Trimming the Aerodynamics of Your EZ
October 1981
Like any other aircraft, the trim and stability of a VariEze or Long—EZ depends on correct cg position and proper contour and incidences of all flying surfaces. There Is an easy way to verify that your aircraft is rigged properly with the incidences correct. This Involves flying at several airspeeds while monitoring the elevator position, then comparing your data with the design information. Measuring elevator position in flight is simple since the pilot can easily see an indicator attached directly on the elevator surface.
If your EZ does not handle, perform and stall exactly as described In the Owners Manual it could be due to an improper incidence or contour of the wing, canard or elevator, and you should conduct the test below to see if your elevator is at the correct position. If the elevator position is not correct, your airplane may also have a large trim change when flying into rain. Fabricate the plate and needle from .016 2024 aluminum. Paint the plate white and the needle black.
Mount the plate to your outboard elevator fairing and the needle to the elevator (use 5 minute epoxy it will later peel off without damaging your paint job). Calibrate elevator position (plus Is trailing—edge—down) using your elevator position template from Chapter 11, page 6, making a mark on the white plate every 2 degrees. Now, load your aircraft to the mid—cg position (99 for VariEze and 101 for Long—EZ). Fly In stabilized conditions, smooth air in level flight at 70, 80, 90, 100, 120 and 140 knots indicated. Plot your elevator VS speed data on the graph shown below. Your data should fall within the limits shown. RAF is interested to see the variations of this data occurring due to tolerances from one airplane to another. If you do this test, please send us your data whether or not It is within the limits shown.
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