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Dihedral Self Correction and Vertical Balance Point.

Old 01-27-2016, 06:57 PM
  #26  
Rockin Robbins
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Originally Posted by fhhuber View Post
But it was a simple enough explanation for the question that started the thread...

And the "I'm smarter than you" wasn't needed.
I never said that fh. If my intention was to belittle you I would have done the math. As it was I merely alluded to math I trusted you have the ability to perform to verify what I said.

It's a non-intuitive result. Differential lift makes so much sense we don't think we have to look any further. I am included in that "we." It's only when we abandon what "makes sense" and do the implied math that we discover that in this case the truth just isn't that easy.

Common sense isn't. That is no reflection on who is smarter than who.
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Old 01-27-2016, 07:44 PM
  #27  
fhhuber
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We didn't have to look further because... It was enough to satisfy the question..

WTF can't someone accept a SIMPLIFIED answer when it is announced that it is SIMPLIFIED?
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Old 01-27-2016, 11:54 PM
  #28  
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Old 01-28-2016, 07:56 AM
  #29  
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C'mon guys ..... let's not develop RCG style on WF ....

Kiss and make up !

Nigel
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Old 01-28-2016, 06:32 PM
  #30  
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Originally Posted by solentlife View Post
C'mon guys ..... let's not develop RCG style on WF ....

Kiss and make up !

Nigel
yeppers ,, be nice guys
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Old 01-28-2016, 09:09 PM
  #31  
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Thought I was being nice. It's a blow when someone rejects help as some weird rebuff of unimaginable nature. And then when they continue after I explained that I wasn't putting him down in any way, just explaining the dihedral situation. I thought learning the truth was fun, not offensive!

After all, the differential lift explanation doesn't do anything to explain why a 3-channel plane banks and turns with rudder application! By the way, the curved path is carved out by the elevator, not the rudder. That is what actually makes the plane turn. Extra tidbit: have you ever considered that the immediate effect of rudder application is to bank the plane AWAY from the intended direction of the turn? What banks the plane the way it does, OPPOSITE the rolling torque applied by the rudder?

Anyway, sorry if I offended anyone. Was just trying to explain how things really work in an interesting manner. None of that was directed at fhhuber, nor was he even mentioned in the post. I can't see how I ruffled any feathers there.

Last edited by Rockin Robbins; 01-28-2016 at 09:29 PM.
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Old 02-22-2016, 03:04 AM
  #32  
birdDog
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It actually flys pretty darned well. Levels out like a trainer. Thanks for the advice and discussion folks. Hopefully get out in less than 15mph winds next time.
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Old 02-22-2016, 09:27 PM
  #33  
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personally I would shorten that nose by at least 3/4 of its length as that could add to instability in a turn with a long moment like that. Certainly won't help the dihedral. It also makes the rudder less effective.
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Old 02-22-2016, 09:35 PM
  #34  
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Good advice. She was pretty sluggish about turning. I wound up with that length as a simple way to balance by sliding the saddle along the length.
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Old 02-22-2016, 09:51 PM
  #35  
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I experimented with a similar, but larger plane many years ago. That is why I suggested it. You could of course move the main wing forward a little but this can cause tail heavy problems. You will still have to add weight to compensate for shortening the nose but because the weight is closer to the CG it does not affect the turning as a long nose will.
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Old 02-22-2016, 11:29 PM
  #36  
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The long nose is not an issue due to weight location. Its the side area affecting yaw stability. Too much side area too far forward compared to the side area aft. The fin/rudder is big and far back in order to give yaw stability. Extend the nose, increasing area plus having that added area far forward and you may need a bigger fin.

This is the basic reason that you see a sub- fin added to a plane when they add floats. The floats will typically add side area slightly more forward of CG than aft when you need more aft of CG than forward for good yaw stability.
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Old 02-23-2016, 08:38 AM
  #37  
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The dihedral angle looks a little marginal to me. For good turning on rudder you should try increasing the angle.
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Old 02-25-2016, 07:42 PM
  #38  
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Originally Posted by JetPlaneFlyer View Post
The dihedral angle looks a little marginal to me. For good turning on rudder you should try increasing the angle.
I agree. Looks like the center section is virtually flat and the outside wing panels have little angle. Increasing both so you have about 5 dihedral with a bit more on the wingtips would make the plane more stable and more responsive to rudder.

Of course you could add ailerons to your present configuration and the plane would respond well.
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