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Thread: Glasair Wing Heavy

  1. #1

    Join Date
    Nov 2011
    Location
    Lehi, UT
    Posts
    3

    Glasair Wing Heavy

    I have been flying my Glasair for about 3 years, however not much in the last year due to an engine issue I am still trying to diagnose. Anyway, In about the last year the left wing has become heavier, or maybe I am just noticing it more. I can't remember making any real adjustments, except for the elevator. The left side seems to be lower than the right about a 1/4" or less. The only other item would be natural relaxation of the motor mounts. Any ideas on if this could cause the heaviness? If not any ideas on what to try?

    Dave

  2. #2

    Join Date
    Aug 2011
    Location
    Pittsburgh, Pa.
    Posts
    86
    Is your glasair an ft? I had a g1ft and many of them with the gear the kit came with end up sitting low on one side or another. Nothing to worry about, just don't fill the gas as high or it will overflow unless you have fuel float valves. As for a heavy wing in flight it is probably that you are flying a little out of trim. Use that rudder! The fuel tank on most glasairs are just one large tank in the leading edge of the wing. If you take off and forget to use enough rudder you will sling the fuel to the left wing. It's an unnerving feeling the first time it happens but if you fly for a while not in a slip or slip to the other side, the fuel will drain back to the middle of the tank and the wing won't feel heavy. (I know this from first hand experience) good luck, hope you get the engine problem worked out soon.

  3. #3

    Join Date
    Aug 2011
    Location
    tonasket wa
    Posts
    8
    You didn't say model or age. Are you talking about flying or sitting on the ground? I have an early G1TD. I rigged the flt controls by the book. At 180 mph IAS the rt wing was heavy, so I leveled the a/c in the hanger and measured from the floor up. The lft flap was lower than the rt, so I raised it to match the rt side. Now at 180 the wings are level but at pattern speed with flaps down the lft wing is heavy. Anyone have a simple aileron trim system?

    Ed

  4. #4

    Join Date
    Aug 2011
    Location
    Wachapreague Va.
    Posts
    129
    Look at the KRNET website and search for trim. They have a simple servo setup that may be just what you are looking for.

  5. #5

    Join Date
    Aug 2011
    Location
    tonasket wa
    Posts
    8
    I'm really looking for a mechanical system, may have to design one.

    Ed

  6. #6

    Join Date
    Sep 2011
    Posts
    72
    Forget measuements of wing to floor. The only measurement that counts is the angle of incidence being equal on both wings, taken at root and mid-aileron. You can do this by making a pair of V-groove blocks which pick up on leading and trailing edges on wing AND flaps /ailerons rigged for flight positions, and a horizontal beam with vertical risers from the blocks. The intention is to measure the incidence on both wings and if they are off by 1/2 deg or more, this will cause a wing heavy situation on the side having lower incidence. Measurement can be made with a digital level on the horiontal beam that goes down to tenths of a degree.
    If you find angles are off/different between sides, you can correct situation by moving a rear spar up or down and rebolting ( a pain). Or you can droop a flap slightly by putting in a spacer where flap and rear spar come in contact, so flap has permanent droop on the heavy side, providing slightly higher lift there. A typical spacer would be 1/8" thick. Or adjust flap position with rod control for proper droop. You want the droop to make the angle of incidence equal on both wings around root.
    Bob H

  7. #7

    Join Date
    Aug 2011
    Location
    tonasket wa
    Posts
    8
    Glasair wings are one piece tip to tip. Move one side and the other follows. Incidence is set up using factory measurements on the fuselage sides. Cutouts made and brackets installed.

    I bought a mechanical aileron trim sys from Vans, I think it will work.

    Ed

  8. #8

    Join Date
    Sep 2011
    Posts
    72
    Main point is to assure equal incidence at root with wing/flaps and adjust position of flaps to provide that. It takes very little droop to change angle.

    On Pulsars, factory screwed up and offset fuselage reference point so all 2-piece wings were off and made LH wing heavy. The fix was to try and adjust rear spar position to fuselage. I ended up drooping flap slightly. Worked very well.
    Good luck.

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