Programming a Mix for a Recoil Servo

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King Tiger Commander
King Tiger Commander
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Programming a Mix for a Recoil Servo

Post by phyrephish » Sat Apr 08, 2017 9:15 am

Hey All

Programming a mix for a recoil servo is one of the easiest mixes for your er9x/ersky9x/openTX radio. It is typically only a single mix that is added to whatever you use to trigger your main cannon. For this example I will create a mix for say a Tamiya or other MFU that uses CH3 (Ele) at 100% (full upstick) to trigger the cannon.

First up how do you trigger the main cannon? If you fire the cannon with a simple upstick movement then it is possible that no special mixes are in use. If you already have a physical switch to fire the cannon then programming the recoil is a little easier. For both cases the principal is the same - you will either use a switch either a physical or "logical" one to trigger the recoil action.

If you have a real radio then no doubt you are forever peeved with the aircraft terms. It seems that radio manufacturers are aware of planes only and no other remote controlled vehicles exist. In many cases Tankers find that we have to adapt features used for planes for use with tanks. Gun recoil is one of these things. The motion for gun recoil comes about as a modification of the feature designed to control the doors for landing gear. Doors typically have an opening time and a closing time. This is modded with recoil to provide an instant open (recoil back) followed by a slightly slower close (recoil forward to fire position).

Gun Fired with Stick:
In this case there is probably just the standard mix on your radio in which CH3 or ELE is assigned 100% to the elevation stick. In such a case the mix should look something like this.

CH03 +100% ELE

If the gun is set to fire with full stick then we want the recoil to be triggered when the stick gets to about +95%. To do this we can create a "Logical switch". So go to your Logical Switches Menu and setup a switch such that:

L.Switch 1 v>val Ele 95

This will mean the Logical switch 1 is activated when the Elevation stick goes higher than 95%. This is what we want to trigger the recoil so now let's set that up.

Go to your mixes section and select the channel that you want to connect your recoil servo to. I shall use Channel 8. Setup the following mix.

CH8 +100% FULL Switch (L1) slow (u0:d1)

Source: FULL - the channel will use the entire span -100 to +100
Weight: 100 - at rest servo is at NEGATIVE/CCW full extent (counter intuitive - it is only when mix is active that the channel goes to +100% or full positive/CW extent)
Switch: L1 - defines when the mix is on or active. In this case when Ele stick above 95%
slow (u0:d1) - this sets the action speed the servo such that it will move at max speed up to +100 and slightly slower back to -100%

Plug your recoil servo in CH8 and thats it..... Well you can then refine the action - maybe change speeds to suit and possibly the upper and lower limits of your servo travel (see your LIMITS Menu).

Pushing the Ele stick greater than 95% triggers L.Swith 1 which in turn triggers your recoil servo action on CH8.

Gun Fired with Switch:

If your Gun is fired with a switch then you will most likely have an additional mix on CH3

CH03 +100% ELE
+100% HALF Switch (TRN)

In this case flicking on the TRN switch gives +100% on CH3 (hence firing the cannon) - when off value returns to half way.

In this case all you need to do is add the CH8 mix for your recoil servo as given above replacing L.Switch1 with your physical TRN switch

CH8 +100% FULL Switch (TRN) slow (u0:d1)

Job done.....

Here is an example of the radio controlling the recoil servo solely


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