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Thread: Acro Question?

  1. #1

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    Acro Question?

    Could anyone who has considerable acro experinence give me an answer to 2 questions? And any informed opinion is fine.

    1. Is there a max wind limit for an acro contest, with the usual planes, Pitts , Yaks, Extras, Decathlons, etc.?

    2 If someone is doing a half cuban 8 in a warbird, say P-51, or T-6, what g force do you think they reach?

    Thanks

  2. #2
    RetroAcro's Avatar
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    1) Per IAC rules: "Flight will not be conducted if the wind speed exceeds 20 knots, except at the discretion ofthe Contest Jury."

    2) Are you asking about a competition quality figure, or an airshow cuban? Of all the warbird (airshow) acro I've seen, I'd guess they don't typically pull more than around 4G for any given figure. It's completely up to the pilot what kind of G you want to put on the airplane. I've done all the basic figures in a T-6, and they were all right around 4G. But the looping portions were not actually round. Given a particular aircraft's airspeed/power combination, you'll need a certain amount of G to make a looping figure round - as in the 5/8 loop in a cuban. Most warbirds to do not actually do round loops, so a "display" loop or cuban could be done at lower G than an actual round competition cuban, which may require more airspeed and a harder pull, depending on the airplane. You planning on bringing a T-6 to a contest? :-) I was once at a contest that had a T-28 participating. Now that was entertaining.

  3. #3

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    The answer to the wind question in practice is that the contest jury polls the competors and decides to fly unless there is a real safety issue. I have seen something like 40kts in the box (took home 1st place Intermediate that time). We go to contests to fly, not to sit, so we fly. I have seen contest flying put on hold due the wind across the only runway. Everyone agreed that it was good policy to not get the less experienced pilots in over their head when taking off and landing. So we sat for a couple of hours. But if the wind handicaps everyong equally, the vote is to fly.

    As for the warbird guys, the ones that I have spoken to generally fly to +4G and no negative. Warbird acro is generally smooth and flowing in deference to the age and value of the airframes.

    Hope this helps,

    Wes
    N78PS

  4. #4
    Joe Delene's Avatar
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    Most any maneuver can be done at 4G or less.

  5. #5
    steveinindy's Avatar
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    A T-28 doing aerobatics? Now that would be a weird sight and probably a pretty interesting noise as well. LOL
    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.



  6. #6

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    Two or three years ago, at the Warrenton, VA East Coast Aerobatic Contest, a local T-28 owner entered and flew Primary. He started higher than the top of the box so that he has plently of room for the spin. He flew safely, I think that he scored OK, and the gallery was greatly entertained. Have not seen that since though.

    Competition aerobatics has several dimensions of performance that you must manage. One is that the box is 3500' wide, 3500' deep, and 3500' high. I will hazard a guess that in a large, heavy, machine like a T-28 the box seems really really small and wrestling it through the figures in that space is really really hard work. Its an arena for ballerinas, not WWE wrestlers.

    Wes
    N78PS

  7. #7
    RetroAcro's Avatar
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    Yeah, that same T-28 flew Sportsman at Warrenton a couple years ago just for fun. It could do everything OK except for the hammerhead. It seemed to have a lot of torque and not a lot of rudder. It got near the top, and he tried to pivot it, but it just torqued off about 90 degrees before flopping back down, and he continued the sequence on the Y-axis. Not sure if he didn't notice or didn't care. Probably didn't care, he was just having fun...so were we :-)

  8. #8
    AcroGimp's Avatar
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    The box seems small in an Extra 300L, at least to me it does. At 180 KIAS you cross the entire box in a little over 12 seconds with no wind.

    I would love to see a T-28 do it, Trojan is a favorite of mine.
    Whether you think you can, or think you can't, you're right.

    EAA Chapter 14, IAC Chapter 36

    http://acrogimp.wordpress.com/

  9. #9
    steveinindy's Avatar
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    How big is an aerobatic box just out of curiosity?
    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.



  10. #10

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    Quote Originally Posted by steveinindy View Post
    How big is an aerobatic box just out of curiosity?
    From rev. Jim memory, 1000 meter cube.

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