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Thread: G conditioning

  1. #1

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    G conditioning

    I have found at random times, usually after not flying for a bit, some light headedness when going from +G to -G. does anyone have any condition suggestions to help with the issue?

  2. #2

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    Since no one else has spoken up, I will suggest that the IAC has periodically published articles about the physiology of aerobatics and there is at least one book out there. Fred Lascerda may be the author.

    The human body does not like negative G. Its not built for it. You will note that in the latest Sport Aerobatics Rob Holland notes that you never get to like negative G, you just get used to the discomfort (Rob says this more colorfully).

    My experience is that you just have to fly the figures and build up some famliarity with how you react and some tolerance for the changes. Be advised that you body can only catch up so fast, so we all are, or should be carefull with too much negative followed by an immediate high positive G figure. Going to sleep at the stick is never good.

    To the best of my knowledge, strength training helps with +G tolerance (better anti G straining), but I have never heard of any ground activity that helps with -G.

    So you have another excuse to prioritize flying acro rather than those other distraction activities.

    What category do you fly? Compeition pilots see -G starting at the Intermediate level.

    Fly safe,

    Wes
    N78PS

  3. #3

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    Thanks Wes, I have found some info that may explain a bit. I am fine once establishished with the -g, its more the transition. My normal routine had been to weight train in the morning, while its still cold out, then fly after. I learned ( USAF paper) thats not a good idea. Yesterday I skipped weight training, and just flew. I did several minutes of just transitioning + to - g, with no problems. Of course a sample of one day proves nothing, however, I don't recall having this problem in the summer when I flew before working out. Now that its cold out and preheat anyway, I'll save working out until latter in the day and see what happens.
    I'm not flying compettion as its too time intensive. I just fly for fun trying to maximize what I can do.

    Thanks,
    larry
    Last edited by LJM; 12-17-2011 at 06:55 AM.

  4. #4

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    Big Grin

    Quote Originally Posted by LJM View Post
    I have found at random times, usually after not flying for a bit, some light headedness when going from +G to -G. does anyone have any condition suggestions to help with the issue?
    Larry,

    It is a bit confusing to me that you experience dizziness or grey-out when transitioning from positive to negative G. Generally by my experience it is the transition from negative to positive that causes me to lose some faculties. I have three reasonable guesses about why you experience this.

    First, you mentioned that you used to weight train before flying. While this activity may increase your heart rate it will do two other things: cause you to perspire and more importantly it will isolate a larger volume of your blood in your muscles rather than your head. The loss of water from your blood will thicken it making it harder for your heart to pump it to your head.

    Secondly, during cold weather you body will automatically prevent blood from traveling to extremities to preserve the warmth of the core. That's why your fingers, ears, and toes all turn white and get cold first. Being that more blood is centered in your core, it becomes more difficult to maintain a liberal supply to the brain regardless of your straining technique. A straining technique aims to seal off a quantity of blood toward the head, it cannot effectively push blood back to it.

    Third: Did you consume a meal before hand? Chances are, if you ate anything more than a snack before your flight your blood would have been allocated to the muscles in your stomach to assist in mechanical digestive activities, thus reducing the available supply to your lungs and head. There may also be blood sugar effects at work here too, but that is beyond my comprehension of biology for now. Even after dating a diabetic for a good while, I still don't quite understand that whole mess...and she doesn't either!

    Anyway, my point is that aero-medical factors are constantly at work whenever we fly. Aerobatic pilots should be even more concerned with their influences. I hope this helped in some way. Happy flying to you, sir!!

  5. #5

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    ^^^Good info, thanks!^^^

  6. #6

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    Hi all,

    I must say I noticed that just being generally fit and healthy had a huge impact on my tolerances particularly when I first started out flying a 2160a Robin. After a year or so of flying at least once most weeks I had 3 months off (doing other ratings etc). Came back to it, wondering how I'd cope. At the time, I was quite fit, did alot of running etc. It must have made a difference, as my first aeros in 3 months were my first aeros in a Pitts. The instructor demonstrated two inverted spins, at my request! I was absolutely fine.

    A few years later, I was flying a Yak 52 and at one stage during the 2 years I flew it, I had a few months off, this time no where as fit as I was, and boy I certainly felt it that's for sure.

    cheers,
    Andrew

  7. #7

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    Sounds like an excuse to get a doctor's note prescribing regular absences from your employment for aerobatic therapy.

    Best of luck,

    Wes
    N78PS

  8. #8
    steveinindy's Avatar
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    The human body does not like negative G. Its not built for it. You will note that in the latest Sport Aerobatics Rob Holland notes that you never get to like negative G, you just get used to the discomfort (Rob says this more colorfully).
    That sounds like a fair assessment. There are few things that would make me sell out the US if I had major secrets. Exposure to any substantial negative G would be high on that list. The limited amount of experience I have had with it (thanks to mostly to a ride I managed to get in a centrifuge after agreeing to be a research subject....long story) ranks among the worst experiences I have ever had.
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



  9. #9
    RetroAcro's Avatar
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    Quote Originally Posted by steveinindy View Post
    That sounds like a fair assessment. There are few things that would make me sell out the US if I had major secrets. Exposure to any substantial negative G would be high on that list. The limited amount of experience I have had with it (thanks to mostly to a ride I managed to get in a centrifuge after agreeing to be a research subject....long story) ranks among the worst experiences I have ever had.
    How much -G did you see? Most new aerobatic pilots hate -1G. Then they get used to it and then hate -3G inverted turns. Then they get used to it and don't mind pushing -4 to -5G push ups/outs. You get used to it. Of course in a centrifuge under sustained -G, it would not be much fun even at low -G.

  10. #10
    steveinindy's Avatar
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    How much -G did you see? Most new aerobatic pilots hate -1G. Then they get used to it and then hate -3G inverted turns. Then they get used to it and don't mind pushing -4 to -5G push ups/outs. You get used to it. Of course in a centrifuge under sustained -G, it would not be much fun even at low -G.
    I believe it was -3 or -4 G and it only lasted a few seconds, although it sure as heck seemed like it lasted far longer. They never gave us anything in way of specifics and I wasn't in the mood to ask many questions or really pay much attention. I know another of the subjects (a friend of mine) who suffered hemorrhages into the conjunctiva of one of his eyes as a result of the test run. I count myself as somewhat lucky to have had the experience but still did not appreciate the hellacious headache and nausea that resulted. I have to admit, I actually enjoyed the positive G portion of the run they gave us before the negative G test.
    Last edited by steveinindy; 02-16-2013 at 03:16 AM.
    Unfortunately in science what you believe is irrelevant.

    "I'm an old-fashioned Southern Gentleman. Which means I can be a cast-iron son-of-a-***** when I want to be."- Robert A. Heinlein.



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