Jump to content
AlexH

Taranis for sailplane use

Recommended Posts

AlexH    9

Am getting a bit frustrated trying to set up a full house sailplane and flight modes on a Taranis. Anyone have any good advice or links to "How To" guides?

Share this post


Link to post
Share on other sites
taurineman    10

I feel ya... When i got my Taranis, it frustrated the hell out of me - for every question, there are dozens of different answers. Such is the flexibility of the system, you have many ways of doing the same thing.

Have you checked out:

 

Maybe its best if you tell me specifically what you are trying to do, and i can help?

Mike Shellim has a ready-made F3J program:

http://rc-soar.com/opentx/setups/f3j/index.htm

also attached is my MaxaPro program

 

 

MaxaPro.eepe

Share this post


Link to post
Share on other sites
taurineman    10

I was there too, and i now feel im pretty much at the very top of the curve. So, im happy to try answer *any* questions anyone may have.

Share this post


Link to post
Share on other sites
AlexH    9

Usual full house sailplane mix with crow on throttle and three position switch with speed, clan and camber.

Do I SD card those into the transmitter?

Share this post


Link to post
Share on other sites
taurineman    10

The best way is to use CompanionTx to sync between PC and radio (both directions). In fact, i use CompanionTx to create/modify programs, not the transmitter itself. Sometimes i will need to do a tweak at the field, so i will do that on the TX, and sync back to the PC later.

So, you need a clearly defined workflow. Mine is:

  1. Sync from TX to PC using companion (becuase the TX is effectively the 'source of truth' and may contain field changes)
  2. Save the downloaded files from the TX to the PC filesystem and name it with the date in the name
  3. Edit the program as required/add sound files etc etc
  4. Sync back from PC to TX.

Other people i know who use OpenTX simply do everything on the TX and practically never use Companion. Again, its up to you. But i would recommend using Companion...

http://downloads-21.open-tx.org/companion/companion-windows-2.1.9.exe

I write something more about full-house program later....

 

 

 

Share this post


Link to post
Share on other sites
taurineman    10

so, if you download companion, you can open my MaxaPro program - which is basically copied and used for all my full-house task ships (F3b, F3J etc). I have the following flight modes:

  • 0 Distance (default)
  • 1 Launch (a logical switch triggers this mode for me, but a real switch works perfectly too)
  • 2 Landing (again a logical switch triggers this mode, but it can simply be a real switch)
  • 3 Speed (again a logical, but could easily be 
  • 4 Thermal (again a logical, but could easily be physical switch)

Each flight mode declares the following global variables (GVs) which are independent for all flight modes - eg FM1 AilDif is a different value to say FM1.

  • AilDif  - the amount of aileron differential, different per flight mode
  • AilRud - the amount of aileron to rudder coupling. Lots in launch, very little in Distance, more in Thermal, none in speed
  • Flaprn - the amount of aileron-flap mix, again different per flight mode
  • SnpFlA - The amount of snap-flap the aileron will move, again different per flight mode
  • SnpFlF - the amount of snap-flap the flap will move, again different per flight mode
  • FlpDif - the amount of differential for the flaps when operating as a flaperon, again different per flight mode

Each FM also carries its own fully independent trim values

Thats about it... The real sauce is in how the mixing is done, and how i use those GVs in mixes etc.

 

 

 

 

 

Share this post


Link to post
Share on other sites
taurineman    10

As for mixes, i found it easiest to think about it like:

  1. think of servo you want to move (and note channel number)
  2. add a mix line to that channel number
  3. set the mix line's input to the thing that i want to move that servo, set weights and offsets, and a switch to say when mix is active (or always active
  4. repeat...

so if you look at the attached image a CH04 (just ignore the CALIBRATE lines for now which i crossed out). You will see two lines grouped under CH04 (channel four on my RX is connected to the rudder servo).

  • The first line (one with most precedence) is getting its input from [I1]RUD (my rudder stick as set in the Inputs tab) with a 100% weight and is active in all modes; So in all flight modes there is a 100% correspondence between my rudder stick and the movement of my rudder servo - perfect!
  • The next line adds an additional mix. Its saying: "Oh and this other input can move the rudder servo too" and its [I4]AIL - eg when i move my aileron stick it also moves the rudder (eg an Ail->Rud mix) available in all flight modes; but its weight is set by the global variable GV2 (which is a different number in each flight mode); so in speed FM, its set to zero, so there is no Ail->Rud mix in speed mode. In each FM its a different number becuase i want different amounts of Ail->Rud mix in different flight modes.

 

So that mixing basics...

Go look at OpenTX university and invest some time digesting it all, and also open my program in Companion (it is a bit complex, but you should be able to follow the fundamental bits).

 

ele-rud_mix.PNG

Share this post


Link to post
Share on other sites
taurineman    10

So, ive been playing around with the concept of in-flight adjustable tripple rates. How many times have you built a plane to DS only to find that none of your pre-set tripple rates are just right in the groove? So, ive been playing around with a program on the companion simulator which allows you to adjust the ELE and AIL rates while you are in flight and they get remembered, so you dont need to re-set sliders or pots to some last known position.

Attached is the program. Its for a basic two-channel plank for now. So basically:

  • When Switch A (SA) is down, you are in rates-adjust mode. You can still fly, its just in this mode your ELE trim and your AIL trim wont do any trimming. If SA is mid or up, then its normal mode and all trims work normally.
  • When Switch A (SA) is down adjusting the ELE trim will adjust the elevator rate factor (and not elev trim); adjusting the AIL trim will adjust the aileron rate factor (and not ail trim)
  • SB is my elevator tripple rates switch (up=100%; Mid=75% x elev factor; Down=50% x elev factor)
  • SC is my Aileron tripple rates switch (up=100%; Mid=75% x aileron factor; Down=50% x aileron factor)

Dont forget to turn swtich A up to get regular trim working again.

So basically, in rates mode the trim switch increases or decreases the rate of that surface for Mid and Low rates. high rates will always be 100%. Easy enough to change so High rates is multiplied by the factor too.

What do we think?

 

 

 

 

 

 

 

variable_rates.eepe

Share this post


Link to post
Share on other sites
taurineman    10

I did but the slider solution won't remember where you find tuned it to. Next time you fly the slider will likely be in a diff position and your rates god knows where.

This one uses the digital trims, so positions are remembered and will be set to exactly the same position next time no matter what.

Share this post


Link to post
Share on other sites
taurineman    10

Hi Jono. Just got back from Fiji. Will post the scratcho program when I get home. It's my generic 6 servo f3x program.

I got an sr6 and have been playing with it. Think I've figured it all out now. Can post my trial program for it as well.

Share this post


Link to post
Share on other sites
taurineman    10

Attached is a EEPE file with both my Gyro'd Destiny program and my Scratcho program. I choose the Destiny cause it closely matches the S6R channels - eg 2 wing, single elev.  The S6R will only work with a two-servo wing im afraid. The S8R will do the 4 servo wing.

The Destiny program is my existing Destiny program with functionality to activate/control the gyro:

  • SD Up is no gyro
  • SD Mid is Stabilise Mode (eg rates mode)
  • SD Down is Auto-level mode (eg heading-hold)
  • RS adjusts the gyro gain from 0-100%

Ive not flown it with these settings to verify everything but it seems to be correct on the bench - use with a degree of caution.

 

GyroDestinyAndScratcho.eepe

Share this post


Link to post
Share on other sites
made_in_nz    7

I have read the opentx source code and think it is useful to know the "formula" used to calculate the servo output from what is configured in the input/mix/servo pages. To me it helps make sense of all the options. I've posted the pseudo-code to the opentx Facebook page so I'll dig it up and post it here too.

Share this post


Link to post
Share on other sites
taurineman    10
10 hours ago, made_in_nz said:

I have read the opentx source code and think it is useful to know the "formula" used to calculate the servo output from what is configured in the input/mix/servo pages. To me it helps make sense of all the options. I've posted the pseudo-code to the opentx Facebook page so I'll dig it up and post it here too.

Cool - yer, do that.

Mike Shellim has great info on his site:

http://www.rc-soar.com/opentx/basics/index.htm

 

 

Share this post


Link to post
Share on other sites
made_in_nz    7

So here was my question at the time:

I'm looking for a clear answer to a command chain question. I have read & watched pretty much everything I can find about this, but still have a few questions.
From www.rc-soar.com/opentx/ I learned that in opentx 2.0 the source > output formula for a mix changed from
(src + offset) * weight = output 
to
(src * weight) + offset = output

What about diff/expo/curves? Where in the input > ouput equation above do they fit? Before the weight is multiplied (ie src + (diff/expo/curve) * weight) + offset? 
I'm not even sure if diff, expo, and curves are applied in the same way in the formula.

I'd just like to know the formula, either written down, or in a diagram, so I can put pen to paper and figure out stuff rather than just guessing.

And here's what i discovered from reading the opentx mixer loop (mixer.cpp).  The formula (very much simplified) is:
v = source
v += trim
v = apply Curves to v (not diffential)
v = v * weight
v += offset
v = apply differential curve to v
output = v

In each line above the result of v is carried to the next line.

 

 

Share this post


Link to post
Share on other sites
taurineman    10

Mike mentions that Diff is applied after Trims - which leads to the "Differential Bug":

Quote

Diff works as expected, as long as the the trim is in the centre. However if you have some aileron trim applied, the following happens:

  • Diff is reversed on one side of stick centre, until the stick is moved enough to cancel the trim.
  • With the aileron stick at centre, altering the value of diff will cause one of the ailerons to move, thereby inducing an unwanted roll command.

Neither of these effects is desirable (though, interestingly, both

http://www.rc-soar.com/opentx/setups/diff/diff_bug.htm

On all my models i put the Trim on a seperate mixer line and remove it from the main control line (which has the diff) as per MIke Shellim

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×