Rudder to Elevator and Rudder to Aileron Mixing?

bobnj · Post by **bobnj** » Sun Mar 16, 2014 6:24 pm

I've looked and looked but haven't found what I'm after yet.

Is there a link to a document or video on how to mix rudder to elevator
so the elevator goes in the same direction with the application of either left or right rudder?

I did a simple mix by adding the rudder to the elevator channel but the servo goes
in opposite directions when applying left and right rudder.

I'm also hoping to do the same with ailerons.
Usually right rudder needs left aileron and vice versa etc.

This would need to be done to each of two aileron, and two elevator servos.

Thanks for any ideas.
Bob

Post by **MikeB** » Sun Mar 16, 2014 6:38 pm

When you set up a mix, you can choose a curve to apply to it. As well as a custom curve, there are some pre-defined ones. One of these is |x| (read as mod x). This uses the numeric value of the source, ignoring the sign so only goes one way whether the source goes either way.

So, on your elevator channel try adding:
+50% RUD curve |x|

Mike.

Post by **jhsa** » Sun Mar 16, 2014 6:53 pm

Try this example

CH1 100% Rud
Ch2 100% Ele
(add) 100% Rud Curve (Curve1)

Now Curve1:

-30, -15, 0, 15, 30 (this will look like an inverted "V". If it goes in the wrong direction just make the "V" positive)

I hope this is a starting point for you and that it helps..

João

Post by **jhsa** » Sun Mar 16, 2014 6:56 pm

Mike was faster

His solution is easier and I recommend it

with mine you can have a visual idea of what is happening.

bobnj · Post by **bobnj** » Sun Mar 16, 2014 6:56 pm

Unless I"ve done something wrong, changing to |x| did the same thing.
Right rudder was up elevator, left rudder was down elevator.

Any thoughts...

Post by **jhsa** » Sun Mar 16, 2014 6:59 pm

I have companion open here and it works..
Add this mix to your elevator channel under the main mix

30% Rud Curve |x|

bobnj · Post by **bobnj** » Sun Mar 16, 2014 8:18 pm

You guys are the BEST!

I'm going to try it for the ailerons now.
Once I get the linear mix under my belt, I'll start pokin for the curve mix where I can adjust
the elevator throw in a non linear fashion.

Thanks so much

More to follow
Film at 11...

Post by **jhsa** » Sun Mar 16, 2014 8:29 pm

One thing is bugging me here and I gotta ask it..

Why would you want to apply opposite aileron to the rudder movement?

João

bobnj · Post by **bobnj** » Sun Mar 16, 2014 8:32 pm

In my experience, left rudder knife edge would necessitate right aileron.

Am I understanding the question?

Post by **jhsa** » Sun Mar 16, 2014 8:41 pm

Ahh, you want to program a maneuver..

Well, it depends on the plane really..
On the one I'm using more at the moment, normally I need nearly full throttle, lift the nose slightly, roll the plane 90º using the ailerons, and hold altitude with the rudder. Ailerons remain more or less centered during the knife edge, just correcting when necessary. elevator then works as rudder keeping the plane flying straight..

But that of course is what I do with my plane. other planes might behave different

João

bobnj · Post by **bobnj** » Sun Mar 16, 2014 8:48 pm

Yes, probably so.
Right now I'm trying to figure out how to get each aileron work with a rudder mix.

I need right rudder = left aileron up - right aileron down.
Left rudder I need right aileron up, left aileron down.

Now I'm in the same boat I was before.
I can get the right rudder to operate the ailerons properly, but the left rudder does the opposite of what I need.

Frankly I'm surprised someone hasn't done this already.
I thought guys were flying pattern and IMAC with this radio?
Maybe not.

It's been a long day...

Post by **jhsa** » Sun Mar 16, 2014 8:58 pm

Well, as far as I'm concerned, I have the bad habit of flying the plane myself

If one of the ailerons does the opposite of what it should, try inverting the curve..

As a side note, if you keep applying ailerons while holding altitude with the rudder, I think the plane will continue rolling. the more rudder you apply, the faster the plane will want to roll.. And you will need normally lots of rudder to mantain altitude on a knife edge

Post by **Kilrah** » Sun Mar 16, 2014 9:39 pm

bobnj wrote: Frankly I'm surprised someone hasn't done this already.
I thought guys were flying pattern and IMAC with this radio?

The IMAC guy will do that compensation himself while flying and give the aileron that's needed to keep it right, which may vary with wind, speed, angle...
Anytime you introduce a mix to help in one situation it will cause disadvantages in others - so instead of correcting for that disadvantage or spending your flight flipping switches to activate / deactivate compensations the easiest is to just learn them yourself.

The more capable the radio is the more we tend to want to use its possibilities everywhere, when sometimes the best is actually to have a setup that's as simple as possible

bobnj · Post by **bobnj** » Mon Mar 17, 2014 6:15 am

I understand and agree with your points regarding "flying" the airplane.
In my mind I use mixes as a tool, and not so much a crutch.

Even the most basic radios have as simple a mix as what I am asking.
There's nothing more user friendly than the 9503, and even that has this
most basic of options.
AND, AND, It is easily adjusted/tweaked at the field.
Will this programming "easily" be tweaked?
That's what mixing is all about, finding the right "mix", isn't it?

So although I don't consider the 9503 the most capable, it has what "most"
people need and use at one time or another.

Just as an aside, my approach to this radio has been to read, watch, gather and
bench test with as much information as I can to learn the system.
I've spent the last month saving files, writing up some basic procedures for things
like flashing etc, and just trying things.
We all know there's a ton of information out there on the Taranis, some new, some old,
some good, some not so good.

So my point is, I'm working with this radio on the bench with a servo board and want to sort
out everything it can and can't do just so I know.

If this rudder to elevator, rudder to aileron mix is out of the ordinary I just want to know that
and figure it out now in the basement, and not at the field.

So in summary,

ABBC3_OFFTOPIC

have a setup that's as simple as possible

is exactly
what I use with the basic canned off the shelf 9503.
I use one switch for all three rates, one switch for the mixing I inquired about here.

I've flown competitively years ago, and at present am in the UAV industry as a lively hood.
In both instances we have tools to lessen the workload on the pilot.
That's all I was trying to convey.

I will spend some time to figure out the best way to do this, study curves and such.
So I'll be back I'm sure with more questions.
These question may seem "sophomoric" to you guys, but to all of us just starting out on this
new journey, they are the most important in the world to us right now.

I've used the Futaba 9ZAPS, and the early ACE MicroPro 8000.
Both were intense and sophisticated for their time.
So is this, so please bear with me.

Thanks so much
Bob

Post by **jhsa** » Mon Mar 17, 2014 9:42 am

Bob, I was just curious about that mixing. Not criticizing you. Not at all. We all do things differently so please do ask your questions. I'm sure we will all learn from the answers.

Joao

Sent from my GT-I9195 using Tapatalk

bobnj · Post by **bobnj** » Mon Mar 17, 2014 9:46 am

Understood brother.

I just wanted to give an idea where I'm coming from.
Sometimes in my excitement, I am not as clear as I could be.

This place is great for getting the information needed to get the system going.

Thank you again
Bob

bobnj · Post by **bobnj** » Mon Mar 17, 2014 12:13 pm

I figured a way to get the ailerons to do what I wanted by using x>0, and x<0 in the curve.
I may have taken the long way around as it ends up needing two entries for left rudder K/E, and two for
right rudder K/E.
So that means when I want to tweak the current linear curve I need to adjust each aileron independantly.
I'll keep pluggin...

Now I also need to figure if that curve can somehow be tailored to use it in a non linear fashion?

So many questions, so little time!

Take care
Bob

davidmc36 · Post by **davidmc36** » Mon Mar 17, 2014 11:21 pm

jhsa wrote:One thing is bugging me here and I gotta ask it..
Why would you want to apply opposite aileron to the rudder movement?

João

I use it for crosswind landings to keep level while ruddering into the wind.

Post by **Kilrah** » Mon Mar 17, 2014 11:30 pm

I would definitely never give that job to a mix, it's just basic piloting skill... each to his own I guess.

Post by **jhsa** » Mon Mar 17, 2014 11:31 pm

Ok.. I guess I do it without mixing just because it's fun to do it the same way real pilots do it..

the real planes I flew before also didn't have any mixing

I find models more difficult to fly though.
But nothing compares to being inside of it and feeling it

will have to do it again..
I do miss it...... a lot

João

G550Ted · Post by **G550Ted** » Mon Mar 17, 2014 11:43 pm

With either a model or full scale, there is no way a fixed mix can accomplish the correct control inputs for any given crosswind except by chance.

Ted

Daedalus66 · Post by **Daedalus66** » Tue Mar 18, 2014 4:11 am

Of course a mix can never replace actively controlling the model, but it can adjust the balance of the controls and their interactions, as well as correcting the handling of the model. In other words, it can help the pilot do the piloting job.

To take a simple example, is it illegitimate to have a flap to elevator mix to manage the pitch change when the flaps go down? I doesn't mean you can avoid controlling elevator, but it makes that control a great deal easier and more precise.

So the problem comes when people think they can avoid having to develop the necessary flying skills through transmitter programming. Many students have this idea and come up with ideas like up elevator automatically applied with aileron to prevent the nose from dropping in turns (just think about the consequences!). In the same league are those who thing the cure for difficulty in landing is to use a flaperon mix (ever tried landing a model with drooped inset ailerons?).

Post by **jhsa** » Tue Mar 18, 2014 8:20 am

flaperon can make the model difficult to control if not correctly set. too much down aileron/flap could make the plane very sluggish on Roll. Close to the ground that is not very good. some mixing can make one situation easier but make other situation more complicated at the same time.. At the end of the day, we do what we think it is right and hopefully learn from our own mistakes.. Not very common in aviation though..

João

bobnj · Post by **bobnj** » Tue Mar 18, 2014 9:12 am

Guys, I get the part about flying and mixing.
I've been in the hobby since 1976, been to Iraq flying UAV's, and am still in the UAV industry.

I'll reiterate and say that I am doing all of this on the bench.
I have not flown the radio or put it in a model yet.
I put some servos on a board and I'm workin hard to understand the system.
What it can do, what it can't do, what's easy, and what isn't.

My goal is to set up a template of options like you might find in any cheaper, less capable radio.
When I set up a model, I'll open up my template and pick and choose which options I want to use, and which I don't.
Sorry if I'm asking sophomoric questions, but once I get past this stage, I'll be ready to go and won't have to slow
down to figure anything out.

So that's it in a nutshell.
It's as easy as it sounds, and as simple as it sounds.

Hope that clears things up...

Daedalus66 · Post by **Daedalus66** » Tue Mar 18, 2014 10:12 am

jhsa wrote:flaperon can make the model difficult to control if not correctly set. too much down aileron/flap could make the plane very sluggish on Roll. Close to the ground that is not very good. some mixing can make one situation easier but make other situation more complicated at the same time.. At the end of the day, we do what we think it is right and hopefully learn from our own mistakes.. Not very common in aviation though..

João

Flaperon with inset ailerons is like having a wing with washin (twisted the wrong way) so the tips tend to stall first. It's a disaster waiting to happen on approach. So not only is it sluggish in roll but apt to drop a wing into a spin.

If you look at how flaperons are used on ful-size aircraft, it's always in conjunction with regular inboard flaps. At the national aviation museum about 2km from here, there's a Dehavilland Beaver on floats with flaps full down (about 80 degrees). The ailerons are drooped about half that amount.

Daedalus66 · Post by **Daedalus66** » Tue Mar 18, 2014 10:17 am

bobnj wrote:Guys, I get the part about flying and mixing.

My goal is to set up a template of options like you might find in any cheaper, less capable radio.
When I set up a model, I'll open up my template and pick and choose which options I want to use, and which I don't.

Hope that clears things up...

Sounds reasonable to me. All this stuff about whether mixing is bad for you is really off topic! Which doesn't prevent me from indulging!

Cheers.

G550Ted · Post by **G550Ted** » Tue Mar 18, 2014 12:55 pm

Don't get me wrong. I, too, believe that mixes are good and like most everyone I use a lot of them. It's just that some try to use mixes that are inappropriate (see discussions above for example). Does not seem that is the case in what bobnj is trying to accomplish, however.

Let me point out to bobnj that his concept of having a library of templates to pick and place when programming a new model may not work out so well with this firmware. Depending on other mix lines, position of mix lines, and other programming, different and unexpected results from a template's intended output may result. I suggest you use your current breadboard experimentation to help understand some of the programming features and concepts of this FW and leave the "old school" canned concepts to those radios where they belong. To do otherwise will make your transition to OpenTX much, much more difficult and confusing!

Ted

davidmc36 · Post by **davidmc36** » Tue Mar 18, 2014 1:13 pm

G550Ted wrote:With either a model or full scale, there is no way a fixed mix can accomplish the correct control inputs for any given crosswind except by chance.

Ted

Well, it's not as if you stop using ailerons just because you have some mix dialed in. It's just enough to stop it rolling over as soon as rudder is applied.

outdoors4evr · Post by **outdoors4evr** » Tue Mar 18, 2014 2:38 pm

I have a mix just like what JHSA first suggested with an inverted V curve. This is assigned to a flight mode named 'Knife' (not enough characters allowed for the 'edge').
It was a very simple to understand way to setup and did exactly what was needed. A little tuning on the percentage and I was all set. Also nice that I can turn it on and off with a switch.

gohsthb · Post by **gohsthb** » Tue Mar 18, 2014 11:04 pm

Looking through the posts here
Adjust weights as nessesary
Rudder to elevator mix, on elevator channel
+100% ELE
+50% RUD Curve(|x|) <invert weight if elevator moves wrong direction>

Rudder to aileron mix
aileron channel
+100% AIL
+50% RUD
other aileron channel
+100% AIL
-50% RUD
<notice no curve for the rudder. Again if the aileron movement is backwards then swap the weight + to - >
You can also add switches to the RUD mixes to enable/disable them too

To use a curve for the rudder to elevator mix
+100% ELE
+50% RUD Curve(c1)
c1 = 100 50 0 50 100
<same idea can be used on the aileron mixes>

-Gohst

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