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Old Mar 03, 2012, 02:29 PM
FSD
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Aileron Differential - Rudder

I was just curious what other people use for aileron differential. Typically I use about 10% less on down than I do for up. Anyone else have different percentages?

The same goes for the rudder. I will mix in rudder to aileron at around 15% left for left and 15% right for right.

Just curious if others use differential and rudder mix.

-Paige
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Old Mar 03, 2012, 03:46 PM
Phil.T-tailer
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For the aerobats (Voltij & Kulbutin) - zero differential - for the same control response upright and inverted.
Rudder - yes, if I'm soaring to gain height (or very light conditions), with the flaperons drooped a bit (camber flaps) - then I'll switch in a mix of 30% rudder to keep things tidy. For aerobatics, rudder mix switched off.

For the fast 3m molded ships - I have diff set in the ratio of 3 up vs 2 down, and also switch rudder in for slow flying / soaring, 60-100%. (The dedicated F3F guys spend ages fiddling with diff - I just set it & fly)

Phil.
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Old Mar 03, 2012, 04:43 PM
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Thanks Phil. I appreciate your feedback. I appreciate it.

-P
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Old Mar 03, 2012, 08:46 PM
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Paige:

I use zero aileron differential with my acro ships... for the same reason Phil mentioned; I want upright and inverted performance as equal as possible. If I see any adverse yaw issues, I use a bit of pro rudder manually. I am constantly making rudder inputs as I fly; it has become second nature.

For a pure thermal or slalom glider it might be useful to have some aileron differential to avoid the adverse yaw issue (less drag than using rudder correction) and to fine tune the nose entry angle for most efficient turning.

I do not use an aileron to rudder mix for the same reason. Also I find that when I am flying thermal turns, I initiat the turn with pro rudder and pro aileron; but eventually have to add anti aileron to keep from falling into the turn.

Dawson
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Old Mar 03, 2012, 09:12 PM
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Same as Dawson for me. I guess it depends upon what style of flying you are aiming for.
For aeobatics, diff and rudder mix are not required and are counterproductive.
As a full size glider pilot, I am averse to ail/rudder mix anyway! (or prejudiced some might say! )
I entered into an extended discussion/debate with others on another thread regarding aileron/rudder mix. I'll see if I can find where it was.

Jim.

edit: It starts about here: http://www.rcgroups.com/forums/showt...34497&page=141
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Old Mar 03, 2012, 09:13 PM
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Makes complete sense Dawson...thanks.

-P
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Old Mar 03, 2012, 11:14 PM
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I should probably clarify my original post. My question about differential was based on a question I got from a customer for a non-aerobat concerning reducing yaw during rolls. While I don't use differential myself on my aerobatic planes, I have used a rudder assist (mix) to prevent a similar problem. From what I have read here, I should probably induce rudder manually and allow it to become second nature (as Awesome Dawsom does). The bottom line is trying to find ways to make axial rolls tighter while reducing yaw. Thanks for the feedback. For the record, I agree with the "symmetrical" approach to settings when applied to aerobats.

-Paige
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Old Mar 03, 2012, 11:15 PM
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Quote:
Originally Posted by Jimbello View Post
Same as Dawson for me. I guess it depends upon what style of flying you are aiming for.
For aeobatics, diff and rudder mix are not required and are counterproductive.
As a full size glider pilot, I am averse to ail/rudder mix anyway! (or prejudiced some might say! )
I entered into an extended discussion/debate with others on another thread regarding aileron/rudder mix. I'll see if I can find where it was.

Jim.

edit: It starts about here: http://www.rcgroups.com/forums/showt...34497&page=141
Hey...thanks Jim. Should be a good read.

-P
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Old Mar 04, 2012, 12:28 AM
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My personal experience is ,it depends on the model . For instance a scale DG600 would not respond cleanly without diff on the ailerons actually 100% up 50 % down and without out rudder input would drag its tail low . 50% rudder mix to aileron on a switch takes the drama out of this ,of course you still have the option of doing it manually with the mix switched out ,but that's like not using the cruise control in your car IMHO Typically smaller PSS stuff fly's fine on aileron elevator with equal throws .The best thing about the modern radio's is the ability to mix controls and get the best possible flight performance from the model. Not using the functions sort of defeats the purpose of buying a radio that has that capability in the first place I feel . All my large PSS models run diff and mix and it makes them a joy to fly .
just my 2 cents.
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Old Mar 04, 2012, 12:30 AM
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While proper ruddering can help with making rolls pretty, it's probably more important to treat the cause than the symptom.

In my experience, non-axial rolls can be caused by a number of things:

- Too much total aileron throw
- Too much aileron differential
- Differential setup incorrectly (more down than up)
- CG is off
- Rudder > aileron mixing is turned on

Those are all things worth fiddling with. Rudder > aileron mix won't help and in fact will hurt, as you'll get the wrong rudder input for the first 180* of the roll (assuming upright entry) and this will cause the nose to drop and the roll to generally look non-axial.

I have some mechanical aileron differential on a couple of planes, but none mixed in. I just use the rudder.

Steve
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Old Mar 04, 2012, 01:29 AM
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Quote:
Originally Posted by steve wenban View Post
My personal experience is ,it depends on the model . For instance a scale DG600 would not respond cleanly without diff on the ailerons actually 100% up 50 % down and without out rudder input would drag its tail low . 50% rudder mix to aileron on a switch takes the drama out of this ,of course you still have the option of doing it manually with the mix switched out ,but that's like not using the cruise control in your car IMHO Typically smaller PSS stuff fly's fine on aileron elevator with equal throws .The best thing about the modern radio's is the ability to mix controls and get the best possible flight performance from the model. Not using the functions sort of defeats the purpose of buying a radio that has that capability in the first place I feel . All my large PSS models run diff and mix and it makes them a joy to fly .
just my 2 cents.
Well, I agree that if you have a modern radio that has all of this ability, it should be explored to the fullest. One thing for sure....with all of this programming ability, it makes for even more "personal" input. A pilot can have a certain amount of skill that can either be masked or exposed depending on your programming skills.

I try not to look at it as too daunting...but rather an opportunity to take advantage of your radio's abilities.

Thanks Steve...

-Paige
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Old Mar 04, 2012, 01:34 AM
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Old Mar 04, 2012, 01:37 AM
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Quote:
Originally Posted by surfimp View Post
While proper ruddering can help with making rolls pretty, it's probably more important to treat the cause than the symptom.

In my experience, non-axial rolls can be caused by a number of things:

- Too much total aileron throw
- Too much aileron differential
- Differential setup incorrectly (more down than up)
- CG is off
- Rudder > aileron mixing is turned on

Those are all things worth fiddling with. Rudder > aileron mix won't help and in fact will hurt, as you'll get the wrong rudder input for the first 180* of the roll (assuming upright entry) and this will cause the nose to drop and the roll to generally look non-axial.

I have some mechanical aileron differential on a couple of planes, but none mixed in. I just use the rudder.

Steve
Thanks Steve...of course if we are speaking of these aerobats performing tumbles and whatnot, the CG is going to be way off. Your point that one could have too much aileron throw is right on (from my experience). I tend to dial everything up pretty high on high rates and pay the price on decent looking rolls. I suppose it's like everything else....you may gain something on one end but lose on the other.

-Paige
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Old Mar 04, 2012, 02:25 AM
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What I mean re: CG - if the plane is too noseheavy, it may be carrying sufficient elevator trim such that it won't roll nice and axial, but instead does a sort of barrel thing. Just something else to check.

Steve
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Old Mar 04, 2012, 05:45 AM
Phil.T-tailer
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FWIW / IMHO - Most "wont roll axial" gripes come from folks who dont get up enough speed before the roll
(that, and expecting the plane to do everything for them - not learning the correct sequence of control inputs - not even knowing about adding down elevator through the inverted part)

Phil.
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