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rolls not axial

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Old 07-18-2005, 12:56 AM
  #1
fredo
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Default rolls not axial

Hi Don, I have a new 2.3m Comp.ARF Extra with DA50 and KS tuned pipe. So far I have done only 6 flights with it......still trimming and trying to get used to it, but I have noticed when I try to do a slow roll the plane side shifts soon as it gets to knife edge and describes something what looks like a mini barrell roll rather than nicely drilled axial one. I haven't got ailerons set to differential. Could that be part of the problem? Or perhaps the engine thrust line or CG? As you probably know this plane with this particular set up have some CG issues and is right on the mark if not a little bit tail heavy. I'll appreciate your comments.
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Old 07-20-2005, 11:04 PM
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Default RE: rolls not axial

yap, i have the same problems too especially when the plane speed is too slow.

would like to hear from the expert. thank you.
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Old 07-22-2005, 10:56 PM
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Don Szczur
 
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Default RE: rolls not axial

My suggestions only, based on experience with your problems, several years ago. Move the CG forward if you can, the further forward the better. Then on low rate switch, reduce the elevator and rudder expo's, and reduce the elevator, aileron and elevator throw to give you a better locked in feeling, like a pattern plane. Finally, make sure your throttle curve is linear. JR 10X and 9303 have a very nice throttle curve feature for this. That way it will not drop if you move the trottle a little. I only put enough rudder throw in low rate for barely holding knife edge at full deflection, for reference.

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Old 07-31-2005, 06:32 PM
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Default RE: rolls not axial

Thanks Don, will try that.
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Old 08-11-2005, 03:43 AM
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Default RE: rolls not axial

Hi Don, grest reply!!!

I was thinking about your suggestion regarding moving the CG forward. Can it be applied to all airplanes? I mean: this operation also improves rolls with fuselages that have an aft center of pressure?

For example, I'm currently flying with a plane whose fuselage side area is concentrated towards the canopy, behind the wing (let's say similar to a Katana) - so behind the CG also - Initially I was flying with a little forward CG in order to track well, but I noticed that the airplane falls down when I put it in knife-edge! Hence, also rolls were not so good. Now I fly with a after CG and to me rolls are much more better!!!

What is your opinion on this?
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Old 08-12-2005, 10:39 PM
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Don Szczur
 
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Default RE: rolls not axial

I've never flown an airplane that was too nose heavy. Having said that rolls are better with the CG not forward, except if its back too much the rolling circles go out the door, along with just about all the horizontal lines. That's the trade off. I like the locked in feel of a forward-CG model. The CA Extras are particularly applicable to this.

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