered Senior Member

    Messages:
    1,380
    The best you can get out of maneuvering is a positive G-force, again the blood going from your brain (and everywhere in between) to your feet.

    Now a negative g-force is your the blood rushing from the feet (and everywhere in between) to your brain.

    There is No maneuvering that can get any better then positive g-force.(which is more tolerable then a negative g-force.

    there is no stooping G-force in any way during high speed dog fights.

    Now as for a simple description of how G-force works. were sitting here at our computers and were at 1G, now a modern aircraft is capable of pulling lets say 9 G's with out any effort. But the problem with that is if you pull 9 G's our weight increases correspondingly, so your 10 pound head will weigh 90 pounds.

    Now if you Continue to pull such high G's , the G-force will push the blood from your body to your feet, over coming the attempts of your heart to pump the blood back to your brain.

    Now negative g-s are much worse then positive.so we avoid these, if at all possible.

    an easy way to do this is roll the air craft 180 degrees, and pull back on the stick.if you roll in a way that your cockpit is still facing the ground, and again pull back you will still be diving but will be experiencing positive g-force.


    "Human tolerances depend on the magnitude of the g-force, the length of time it is applied, the direction it acts, the location of application, and the posture of the body.

    The human body is flexible and deformable, particularly the softer tissues. A hard slap on the face may briefly impose hundreds of g locally but not produce any real damage; a constant 16 g for a minute, however, may be deadly. When vibration is experienced, relatively low peak g levels can be severely damaging if they are at the resonance frequency of organs and connective tissues.

    To some degree, g-tolerance can be trainable, and there is also considerable variation in innate ability between individuals. In addition, some illnesses, particularly cardiovascular problems, reduce g-tolerance."

    And yes Humans can survive, brief exposer to 100> G's In a car accident.

    My argument is based on Vertical axis g-force


    http://g-force.software.informer.com/wiki/
    http://www.jet-fighter-rides.com/tag/g-force/

    http://www.youtube.com/watch?v=Sd_zDafdKQI
    http://www.youtube.com/watch?v=bW2zqJJQ9Z4

    Oh and as for the pressure on the feet i just wasn't getting very technical and just referring to the bottom half of the body.the thread is not really based on that.

    And a fighter jet doing Mach-12 to Mach 15...I call bull shit, on that one.

    Prove it.
     
    Last edited: May 6, 2010
  10. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,510
    What do you mean "best"?
    Manoeuvre can also create negative G.

    Again, what do you mean by "better"? Ideally, for the sake of the pilot (and airframe life) it's better to not induce any G.

    Stooping? If you mean stopping then of course there is: reduce speed or increase the radius of turn.

    Have you ever heard the phrase "teaching your grandmother to suck eggs"? I have ~50 years of reading about, learning and analysing air combat.

    Some confusion here. The G-force isn't induced by the dive itself.

    You mean, as in downwards through the pilot's body? Such as happens when he ejects?
    http://www.ejectionsite.com/ejectfaq.htm#5

    Which gives you some idea of the limited depth and breadth of your aerospace knowledge...

    Please Register or Log in to view the hidden image!


    I didn't say "fighter" I said manned aircraft - it's planned to be a fast-reaction bomber.

    Airforce and NASA Works With UB to Develop a Future Hypersonic Aircraft
    High Speed/Hypersonic Aircraft Propulsion Technology Development
    SHAAFT
    And there was an extensive (3-part) article in Air International some years back by Dr David Baker on USAF plans for hypersonic combat aircraft.
     
    Last edited: May 6, 2010
  11. soullust Registered Senior Member

    Messages:
    1,380
    Yes but all along i was referring to jet fighters

    Please Register or Log in to view the hidden image!




    And i know you know your stuff, But i posted a bit more there just so other people can get an idea of what it is,

    I didn't in no way intend to offend you sir

    Please Register or Log in to view the hidden image!



    And yes you are correct, it has allot to do with the speed as well as the dive.

    But the dive is what decides whether you're experiencing Positive-g or negative-g..Basically on any high speed maneuver it is best to go head first into the sharp dive which will produce positive Gravity force.

    If you just dive straight down or into the dive the pressure will be Negative
    G's

    You want to keep the G-force pushing to wards your head as much as possible.

    Aw Very nice, and yes i can see bombers going much faster then even 15-G's. In the next few years.

    But G-force for the Time being will Limit the speed Of fighters, But that does not mean they won't get stealthy(ER) lighter and carry a much larger payload in the future.

    Your Job is at a computer isn't it?

    If so isn't it great how forums pass time,

    Sorry for the spaces my key board is being a pain.
     
    Last edited: May 6, 2010
  12. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,510
    The topic is aerospace and I did write "manned aircraft". On the other hand the Blackbird was originally planned with a missile-armed interceptor (Mach 3+) variant and the F-108 and rival were supposed to do Mach ~4. Plus later developments of the CF-105 Arrow were intended to be even faster.

    No, the method of getting into the dive determines it. A nose-over is negative G, a half roll and stick back is positive G.

    Pushing towards your head? That's negative G. Either way pilots (and aircraft designers) would rather have as little G as possible: pilots because it has an effect on them (not just G-LOC/ redout or whatever but haemorrhoids as well!) and designers because making the structure tough enough to withstand extra G uses weight and material they'd rather not put there.

    What do you mean "for the time being"? You don't think Spitfires/ Me 109s etc pulled 9G?
    The only difference these days is that modern fighters can sustain 9G.

    Job? What's a job?

    Please Register or Log in to view the hidden image!


    Besides, it's 3 in the morning for me...
     
  13. soullust Registered Senior Member

    Messages:
    1,380
    External force pushed Towards your head from the top will push the blood out of the head towards the feet.

    But GRRRR you know what i mean

    Please Register or Log in to view the hidden image!





    It's not the point of weather any jet can hit them, The problem is how long they can hold them.



    3 am, where do you live ? it is only 11:30 here..
     
  14. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,510
    How long do you need to hold 9G? If you're in a constant 9G turn you're a sitting duck anyway: never maintain one direction or attitude (I know turning isn't strictly speaking maintaining a direction, but it is predictable if you're going in circles where you'll be in the next couple of seconds...)

    UK.
     
  15. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

    Messages:
    7,406
    Your language seems to indicate a rather naive understanding of what is going on.
    Do you know what "positive G" and "negative G" actually refer to?

    And they don't produce "Gravity force".
    Gravity does what it does - and last time I looked it's dependent upon mass, not speed / velocity.
    You seem to be confusing "G" (or "g") with "gravity". Earth gravity is "1g" (or roughly 9.81 m/s^2)

    Ideally you want no G whatsoever... would be much better.

    Really? I can't.
    You now seem to be confusing "G" with "mach". G-force is an acceleration. "Mach" is a speed / velocity.
    And even bombers going Mach-15... no - not in the next few years.
    Unless you're referring to intercontinental ballistic missiles as "bombers"?

    SSTO space-planes may end up at that speed, though.

    Perhaps longer term the military might utilise mach-15 vehicles, but why bother when you could just improve missile targetting techniques and launch missiles.

    Please Register or Log in to view the hidden image!


    What determines the speed of your car? Is it g-force, manoeuvrability, or the engine power/weight ratio? Clue: it's not the G-force.
    G-force is nothing but a resultant force experienced by the pilot/aircraft from the changes in velocity it is capable of through its aerodynamic design and engine etc.
    The limiting factor to speed will be the engine and weight of the aircraft.
    The limiting factor of high-velocity manoeuvrability will be the pilot/aircraft design and the G that they are capable of withstanding - not the g-force itself. The g-force will be whatever it is when an aircraft pulls a manoeuvre.

    Remove pilot and you open up design to higher-g manoeuvres.
     
  16. soullust Registered Senior Member

    Messages:
    1,380
    it was me wording it, in a way that was simplified, and you will never get no g-force, the laws of physics, stat that.
     
  17. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,510
    Ideally you want no G force. After that you want as little as possible.
    On the other hand "you will never get no g-force, the laws of physics, stat that" is untrue.
    Ever heard of "unloading"? The pilot puts the aircraft into a shallow dive and goes into free fall - zero-G. Straight from the laws of physics.

    Please Register or Log in to view the hidden image!

     
  18. jonte92 Registered Senior Member

    Messages:
    31
     
  19. soullust Registered Senior Member

    Messages:
    1,380
    Yeah, but i think a jet in a free fall = eject

    Please Register or Log in to view the hidden image!

     
  20. kmguru Staff Member

    Messages:
    11,757
    Soon manned combat planes will be obsolete.
     
  21. Omega133 Aus der Dunkelheit Valued Senior Member

    Messages:
    6,281
    Not so. Humans have judgement, instinct, experience. A computer doesn't have any of that. Computer's are good for surveillance, but i'm not sure i'd trust them for combat roles.
     
  22. draqon Banned Banned

    Messages:
    35,006
    Why hasnt moderator deleted the irrelevant to subject on T-50 picture? The O.P's picture is that of the crappy costly F-22. Please use relevant picture.
     
  23. draqon Banned Banned

    Messages:
    35,006
    unmanned planes need people too. And even automated unmanned planes need people, for maintainance. And even if you will have automated maintainance for automated unmanned planes, who will maintain the maintainance? Sooner or later you need people in there.

    http://www.youtube.com/watch?v=RYnYEl4di94&feature=related

    (of course the above video is american military superiority propaganda, but neverthless americans along with their buddies from israel made extreme technological advances in UAV research)
     
Thread Status:
Not open for further replies.

Share This Page