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Thread: Overloads

  1. #1
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    Default Overloads

    The POH for my old (1984) turbocharged C-206 amphibian shows a Flight Load Factor of 3.8 with flaps up. It also shows that the design load factors are 150% times this number, and that the structure meets or exceeds design loads. Does someone out there want to interpret those numbers

    I realize that we all boo and hiss about overloads, but many of us seldom flew without an overload. So, what do the load factors and the multiplier really mean . . . . .

    I'll bet FloatPilot has a pretty good idea . . . . .

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    Default

    That's +3.8 G. That isn't addressing weight. Obviously there's a correlation because utility category weights are usually less than normal category. I've never been too concerned. +3.8 G is more than I'm comfortable with in these little old airplanes. When it gets bumpy I'm happy to lope along at the Va that's appropriate for my weight.

    I'd think a guy could figure the wing loading and multiply it by 3.8 and assume the aircraft structure could carry that weight in smooth air but the controls wouldn't be very effective and any operating speeds would be a guess.

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    Quote Originally Posted by Mr. Pid View Post
    That's +3.8 G. That isn't addressing weight. Obviously there's a correlation because utility category weights are usually less than normal category. I've never been too concerned. +3.8 G is more than I'm comfortable with in these little old airplanes. When it gets bumpy I'm happy to lope along at the Va that's appropriate for my weight.

    I'd think a guy could figure the wing loading and multiply it by 3.8 and assume the aircraft structure could carry that weight in smooth air but the controls wouldn't be very effective and any operating speeds would be a guess.
    Yep, it's G-factors of course.

    Yeah, but I can't easily find the square foot wing area that would be required to calculate the wing loading psi or psf. No longer have that C-206 so that I could measure it.

    You're right, of course, about penetration speeds. I wonder how many of today's pilots know that maneuveringn speeds allow the wings to temporarily stall before heavy wing loading occurs?

    Low and Slow . . .

  4. #4

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    I can help here I think. The 3.8G thing is the "limit" load of the aircraft. That is the maximum load that the structure can be subjected to, and it not cause any part of the structure to be permanently deformed, or bent as it may be called. For example, a 60 degree banked turn at constant altitude subjects the aircraft to 2.0 G's of load. This will not cause any permanent damage or "change" as it may be, to occur to the aircraft, because the airframe will withstand 3.8 G's and not become "bent". This is considered the "normal operating envelope" of the aircraft, both structurally and aerodynamically (3.8G). The 150% (5.7 G's) thing is the "ultimate" load, or the max load you can subject the aircraft to, and not have something break. If you subject the aircraft to say 4.5 G's, it will bend but not break. It will get you home, but you then have repairs to make! If you subject it to 6.5 G's, you probably won"t make it home.

    Regards,
    Bruce

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    Quote Originally Posted by cessna308 View Post
    I can help here I think. The 3.8G thing is the "limit" load of the aircraft. That is the maximum load that the structure can be subjected to, and it not cause any part of the structure to be permanently deformed, or bent as it may be called. For example, a 60 degree banked turn at constant altitude subjects the aircraft to 2.0 G's of load. This will not cause any permanent damage or "change" as it may be, to occur to the aircraft, because the airframe will withstand 3.8 G's and not become "bent". This is considered the "normal operating envelope" of the aircraft, both structurally and aerodynamically (3.8G). The 150% (5.7 G's) thing is the "ultimate" load, or the max load you can subject the aircraft to, and not have something break. If you subject the aircraft to say 4.5 G's, it will bend but not break. It will get you home, but you then have repairs to make! If you subject it to 6.5 G's, you probably won"t make it home.

    Regards,
    Bruce

    Pretty good so far. Can anyone tell me the square footage (the area) of a C-206 wing? Or can anyone supply "plan" dimensions of the wing? Not simply length and width or chord, since the wing tapers . . . . . ?

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    Quote Originally Posted by Grizzly 1 View Post
    Pretty good so far. Can anyone tell me the square footage (the area) of a C-206 wing? Or can anyone supply "plan" dimensions of the wing? Not simply length and width or chord, since the wing tapers . . . . . ?
    1984 TU206G
    Wing area- 174 sq ft
    Wing loading- 20.7 lbs/sq ft
    Power loading- 11.6 lbs/hp (a standard U206G is 12 lbs/hp)

    For what its worth, Cessna models 172, 177, 180, 182, 185, 205, 206, and 207 all share the 174 sq ft wing area. The 206 and 207 have the unique short ailerons/big flaps, but all have equal wing area.

  7. #7

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    I own a C177A. All Cardinals, as we call them, have a lightened version of the same wing that is on all 210's from 1967 model year on. It is a fully tapered wing, with no corrugated skins like the other Cessna singles. Cardinals and 210's even have the same total wingspan, and the wings would bolt up interchangeably, except for fuel and other fittings. The 210 has thicker skins and spar caps, etc., and a slightly different amount of wash out.

    Regards,
    Bruce

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    Quote Originally Posted by Mr. Pid View Post
    1984 TU206G
    Wing area- 174 sq ft
    Wing loading- 20.7 lbs/sq ft
    Power loading- 11.6 lbs/hp (a standard U206G is 12 lbs/hp)

    For what its worth, Cessna models 172, 177, 180, 182, 185, 205, 206, and 207 all share the 174 sq ft wing area. The 206 and 207 have the unique short ailerons/big flaps, but all have equal wing area.
    Thanks, Mr. Pid. I Iknew you could do it!!!!!

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