How many do Ail to Rudd mixing?? - RC Groups
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Nov 06, 2014, 08:22 PM
E sailplane thermal hack
Poll

How many do Ail to Rudd mixing??


How many of you use Ail to Rudd mix??
How many use completely separate Rudd and ail with no radio mixing??

Jerry
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Nov 06, 2014, 09:14 PM
Team Hello Kitty
SoaringDude's Avatar
Are you trying to solve a specific control problem or just curious?
Nov 06, 2014, 09:57 PM
E sailplane thermal hack
Curious
Nov 07, 2014, 12:03 AM
Team Hello Kitty
SoaringDude's Avatar
I use ail-to-rudder mixing in all flight modes but I also use the left rudder stick.

My rudder mix varies by flight mode: most rudder is mixed in THERMAL, LAUNCH, and LAND modes, less in CRUISE (NORMAL mode in Airtronics TX terminology), and even less in REFLEX.

I lead all turns with the rudder stick. I also use the rudder stick to override the coupled rudder that comes when I have to apply opposite aileron to maintain a balanced thermal turn. For me the ail-to-rudd mix greatly reduces pilot load when flying.
Nov 07, 2014, 09:37 AM
Registered User
I too use ail to rudder mixing in varying degrees of coupling strength depending upon flight mode. But I also use rudder stick especial to initiate a turn.
Last edited by jpherit; Nov 07, 2014 at 04:40 PM.
Nov 07, 2014, 10:16 AM
Good for what ALES you
awilmunder's Avatar
Yes on the Ail->Rudd mix. For reasoning, look up 'adverse yaw' in wikipedia.

Now the question is how much compensation. Philip Kolb, designer of the Pike series of planes, made this recommendation. To check if you have the proper amount of mix, you should be able to fly in a straight line, roll left and right with your ailerons, and the plane should continue in a straight line. This is the perfect roll.

Here's where Philip and I differ and others with far more experience with both model and full-size sailplanes may be about to give me an education...

We are flying sailplanes, not aerobatic planes. Nobody is judging us on whether our roll is perfectly straight. Why would you want to just roll anyway except as part of a more complex maneuver. When I use my ailerons, it is usually for changing course or circling in a thermal, so more for banking than rolling. You can use a roll to level your wings, but your wings may have just told you that you have greater lift on one side, so you shouldn't roll to level out, you should bank into that lift instead.

Roll and bank are often used synonymously, but I think of roll as a single axial movement, while bank is like the turn in a racetrack. Since my intent is to bank my plane, not simply roll it, I mix in enough rudder that if I am in a straight line and apply left aileron, my plane will very gently begin to enter a turn. If I alternate left and right aileron, my plane will do a very shallow S pattern.
Nov 07, 2014, 11:17 AM
Team Hello Kitty
SoaringDude's Avatar
When I started trying to optimize ail-to-rudder mix on my planes a few years ago I ran into inconsistent results until I dug deeper (thank you RCG!) and discovered the strong interplay between rudder coupling, aileron throws, and aileron differential. The adjustment process was a little easier back when I didn't really care about roll rate but in the last year that has turned out to be an important requirement (faster roll rates allow you to quickly bank into a thermal that you otherwise might miss). Preserving a faster roll rate and keeping thermal turns efficient was not so easy (for me).

I ended up cut-and-pasting a bunch of helpful text on this from various RCG posts into a single document that I have shared with a few members already. If I was going to choose a single post that best encapsulates how to go about setting your aileron, differential, and rudder mix parameters it would be this one. See the paragraph that starts with "Ail/Diff/Rud mix setup process:". Flying sharp figure eights as a setup test has worked well for me.

Chris B.
Nov 07, 2014, 03:44 PM
E sailplane thermal hack
Thanks guys!! The main reason I'm asking,, is,, according to many experts it's important to learn separate manual rudder and aileron and using them in different amounts depending on conditions.,, so I started putting my Rudd to aileron mix on a 3pos switch,, so it can be off, or two other mix amounts. I'm finding that I'm slowly learning,, but,, it's very difficult slow process. Worth the effort you think??? Or should I just try to find the right combination of ail differential and rudder mix?? Fortunately cause of the pulsars long tail moment, big rudder, and slow flying speed I think it makes the ideal trainer for this,, as its readily apparent what affect each input has. I'm finding that when I get it just right,, that is starting with rudder and aileron,, releasing ail,, keeping necessary amount of rudder to steer,, and maybe occasionally using aileron to control bank angle.,, I can get a very efficient flat turn,, but it requires ALOT of thinking.

Jerry

Ps edit : GT of F3K world and Mark Drela are the guys I believe who strongly advocate learning separate
Manual coordination of Rudd and ail
Last edited by Airman74; Nov 07, 2014 at 03:51 PM.
Nov 07, 2014, 04:26 PM
E sailplane thermal hack
Hmmm interesting article Chris. I do see the point about being able to maneuver quickly into the lift. Didn't think about having increased diff with different flying speeds though. Ok good to know!! That separate coordination was too hard anyways,, so back to the drawing boards I guess... At one point I was using 125% Rudd to ail mix. I'll try the roll test

Oftentimes learning the skills of good thermal flying seems to be a two steps foward one step back kind of a thing ;-)
Nov 07, 2014, 07:45 PM
Team Hello Kitty
SoaringDude's Avatar
Quote:
Originally Posted by Airman74
...according to many experts it's important to learn separate manual rudder and aileron and using them in different amounts depending on conditions.... Jerry
Many of those experts are guys who did their RC learning back when transmitters did not support mixes. True, you could learn to fly without rudder mixing, or any other modern computerized mix for that matter, but mixes make your flying a whole bunch easier.

Want a real challenge? Set up your molded high performance plane without any mixes other than L/R aileron control w/ zero differential: flaps and rudder on the left stick, and elevator and ailerons on the right stick. No flight modes, no camber, no rudder mix, no flap-to-elev comp, etc. I'd like to come out and watch if you do
Nov 07, 2014, 09:39 PM
E sailplane thermal hack
I could do it!! All except for the flap to elev comp,, I grew up flying slope planes pre computer radios. With a little practice I probably could land without elev comp too!! Although it wouldn't be pretty ;-)
Nov 23, 2014, 11:15 PM
NCSS / SVSS Flyer
Joe Wurt's appendix for JR9303 programming is a great shortcut to setup mixes, a little fine tune and you're there.

Tom Copp's for slope is a very good start too
Last edited by SlopeRC; Nov 23, 2014 at 11:15 PM. Reason: Sp
Nov 24, 2014, 05:14 PM
tpczx6
tpczx6's Avatar
Tom's site
http://www.f3x.com/
go to how area
I have it set as model 30 in 9303 and when I program a new plane I just copy to new model and set trims