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Old 11-10-2015, 07:22 PM
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JetPlaneFlyer
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Join Date: Mar 2009
Location: Aberdeen, Scotland
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FWIW and to the best of my knowledge, the dive test was originally devised for sailplanes, and it actually works best on sailplanes or at least models that are quite clean and efficient aerodynamically (more draggy models need a very steeper dive angle for it to work)...
Anyway, sailplanes rarely if ever have symmetrical airfoils and it works 'as advertised' on them.

It's always worked well for me though for aerobatic models I prefer to use the inverted test to set CG i.e. trim the plane for level upright flight, roll inverted and observe what it does 'hands off'
  • For 3D it should fly level or very gently arc downward.
  • For pattern and sports type acrobatics it should arc down a little more.
But personal preference comes into play too. Trimming for 'hands off' level inverted flight does make the plane a little tricky in some aspects of flight, like the ballooning up when you slow down that fhhuber mentioned.
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