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3-d elevator effectiveness

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Old 03-06-2002, 08:54 PM
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Johnny_Rebel
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Default 3-d elevator effectiveness

Does anyone know why in 3-d down elevator is so much more effective than up? - Given that up and down throw is the same.
thanks in advance for your insight.
-Jon
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Old 03-07-2002, 05:24 AM
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Noflyzone
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Default Down Elevator Effectiveness

Hi Jon,

The aerodynamics are way too boring, so here's my attempt at simplicity. When in 3-D, up elevator is farther from the wing's influence than down elevator. Plus, depending on the airframe, up elevator can be bucking the weight of the wing as well (vertical C/G). Hope this helps...

Dan
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Old 03-07-2002, 09:37 AM
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Default Not Sure about that Dan

But my unscientific guess would be that while inverted the elevator is in cleaner and just plain more volumes of air. Deflection and air over the surfaces at near stall speed is what it's all about. Where are the Gurus when you need them
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Old 03-07-2002, 12:14 PM
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ChuckN
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Default 3-d elevator effectiveness

I have no doubt it's because of the vertical CG. Look where the wing is mounted on scale aerobatic aircraft. And wings ain't light!
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Old 03-08-2002, 08:37 PM
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Default 3-d elevator effectiveness

My guess would be the location of the wing relative to the thrust line. If the wing is lower, then up elevator is more sensitive and visa versa. I didn't have the skill to test this last summer on my stik but I sure will this spring.
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Old 03-08-2002, 08:43 PM
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Mike James
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Default Thrust line, Wing, and Stab

Hello everybody,

Now this is getting interesting...
Please refer to the other thread here, "Wing and Stabilizer Arrangement for Aerobatics". These are exactly the kinds of issues I'd like to explore here. Where are all the Pattern and IMAC designers? (the people who invented most of the things we fly) Seems like they don't visit this forum...?

Specifically, I'm searching for opinions on what is absolutely the most "neutral" arrangement for the best aerobatics in every axis. It could be that a "cruciform" arrangement is one answer, but I'd like to find the best combination for a relatively "conventional" aircraft.
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Old 03-08-2002, 09:25 PM
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Johnny_Rebel
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Default another thing

Another thing i'm baffled by is that it seems that in precision flying down elevator is much less effective then up- 3-d is just the opposite- any ideas? also i've noticed this on caps and extras - those are the only bigger sized models i've flown
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