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TX programming terminology - what it means??


Old 01-08-2007, 10:42 AM
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Default TX programming terminology - what it means??

Hi all. I need some help.

I had to leave the RC hobby just as computer radios were coming into use so I had no exposure to them or the terminology used.

Now that I'm back into the hobby my TX of course needs to be programmed. I am computer literate so I'm not afraid to jump in and start programming the thing. My problem is that I don't know what they are talking about when talk about things such as mixing for example. What is mixing for, etc?

My question is this, is there a web site that you know of that explains the terminology used in TX programming?

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Old 01-09-2007, 09:21 AM
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Default RE: TX programming terminology - what it means??

> things such as mixing for example. What is mixing for, etc? <

Mixing allows one channel to control a second channel simultaneously. For example, those of us who are too clumsy to smoothly operate a rudder with the left hand while using the ailerons with the right hand can set the rudder channel as a slave to the aileron's master channel. With high climbing RC-assist old timers I have programmed some down elevator when the throttle is wide open to moderate the climb angle.
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Old 01-09-2007, 05:11 PM
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Default RE: TX programming terminology - what it means??

The best source of information on this is from Ed Anderson (aeajr). This guy is GREAT! He writes clearly and explains fully. Below is one of his threads - I downloaded it to my reference file but didn't include the link (BOO). To ED - Trust me, the credit IS ALL YOURS - & THANKS FOR IT!

You are out looking for your first radio, an upgrade radio, you are reading ads and boxes and there are all these terms you don't understand. Something about mixing. Do you need that? Maybe, maybe not, but it would be good if you understood the terms. Here is a short discussion on surface/channel mixes. This occurs when more than one control surface is moved by a single input from your radio. I will only touch a few, but you will get the idea. I invite others to clarify or correct my comments and add where these mixes, or others, are used.

First, there are three primary control surfaces:

Elevator - Pitch or attitude control - nose up and down - usually part of
the tail

Rudder - Yaw control - nose left and right - usually part of the tail. On a
plane without ailerons, the rudder can work with dihedral in the wings to
roll the plane to effect turns.

Aileron - Roll Control - usually on the trailing edge and outer aspect of
the wings, though ailerons can extend the full length of hte wings in
aerobatic planes.

There are two secondary control surfaces, usually used in landing.

Flaps - These are a moveable part of the trailing edge of the wing that you
lower to slow a plane while adding lift to the wing and lowering the stall

Spoilers - Typically used in landing gliders or sailplanes, these are on the
top of the wing. When these are raised, they reduce, or spoil the lift of
wing in that area. They can help slow a plane down and raise the stall
of the plane causing it to descend from lack of wing lift. These can also
helpful in getting sailplanes out of strong thermals.


These two use two surfaces that are coordinated to create the function that
are typically performed by separate surfaces. When we move two of these
surfaces toghether we call that surface mixing.

V-Tail mix - comes from the fact that on a V-tail plane, you do not have a
separate elevator and rudder. The two V surfaces are mixed to perform these
functions. If you hit up elevator, both move up. If you hit right rudder
AT THE SAME TIME as up elevator, the tail surfaces move some more moving the
nose to the right as it moves up. So you have mixed the rudder in with the
elevator input. V-tail mixing. For this reason, the surfaces on a v-tail
plane are called rudervators; rudder/elevators

Elevon or Delta Mixing - Typically used on a flying wing, like the Zagis,
delta wing, like my Electrajet. They combine the function of elevator for
pitch, and ailerons for roll. This is elevator/aileron mixing. The
surfaces are referred to as elevons when they are used in this way adn are
usually located at the back of the plane.

Many of the newer non-computer radios include v-tail and elevon mixing
whereas it used to require a computer radio, or the addition of a special
mixing device in the electronics package. Many of hte low cost RTF 3
channel planes incorporate mixing in their design. For example the Aerobird
uses V-tail mixing. The F27 Stryker uses elevon mixing.


Note that none of these mixes are required to fly a plane

using a computer radio you can coordinate all types of combinations for
different effects. Some can be turned on during the flight. Flip a switch
and you will get a different behavior from the control surfaces for the same
stick input. I will use the convention of master/slave where one surface
gets the input and the other follows. For example, aileron/rudder would
imply that you input aileron control and the rudder follows without you
touching the rudder stick. While you can do this manually, some of these
mixes would be would be very hard to do by hand, and some can ONLY be done
from a computer radio. Many of these mixes require radios with 6-8 channels
and some require the radio be able to address 4 servos in the wings
independently, a feature of higher end radios.

Aileron/rudder mix - Coordinated Turn - On power planes and on sailplanes,
it is normal to add rudder to aileron input. This is called a coordinated
turn and is common to do manually on non-computer radios, but computer
radios can be set up to do this automatically. This results in a smoother,
more efficent turn.

Flapperons - Ailerons can act as flaps, used if you don't have flaps, for
landing control. These are known as flapperons which is a change in assignment of the surface from aileron behavior to flap behavior. This requires two servos for the ailerons.

Flapperons - flaps act like ailerons. Found this idea being used on a R/E
Flap sailplane. If you hit this link and read from post 49, you can see how
this is used. Interesting idea.

Differential Spoilers - You can take spoilers, at the top of the wings, and
tie them to the aileron function. Now you have your spoilers at different
heights causing a roll effect. Not as effective as ailerons, but it could
enhance the roll of a plane that does not have ailerons. To do this your
spoilers require two servos instead of one and they must be controlled from
separate channels. This would require at least a 5 channel radio..

Elevator/flaps - snap flaps - This is used in aerobatics or racing to effect
very very fast turns or very tight loops. When you pull elevator, the
elevator goes up and the flaps go down causing a change in pitch AND an
increase in lift in the wing. The plane will turn very tightly.
Careful, this can lead to a stall if you don't have enough speed but in the
typical application, this is done at high speeds, or in planes that have
very powerful motors.

Aileron/flaps - You can add the flaps to the ailerons so that the flaps move
with, and coordinate with the ailerons The flaps become extensions of the
ailerons for more control surface movement. This takes 4 wing servos, and
they must each be controlled from a separate channel on your radio. This
requires at least a 6 channel computer radio. Only more advanced radios can
do this. Likewise, the ailerons can be made to follow the flaps to multiply
the effect of lowering flaps. This requires a minimum of three servos, two
on the ailerons and one on the flaps.

Ailevator - on aerobatic or pattern planes they will split the elevator so
that two servos operate each half. Normally they move together to create
the normal elevator motion. However when you enable the ailervator mix, the
elevator halves will move with input from the ailerons causeing the plane to
roll much more quickly. This requires the two elevator servos to be
controlled from separate channels on the radio. Typically this requries a 7
or 8 channel radio.

Snap Roll - this is a mix that actually moves surfaces during a roll to
create a highly coordinated and highly repeatable type of aerobatic
manauver. Ailerons and rudder will be controlled. Elevator is likely to be
programmed in as well. I have never used this one, but it sounds cool!

Camber Changing Trailing Edge - Typically used on sailplanes, they use a mix
where the ailerons and flaps move together, typicaly not from one of the
sticks, but from a switch or dial. By moving them slightly up or down,
perhaps 1/16", you change the shape of the wing while it is flying. By
lowering the flaps and ailerons together you create a more under cambered
wing which generates more lift, but typically more drag. If you move
them up slightly, then it is called reflex. A minimum of three wing servos
is needed to do this. I don't know if this is used on power planes.

Crow, Butterfly or Airbrakes - Commonly used on sailplanes, this is a
breaking mix used to quickly slow the plane, often in contest flying where
you need a very precise landing. Both ailerons go up while the flaps go
down. Often there is some elevator mixed in to keep the plane level. This
would take at least a 6 channel radio that can take the coordination of as
many as 6 servos controled by one stick, lever, dial or switch.

Flight Conditions - Essentially this moves surfaces to a new trim position
based on some flight situation. It could be take-off or landing, or it
could be some point in an aerobatic routine. It might be a sailplane
circling in a thermal. Whatever it is, it establishies a new trim point for
the surfaces when there is no stick input. On my gliders, on winch
launching, I flip launch mode or launch condition and the ailerons droop 15%
and the flaps droop 25% to give me more lift during launch.

Imagine the fun you can have changing between different launch modes, or
moving from launch to standard flight mode to several enhanced flight modes,
to a camber change to 3 different landing modes.

Well, this is one of the values of computer radios. Not all computer radios
can do all of these mixes and there are other mixes not mentioned here.
However when you read the spec sheets, they will usually list Airplane
Mixes, perhaps Sailplane Mixes and some also do Helicopter Mixes.

You will also hear about mode 1 and mode 2. In North America, Mode 2 is the
standard. More on modes can be found here.
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Old 01-10-2007, 05:24 AM
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Default RE: TX programming terminology - what it means??

The best thing for me about mixing is that you can make your rudder more user friendly if it has a tendency to role and pitch while using it. If your model have some of these bad habits you must now try to mix them out. Reverse ailerons mixed with rudder will cancel any rolling tendencies, ad elevator mix if it has a tendency to pitch. The goal of this exercise is to get your plane to do flat turns, with minimum input from you except rudder. Once you have done this, you will feel much more at ease when using your rudder. You will discover how handy this device can be to correct heading when approaching for landing, stall turns and wing overs will also look better. Remember although your rudder is now more user friendly it will still have a braking effect on the plane when you use it, so don’t let your airspeed go too low. This can be put to good use though, if you doing a landing approach and notice that your airspeed is too high do a few zigzags with your rudder to slow it down. Also Flying a knife edge will be much easer.

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Old 01-10-2007, 08:26 AM
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Default RE: TX programming terminology - what it means??

Dsegal, Wheels13 and Piet Le Roux, thank you all for the information. Wheels13, I've added your information to My Favorites so that I can refer back to it as needed.

Thanks again,
Larry (Birman)
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