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  • G-suits in racing?

    Hi everyone,

    first off I hope I've put this on the correct forum. Tech Talk sounds just right for this, but feel free to move if neccessary.

    Ok, this thread was inspired by a recent post of A.J. in an IndyCar at Talladega.

    I guess we're all familiar with the CART event at TMS in 2001. Drivers (almost) blacking out due to high G-forces.
    Now 5g (or whatever they experienced at TMS) is quite a bit, but it's nothing compared to 8g or even 9g in a modern fighter plane, such as an F-16 or MiG-29. So I started wondering, what do these guys actually do not to black out? It sure isn't all because of a better workout routine, or is it?

    So I did a little research.

    What the drivers at TMS experienced and pilots (and astronauts as well) go through is called G-LOC (G-induced Loss Of Consciousness). What happens physically during a G-LOC is that because of the accelleration a driver's/pilot's blood is literally squeezed into his extremities (mostly into the legs). In return there's no blood (and no oxygen) pumped into the brain, resulting in the driver/pilot just to black out.
    That's why the fighter pilots have so called g-suits. A G-suit has like internal airbags which are inflated at a certain G-force. These airbags squeeze the legs so tight that the blood simply can't go there anymore and has to stay in the upper part of the body.
    A link with better explaination: http://en.wikipedia.org/wiki/G-suit

    My question to the tech-guys here is, whether such G-suits would actually make any sense in racing? Or would there be complications?

    Thanks in advance for your replies.


    ~Capt. Nutella

  • #2
    Tactical aircraft and race cars are different animals in the G world. The G LOC is caused in aircraft because the pilot sits upright and the pull of gravity in high G turns is from head down to the toes, where the blood pools in the lower extremities. In race cars the driver is in almost the perfect position to handle G's with the head very close to the heart level and the G loads are sideways not head to toe.

    CART didn't want to run Texas, it was an excuse. Drivers in their cockpits have their heads restrained sidewards by pads and HANS devices helping fight the centripetal force of the turn. If the driver experiences anything it would be a vestibular sensation (middle ear) which can cause dizzyness. It is not a "G" force thing.
    "Life's journey is not to arrive at the grave safely in a well preserved
    body, but rather to skid in sideways, totally worn out, shouting
    "...holy $^!+...what a ride!"
    >

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    • #3
      Originally posted by Niseguy
      Tactical aircraft and race cars are different animals in the G world. The G LOC is caused in aircraft because the pilot sits upright and the pull of gravity in high G turns is from head down to the toes, where the blood pools in the lower extremities. In race cars the driver is in almost the perfect position to handle G's with the head very close to the heart level and the G loads are sideways not head to toe.

      CART didn't want to run Texas, it was an excuse. Drivers in their cockpits have their heads restrained sidewards by pads and HANS devices helping fight the centripetal force of the turn. If the driver experiences anything it would be a vestibular sensation (middle ear) which can cause dizzyness. It is not a "G" force thing.
      Two things, one the more vertical seating of the CART cars makes them slightly more susceptible to G's.

      Here is a comparison of the relative Lateral G's at various corner speeds at TMS.

      Turn Spd Comp G-Force
      205 3.77
      210 3.96
      215 4.15 IRL Race 2004
      216.4 4.20 IRL Race 2005
      220 4.34
      222 4.42
      224 4.50 IRL Race 2003
      226 4.58
      228 4.67 Highest CART G in Qual 2001
      230 4.75
      231 4.79 Highest CART G in practice, 2001


      rh
      That old possum lost the fight, His sad, black eyes; what a thing to see on a glowing Easter Sunday
      @Hoop98

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      • #4
        Lateral Gs aren't really a problem, but the thing is at Texas they only had the 1/4 mile back straight (at 240 mph a whopping four seconds) not loaded laterally or vertically.

        Running Texas for G-loading would be similar but not quite as bad as for example, running Talladega. As well, at Talladega the drivers have more recovery time.
        "I kill for the code to disarm this mess..."

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        • #5
          Originally posted by Marc P. Gregoire
          Lateral Gs aren't really a problem, but the thing is at Texas they only had the 1/4 mile back straight (at 240 mph a whopping four seconds) not loaded laterally or vertically.

          Running Texas for G-loading would be similar but not quite as bad as for example, running Talladega. As well, at Talladega the drivers have more recovery time.
          Those numbers are the vector sum, they were about 2.5 vertical and 4 Lateral if I remember correctly, will look it up but yes the G Duty cycle was the issue.

          I think the CART guys would have been fine because at that time there was a large drop off from qualifying to race laps, but I also believe the fault was in lack of testing, IMHO...

          it was not unreasonable to take the steps they did.

          BTW I used IRL/NASCAR speeds for the G analysis, if you believed CART segment measurements the cars dove into the corner, cranked left wheel in, started incurring cornering drag and magically sped up. That's because they measured the segment distance out by the wall, not in the groove.


          You must always choose time rather than speed to compare the 2.


          rh
          That old possum lost the fight, His sad, black eyes; what a thing to see on a glowing Easter Sunday
          @Hoop98

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          • #6
            Originally posted by hoop-98
            Those numbers are the vector sum, they were about 2.5 vertical and 4 Lateral if I remember correctly, will look it up but yes the G Duty cycle was the issue. You must always choose time rather than speed to compare the 2.
            I did the math for cornering speeds at Texas of 225 mph and 235 mph at Talladega and got a vertical G load for both of approximately 2.1 gs.

            Talladega is steeper banking but a greater radius with much longer straights between, Texas is more shallow banking but a much tighter radius with shorter straights. I think that was the real issues is that the drivers were facing significant loading for all but four or five seconds a lap.

            An interesting point is that if you measure Talladega three feet above the white line rather than 15 feet inside of the outside wall (NASCAR's method), Talladega and IMS are both 2.5 miles.

            IRL uses a method based on computing the average racing line for track distance outside of IMS, CART was using the outside edge plus the inside edge divided by 2 to get their track lengths at the time, IIRC. When they re-measured like that, Milwaukee grew to over a mile and Nazareth shrunk to 19/20 of a mile.
            "I kill for the code to disarm this mess..."

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            • #7
              CART didn't want to run Texas, it was an excuse. Drivers in their cockpits have their heads restrained sidewards by pads and HANS devices helping fight the centripetal force of the turn. If the driver experiences anything it would be a vestibular sensation (middle ear) which can cause dizzyness. It is not a "G" force thing.
              Sorry, but you do not know of what you speak. Neither the head pads nor the HANS make any difference on the g's experienced by the driver or any G-LOC effects. It's blood flow (or lack thereof) that causes G-LOC effects and neither a head pad nor HANS does anything to affect blood flow.
              BAN SHREDDED CHEESE! MAKE AMERICA GRATE AGAIN!

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              • #8
                Yes! definitely g-suits! adding several hundred thousand dollars worth of required driver safety gear to an already financially floundering sport would be a great move.... Maybe, they could lease them for a million a year! It works for Honda............... Actually a far better solution would be to find tougher drivers
                .

                http://indyroadsters.webs.com/
                http://macmillersgarage.webs.com/
                http://www.youtube.com/user/macmiller46241


                I love any race car whose last name is "Special"

                .

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                • #9
                  Jakester,
                  Let me say, I ran the human flight experiments at NASA for 18 months, flew off of aircraft carriers for 18 years, and have flight tested systems for tactical aircraft for the Navy and Air Force. The problem is vestibular, not G LOC.

                  Your theory would have pilots dying on a Cat shot where you get 12 transverse G's. (Transverse is the perfect way to experience G's by the way)
                  "Life's journey is not to arrive at the grave safely in a well preserved
                  body, but rather to skid in sideways, totally worn out, shouting
                  "...holy $^!+...what a ride!"
                  >

                  Comment


                  • #10
                    Boy this thread conjures up wicked thoughts...

                    Just imagine how much wider Foyt would have had to make his last March chassis to accommodate the G-suit!

                    ZOOOM
                    "Doc, just set them fingers sose I can hold the wheel"
                    James Hurtubise, June, 1964

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