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  • A few thoughts...

    Dear AAFO and Jimmy fans

    I watched with mixed emotions last night as the NTSB thread descended into name calling and personal challenges.

    This may not be appreciated by the ownership of this site, and as such they have the right to remove this thread also, but I feel it appropriate to point out some facts and simple aerodynamic truths

    Fact, Ghost had a fixed right trim tab and electronically controlled and re-rigged left tab

    Fact, the NTSB reviewed all imagery and telemetric data and found evidence that Jimmy had to impart opposite control forces to counter-act the left roll moment induced on the aircraft 'throughout' the race

    Fact, at the time of incident, the a/c was subjected to a near instantaneous 17G load, followed by a continuous right roll and descent.

    Several people questioned the 'buried in right quadrant' comment on the other thread. Frankly, that is a rather conservative statement. Let's look at it from a factual basis using the 2nd and 3rd items above.

    Jimmy DID have to keep steady right/down pressure on the stick during level flight and this would have increased exponentially in turns and as speed increased. The sudden high-g pitch up and the continuous right roll prove that the forces on the a/c were extreme. Further, if one looks at the imagery as the a/c rolled inverted it is clearly evident that Jimmy was pinned down & right in the cockpit, further supporting the claim. Gravity never lies.

    For the laymen out there, here's an illustration of the above in action:

    1) Get in you car and at 20mph, induce a left skid and note the control input necessary to correct

    2) Repeat the process at 100mph, on a wet road, in the face of a 40knot quartering wind. Now note just how much effort is needed to correct.

    See the point?

    As to the comment that 'all a/c need opposite input and it is the skill of the pilots that makes it all ok' (paraphrased), this is somewhat correct but also an apples/oranges comparison. Yes, any a/c which hits wake turbulence or experiences a mechanical failure of an aero surface will require counter-acting force to re-balance the a/c. However, no properly set up a/c EVER requires continuous opposite input of the degree shown in this case simply to maintain its course.

    So, in conclusion... the comments by King et.al. were not only valid, but also based on scientific fact

  • #2
    Re: A few thoughts...

    Without stirring controversy, I do need to ask a greater question to the people participating in the discussion of the deleted thread and compare their argument versus experience.

    Of the people who were arguing on either side of the discussion....

    1. How many are actual pilots who understand what it takes with the simple aspect of just flying an airplane, how aerodynamic forces work, controls respond, and the simple basics?

    2. How many are actual pilots who have flown a high performance airplane?

    3. How many are actual RACE pilots who have flown a RACE plane at RACE speeds around a course, and know what the control functions look and feel like at various trim settings?

    4. How many are structural or aerodynamic engineers who 'know what they are talking about'?

    5. How many have actually participated in an accident investigation and understand not only what goes into it, but more important what does NOT go into it or taken into consideration (i.e. personal bias against the pilot)?

    6. How many are just race fans who feel passionate about it, but just don't like what they are reading because it hits close to home?

    I'd be interested to see where everyone falls along a bell curve. But I'm sure it would put things in perspective and show that it's mostly just fans who feel passionate about it and don't want to see one of their heroes proved to be just another human who made mistakes regardless of how great of a guy he was.

    I've said this before...as hard as this whole topic is to digest, it is a learning experience to everyone, and quite honestly, if we all WEREN'T so passionate about it, nobody would be making a big deal out of it.

    Comment


    • #3
      Re: A few thoughts...

      Originally posted by al baby View Post

      Fact, Ghost had a fixed right trim tab and electronically controlled and re-rigged left tab
      Left tab unit was stock in the horizontal and elevator, but not re-rigged. It was the only one connected but was all the stock components in the mechanism with the exception of the tab its self. That was made of alum and was not stock. Stock was phenolic material. As you noted how pilot inputed change was a modification from a manual knob in the cockpit to the electric motor with a switch in the cockpit.
      Originally posted by al baby View Post
      Fact, the NTSB reviewed all imagery and telemetric data and found evidence that Jimmy had to impart opposite control forces to counter-act the left roll moment induced on the aircraft 'throughout' the race

      Fact, at the time of incident, the a/c was subjected to a near instantaneous 17G load, followed by a continuous right roll and descent.

      Several people questioned the 'buried in right quadrant' comment on the other thread. Frankly, that is a rather conservative statement. Let's look at it from a factual basis using the 2nd and 3rd items above.

      Jimmy DID have to keep steady right/down pressure on the stick during level flight and this would have increased exponentially in turns and as speed increased. The sudden high-g pitch up and the continuous right roll prove that the forces on the a/c were extreme. Further, if one looks at the imagery as the a/c rolled inverted it is clearly evident that Jimmy was pinned down & right in the cockpit, further supporting the claim. Gravity never lies.

      For the laymen out there, here's an illustration of the above in action:

      1) Get in you car and at 20mph, induce a left skid and note the control input necessary to correct

      2) Repeat the process at 100mph, on a wet road, in the face of a 40knot quartering wind. Now note just how much effort is needed to correct.

      See the point?

      As to the comment that 'all a/c need opposite input and it is the skill of the pilots that makes it all ok' (paraphrased), this is somewhat correct but also an apples/oranges comparison. Yes, any a/c which hits wake turbulence or experiences a mechanical failure of an aero surface will require counter-acting force to re-balance the a/c. However, no properly set up a/c EVER requires continuous opposite input of the degree shown in this case simply to maintain its course.

      So, in conclusion... the comments by King et.al. were not only valid, but also based on scientific fact
      A trim system in an aircraft induces control inputs at the direction of the pilot to lessen loads the pilot has to deal with with what his hands or feet are on. The control positions on the wing and tail were not centered but it doesn't mean the pilot was fighting the controls if the trim was used to position them. ie aircraft wants to climb and you have to push forward with constant pressure on the stick, if you trim nose down, the trim tab goes up, the elevator goes down as well as the nose of the A/C. The force the pilot is pushing on the stick is reduced or goes away.
      Originally posted by al baby View Post
      Jimmy DID have to keep steady right/down pressure on the stick during level flight and this would have increased exponentially in turns and as speed increased.
      In a turn you have to change the input loads on the control stick or possible only reduce loads depending on trim or stick pressure. Your statement infers to me that you are increasing the right/down pressure in a turn when it could be the opposite as the turns are to the Left. If you are holding right pressure on the ailerons straight and level to turn left you must roll to the left by reducing your current pressure you are holding to the right or go so far as to move the stick to the left. The elevator has to raise the nose so back pressure needs to be inputted to the stick or at least a reduction in forward pressure. It could have been set to trim in a left turn so all he had to do was release the R/H pressure in the turns and input it during the straights.
      Originally posted by al baby View Post
      The sudden high-g pitch up and the continuous right roll prove that the forces on the a/c were extreme
      The pitch up appears to occur when the fixed elevator tab on the right side broke loose and forced that elevator up. It was un commanded by the pilot it appears. Possibly both elevators were no longer attached to their controls at that point where they broke loose so further pilot input of pitch control could not have been made. L/H elevator had sheared rivets that attach the elevator to the tube, R/H tube was fractured around the circumference at the rivets.
      Last edited by 51fixer; 08-31-2012, 10:02 AM.

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      • #4
        Re: A few thoughts...

        Well stated Jim. Enough said. Lets get on with Reno 2012. Wayne you are doing the right thing.
        Lockheed Bob

        Comment


        • #5
          Re: A few thoughts...

          agreed.

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