stunthanger.com
Design => Engineering board => Topic started by: TomLaw on June 30, 2012, 08:15:51 PM
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Horn offset doesn't matter.
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Horn offset doesn't matter.
Huh????
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What I am showing, in abbreviated format, is that if the flap horn and elevator horn are not equidistant from the plane's centerline, it will have no effect on the control behavior.
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not sure how relevant that is ,, the centerline of the airframe isnt whats important from my graphic calculations,
what matters is the geometry between the horns irrespective of the centerline. how the horns relate to each other will have an effect on the control response linearity.
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d2 -d1 is just the horn offset. It doesn't matter how far either is from the centerline.
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The horn offset, especially on the elevator can have a big effect, especially on a profile that does not have a really stiff fuselage. Friend of mine built a mid-size Cardinal with a 40 on it. After the first season it quit doing decent square maneuvers. We tried everything, finally ended up trimming 1/3 off the flaps(it was a pretty light plane). But is still glitched badly especially on the 4th corner of the square loops. I was flying it one day and he noticed that in that corner the whole tail twisted about 20 degrees. The horn was about an inch and a half from the fuse. With some ground testing it was easy to see that any significant force on the elevator would twist the fuselage.
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Very interesting. Could that be blamed on the vertical stabilizer moving, rather than the 'tracking' of the horn?
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The stab on the profile Scott Riese brought to the Salem contest a few years ago rotated about 30 degrees in maneuvers. It was entertaining, but I don't think it helped his score. Thanks for the reminder that we can't assume rigidity.
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I'll admit to be dense on some of the "Engineering" topics. It took me quite a while to even figure out what is being talked about.......... and I have never considered it in any matter concerning my C/L models.
BIG Bear
RNMM/AMM
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... and I have never considered it in any matter concerning my C/L models.
And now you have theoretical justification for not considering it.
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And now you have theoretical justification for not considering it.
Hi Howard,
I am sure you are familiar with the adage that "even a blind hog grubs up an acorn every now and then"............ In my case, I just steal y'all's ideas and things that work. Makes this hobby/sport a LOT easier!
Bill
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Don't steal them from me. You'd be getting them second-hand.
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Don't steal them from me. You'd be getting them second-hand.
It's all good! Second hand or first hand, as long as I get the info I need. ;D
BIG Bear
RNMM/AMM
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Trial and error worked pretty well for the first 4.2 million years!
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Could you translate the Chinese for the rest of us. ???
Lateral Horn Separation - They have lots of them in TX, must be the water.
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Could you translate the Chinese for the rest of us. ?
If I did something like this at work, my boss would send me back to draw a picture of what I was talking about.
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Here you go. Notice that I changed the subscripts on d.