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Mixing
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Aside from your choice of aircraft, mixing can give you the greatest improvement in your flying. A lot of people get a glazed look in their eyes when you talk about mixing, though. I used to be one of them. I had my first computer radio for 10 years before I realized the power of the programmed mix. Once you understand it, mixing opens a whole world of possibilities. Let’s talk a little about why mixing is so helpful.

First, without exception, every plane has some form of control coupling. What that means is, when you move one control, it will have an unwanted affect on another control axis. For example, if you hit left rudder, every plane also tries to roll left. So, when you roll to a knife edge and add rudder to hold it, the plane tries to roll back to level. You counter by adding opposite aileron to hold the knife edge…so now you are adjusting rudder AND aileron to fly straight. And most planes have an elevator coupling too, so now you are holding three separate control inputs, just to fly straight and level in knife edge. If this is the way you are flying, you are not winning any contests! We can mix those controls so that all you have to do is roll into the knife edge and add rudder. That’s it…it flies straight! Here’s how we do it.

Radio Mixing Basics

Everybody always asks if the mixes should be placed on a switch, so you can turn them off. The answer is definitely not. If the plane needs the mix to begin with, it needs it all the time. You don’t need the possibility of forgetting to hit a switch to mess up a sequence…and , if you’re like me, you will forget which switch it is on anyway. Set the mixes up, activate them, and forget about them.

Radios have some mixes ready to go, like rudder to aileron. These “canned” mixes have only one point to program for each direction of stick motion, which is good, if pattern is all you fly. With the small control deflections we use in pattern, the coupling is linear, and that is what a canned mix gives you…linear mix. The bad news, though, is if you plan to do 3D, the plane does not behave linearly with large control deflections. The aero guys call this divergence, and all planes experience it at 3D control rates. The good radios have what they call “curve”, or “multipoint” mixes to fix this problem. I really recommend these radios to anyone serious about 3D.

So, let’s bring it all back to earth. If all you are ever going to do is fly pattern, a single point mix is just fine. If you ever think you might want to fly 3D with the plane, then use a multi-point mix. It’s that simple.

The next confusing part is linking. If you are running two elevator servos, you are most certainly using a mix from the elevator to the second channel for the opposing elevator half. If you want to mix rudder into both elevator halves, you use the link function to send the mix to the second channel. That way you don’t have to use another mix to do the same thing. It’s pretty cool, but can be tricky. Some of the manufacturers neglect to tell you that linking is not available on all of their channels. You often have to figure this out the hard way…by trying and failing a few times.

Now let’s go through the steps of setting the mixes for a pattern plane. Each step includes a test to see if your particular plane needs a particular mix. Most planes will not need all of the mixes, but some will. I will cover only pattern here. Following the basic pattern mixes, I will include a section on how to go about setting mixes for 3D.

Rudder Mixes

Throttle Mixes

Aileron Differential

 
 

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