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CG for SE5a

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Old 06-24-2013, 11:21 AM
  #1
frankolin42
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Default CG for SE5a

need the CG for and SE5a WW1 biplane fighter. the plane has a 40"WS and weights roughly 3.5 lbs. it is not to be flown 3D, just a typical floater. Thank You
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Old 06-24-2013, 11:59 AM
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limeybob
 
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Default RE: CG for SE5a

use this as a guide.

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Old 06-24-2013, 02:33 PM
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All Day Dan
 
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Default RE: CG for SE5a

Measure the chord of the top wing. Multiply it by .3. Measure the chord of the bottom wing. Multiply it by .3. Put the CG between the two .3 points like the drawing from limeybob. Dan.
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Old 06-25-2013, 11:02 AM
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BMatthews
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Default RE: CG for SE5a

For your first flights maybe set it to more like .25 to .27 instead of the .3 suggested by Limeybob. It's likely that the .3 would be fine. But as the old saying goes "a nose heavy model flies a little poorly, a tail heavy model often only flies once". If it's doggy in flight and wants to lift the nose aggresively coming out of a dive or when increasing power it's easy enough to shift the CG back a little and re-trim the elevator. Keep shifting it back a little at a time until the model handles nicely while still retaining some degree of positive pitch stability. You don't want to make it TOO neutral. On the other hand the strong positive stability of a nose heavy model is annoying to fly as well since you feel like you're fighting the nose all the time. Just like the Bear's porridge it's best when it's "just right".
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