Cessna 150 Aerobat banks to the left

Discussion in 'Maintenance Bay' started by 100hp, Jan 2, 2013.

  1. 100hp

    100hp Filing Flight Plan

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    Bill
    I have a 1972 Aerobat. On my last flight something happened that now causes it to bank to the left.

    It won't fly straight and level without right aileron input. Rudder input doesn't fix the problem.

    Any ideas?
     
  2. dell30rb

    dell30rb Final Approach PoA Supporter

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    Maybe its not the plane, but all of that christmas ham you ate? Not to mention the egg nog.


    Kidding of course.. I was flying a 152 for awhile that had a 'heavy wing' and looking through the service manual provided instructions on correcting this situation. They involved removing the wing root covers and adjusting the bolts that hold the wing to the airframe. I never did the procedure (obviously this is one best left to an A&P) but I recall cams or some form of adjustment at the wing root bolts. The best guess I can come up with is that one of them is loose and slipped.
     
  3. poadeleted20

    poadeleted20 Deleted

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    Have you checked the cable tensions and control surface rigging? Is there any indication it was recently subjected to an over-g condition, say, on a high-g rolling pull-out? Note that the g-loads on the wing in a rolling pull-out can be higher than the g-load indicated on the cockpit accelerometer.
     
  4. dell30rb

    dell30rb Final Approach PoA Supporter

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    From the 152 service manual


     
  5. whifferdill

    whifferdill Line Up and Wait

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    Yeah, don't fly straight and level. :D
     
  6. dell30rb

    dell30rb Final Approach PoA Supporter

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    I should have mentioned that my reply was assuming the OP would have said something if he possibly bent or broke something on the previous flight from over stressing.

    Make sure a mechanic looks the wings/airframe/cables over thoroughly before trying to solve it with adjustments at the wing attachments or elsewhere. Otherwise you might be putting a band-aid over a serious structural problem.
     
  7. dell30rb

    dell30rb Final Approach PoA Supporter

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    You could also just hang a couple of lead fishing weights from the right side of the wheel! That'll fix it ha
     
  8. poadeleted20

    poadeleted20 Deleted

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    Right. That "wing-heavy" procedure from the manual should be looked at only as a last resort after other less drastic causes have been eliminated. It's hard to imagine how an airplane could suddenly have a change in the incidence angle of one wing if it's been flying fine all along unless it were over-g'd, and that would be a serious situation in which simply re-adjusting the wing might just be treating the symptom rather than the disease.
     
  9. 100hp

    100hp Filing Flight Plan

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    The plane has about 6,500 TT. It's no spring chicken.

    I haven't been doing any aerobatics or otherwise stressing the plane, other than a little bumpy air.

    It was flying fine earlier in the day. Nice smooth air.
     
  10. poadeleted20

    poadeleted20 Deleted

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    When were the control surface rigging and cable tensioning last checked?
     
  11. Silvaire

    Silvaire En-Route

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    This is a procedure to follow after re-installing the wings, it's not something that requires periodic adjustment. In this case the first thing I would do is check that the rudder trim tab and any aileron trim tab, if one is installed, has not been bent out of position. If there is an aileron trim tab it's an indication that the rigging was not done correctly so it should be rechecked.
     
  12. SCCutler

    SCCutler Administrator Management Council Member PoA Supporter

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    If the airplane's in-flight behavior has changed that dramatically, all at once, I would be VERY concerned about it, and I'd have it gazed at intently by a qualified A&P.

    It is possible that something broke, or someone bent a trim tab or something worse. Sudden changes in aircraft behavior are not to be trifled with!
     
  13. RJM62

    RJM62 Touchdown! Greaser!

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  14. LDJones

    LDJones Touchdown! Greaser! PoA Supporter

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    Very slight bends in flaps or ailerons can make a bug difference in rigging. Definitely calls for a careful inspection when a change like that comes on suddenly.
     
  15. Dan Thomas

    Dan Thomas Final Approach

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    Rerigging ailerons will not cure a heavy wing. If you rig one downward, the airflow just exerts upward pressure on it and that force is transmitted through the system and forces the other aileron down a bit.

    150s and 152s have no aileron trim tabs.

    Wing heaviness is normally adjusted via the aforementioned eccentric bushings. If this heaviness just appeared, something has been damaged or broken. A dented bottom aileron skin can do it. A failing flap roller can do it.

    Most common cause is a broken rudder bar return spring. The OP says that rudder doesn't fix it, but I'd like to know if the heaviness is still there when he takes his hands off the yoke and holds the ball centered with the pedals. If the heaviness is gone, one of the springs is broken. It's a really common failure point in the 150/172 series.

    Dan