Mixing it!

Mixing it!

Mixers in Ethos

Introduction

Ethos offers a comprehensive selection of mixers, all with a consistent interface. In this article, I'll provide details of the individual mixers, and their options. I'll focus on the glider mixers, however all the mixers work in a similar way.

Mixer categories

The glider mixers fall roughly into four categories:

Primary mixers
These mixers correspond to the main flight controls, and comprise Ailerons, Elevators and Rudders. The inputs are predetermined and cannot be altered. There are dedicated settings for rates, and the trim value is included in the output.
Secondary mixers
Mixers in this group are: Ail=>Rud, Ail=>Flaps, Rud=>Ail, Flaps=>Ele and Ele=>Camber. The inputs cannot be altered.
Tertiary mixers
Examples include Butterfly and Camber. With these mixers, you choose the input (stick, lever or knob). There is no option to included trims in the output.
Special mixes
These comprise VAR, FreeMix and Trim mixes.

Mixer parameters

The parameters used by the various mixers are shown in the table below:

Parameter Description
Input/source The stick, knob, switch etc. providing the input value to the mixer.
Active condition A condition (for example a physical or logical switch). For the mix to be enabled, the condition must be true. The default is 'always on'.
Flight modes List of flight modes. For the mix to be enabled, the active flight mode must be one of those listed. The default is 'all flight modes'.
Curve A curve (for example deadband or expo) which is applied to the input. The curve is applied before weight. With some mixes a list of curves may be specified, each associated with a condition. If more than one condition is true, the curve higher in the list wins.
Weight A percentage to multiply the input value (after any curve is applied). The value may be a constant or linked to a source/channel. A negative value reverses the effect of the mix.

For certain mixes, multiple weights may be specified, each associated with a condition. If more than one condition is true, the weight highest in the list wins.

With some mixers, there's a single weight field - the same weight is applied to all outputs. With other mixers, there's a separate weight for each output. There's no hard and fast rule, so read the mixer spec.
Offset A constant value which is added to the output (similar effect to a trim). In some mixes, the offset may be linked to a source/channel.
Differential Applies a differential curve to reduce the output in one direction. Applies to Ailerons and Elevators mixers only. The amount may can be derived from a separate source, providing a mechanism for in flight adjustment.
Channels count The number of destination channels.
Outputs The destination channels.
Reverse Reverses the sign of the output value.
Throttle Cut [TBC] Applies to Throttle mixer only.
Throttle Hold Sends the throttle to a user defined value. Applies to Throttle mixer only.
Low position trim [TBC] Applies to Throttle mixer only.

Mixer reference

Below is a list of the available sailplane mixers, colour coded by category.

Key:

Bold Value may be derived from a stick, logical switch or other source
abc Multiple values, each with condition
xyz Repeated field, one per channel

Ailerons

Active condition

Flight modes

Curve

Weight

Differential

Channels count

Output

Mixes the aileron stick to one or more channels, for roll control. The same weight is applied to all outputs, and for this reason, it's best for driving just one pair of surfaces (ailerons being the obvious choice!). For wings with four surfaces, create two mixes, one for each pair.

The trim value is included in the output.

This mixer is functionally identical to the Ail=>Flap mix - only the default output channels differ.

Elevators

Active condition

Flight modes

Curve

Weight

Differential

Channels count

Output

This mix is designed for the elevator function. The input is the elevator stick. The default output is the elevator channel(s). The trim value is included in the output.

Rudders

Active condition

Flight modes

Curve

Weight

Channels count

Output

This mix is designed for the rudder function. The input is the rudder stick. The default output is the rudder channel(s). The trim value is included in the output.

The relative direction of the outputs depends on the tail type, so remember to choose the correct tail type when creating the setup.

Ail=>Rud

Active condition

Flight modes

Curve

Channels count

Weight

Output

Aileron to rudder mix. The input is the aileron stick. The default output is the rudder channel(s).

Ail=>Flaps

Active condition

Flight modes

Curve

Weight

Differential

Channels count

Output

This mix is identical to the Ailerons mix except for the name, and the default outputs. Use the same way.

Rud=>Ail

Active condition

Flight modes

Curve

Channels count

Weight

Output

A rudder to aileron mix. The input is the rudder stick. The default output is the aileron channels.

Flaps=>Ele

Active condition

Flight modes

Input

Curve

Channels count

Weight

Output

This mix is useful for flap/camber/crow compensation, where a dedicated compensation curve is required. You choose the input. The default output is the elevator channel.

Ele=>Camber

Active condition

Flight modes

Input

Curve

Channels count

Weight

Output

Also known as 'snapflap'. You choose the input (normally be the elevator stick). The outputs will be the flap and optionally the aileron channels. Each output has an independently adjustable weight.

Butterfly

Active condition

Flight modes

Input

Curve

Channels count

Weight

Output

This mix is used for crow brakes. You choose the input (normally the throttle stick or a lever). The outputs will normally be the flap and aileron channels, and (optionally) the elevator channel for compensation. A curve will be needed to map the input to the range 0% – 100%. Each output has independently adjustable weight.

Camber

Active condition

Flight modes

Input

Curve

Channels count

Weight

Output

Functionally identical to the Butterfly mix. As the name suggests, it's intended to be used to apply camber to the wing surfaces.

Flaps

Active condition

Flight modes

Input

Curve

Channels count

Weight

Output

Flap mix. Functionally identical to the Butterfly and Camber mixers.

Throttle

Input

Throttle Cut

Throttle Hold

Flight modes

Curve

Weight

Low position trim

Channels count

Output

This mix is for motor control.

Var

Weight

Output

The VAR mix assigns a value to a channel. The value is supplied through the weight parameter.

Multiple weights may be specified, each associated with a condition. In the event of a conflict, the weight with the higher condition wins.

(The VAR mix is roughly equivalent to the GVAR in OpenTX. The main difference is that VAR values cannot be manipulated via special functions, and the values are not 'sticky' between sessions.)

FreeMix

Active condition

Flight modes

Source

Function type

Curve

Offset

Weight up

Weight down

Slow up

Slow down

Channels Count

Reverse

Output

A general purpose mix with flexible options. Use it to add functionality lacking in the standard mixers. An example is in-flight mix adjusters.

An entire setup can be created using free mixes, much in the style of OpenTX.

Trim

Active condition

Flight modes

Source for Up

Source for Down

Trim Mode

Extended Trims

Channels Count

Output

The Trim mix makes a control behave like a trim button. While the control is active, the output changes incrementally at set time intervals, just like a trim. There are separate inputs for up and down, however they will normally refer to the same physical control.