Taranis/Horus/OpenTX radio mods and programming for F3X/ TD - RC Groups
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Mar 04, 2017, 08:05 AM
Registered Taranis User
Miami Mike's Avatar
Discussion

Taranis/Horus/OpenTX radio mods and programming for F3X/ TD


For quite a while I've been following the Taranis and OpenTX threads on the Radios forum, but RCGroups has allowed those threads to grow into huge mazes of posts about all sorts of models, with the subjects constantly changing from one post to the next. They've become virtually worthless to someone seeking help or offering advice specifically related to sailplanes, so my hope is that a thread here in the F3X forum will catch on and be more useful to those of us who are almost exclusively concerned about programming and modifying OpenTX radios like the Taranis to control F3X or TD gliders.

I'll start the thread with a plug for my Glider Simulator Lua script, which was a project that started out to be a fun little toy but has turned out to be an extremely useful tool for developing and testing glider setups. It's free, of course. Just grab it from my blog, follow the instructions, and post any questions or comments either here or on my blog.

Of course I hope this thread will develop into much more than that, but it's a start.
Last edited by Miami Mike; Mar 04, 2017 at 06:34 PM.
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Mar 04, 2017, 08:37 AM
Aussie F3K Team
A general question about receivers, servos, rssi and antenas in open thermal ships. I have used Taranis in dlgs for a while, but not the big stuff.
1. Do i need the optional 'long range' Rx antenas (with the mouldings on the end) or are std ones ok.
2. Is the any difference in the D or X series receivers.
3. Where should i place my rx antenas? Next to my battery or next to my servos or one near each?
4. Are there any servos that frsky jitters with?
5. Can i drop the RSSI warnings to 40 and 38, given we are flying at such long distances?
Anything else setup wise to recommend?
Thanks in advance.
Marcus
Mar 04, 2017, 08:46 AM
Aussie F3K Team
Im also interested in developing a vario sink rate readout that averages the sink rate over a 10 second period to even out minor disturbences that make the instant reading continually jump up and down. I found this feature usefull in my (now retired) Graupner MX-20 to tune my dead air times ( when calm and windy) quickly.
Any thoughs?
Marcus
Mar 04, 2017, 11:26 AM
F3B
satinet's Avatar
Quote:
Originally Posted by Machineman
A general question about receivers, servos, rssi and antenas in open thermal ships. I have used Taranis in dlgs for a while, but not the big stuff.
1. Do i need the optional 'long range' Rx antenas (with the mouldings on the end) or are std ones ok.
2. Is the any difference in the D or X series receivers.
3. Where should i place my rx antenas? Next to my battery or next to my servos or one near each?
4. Are there any servos that frsky jitters with?
5. Can i drop the RSSI warnings to 40 and 38, given we are flying at such long distances?
Anything else setup wise to recommend?
Thanks in advance.
Marcus
1) i flew the normal ones in f3b ok. But this was pre the eu protocol. Not relevant if you are in the usa
2) x recievers use plug in smart port telemetry sensors. D mode dont. Not sure either is better range wise.
3) not as such see 4
4) the rx aerials cause jittering if placed close to some servos. But that's not frsky specific. I had the same issue on hitec. E.g the mks 6125e.
5) you can adjust the rssi warning. I used to get a few in f3b duration
Mar 04, 2017, 11:28 AM
F3B
satinet's Avatar
The big problem for f3x with opentx is that flight modes are not good. The global variable system isn't good imho. Has it uses but it's no alternative to flight mode specific settings. Yeah you can turn inputs and outputs on or off in different modes but it's very clunky.
Mar 04, 2017, 04:28 PM
Registered Taranis User
Miami Mike's Avatar
Quote:
Originally Posted by satinet
The big problem for f3x with opentx is that flight modes are not good. The global variable system isn't good imho. Has it uses but it's no alternative to flight mode specific settings. Yeah you can turn inputs and outputs on or off in different modes but it's very clunky.
What do you mean by "flight mode specific settings"? If you mean trims, each trim can be set to "Own Trim", "Use trim from Flight Mode (x)", or even "Use trim from Flight Mode (x) with Own Trim as offset." A trim can store up to 9 separate values, one for each flight mode.

And the trims can be re-purposed to serve a variety of functions, including adjusting switch-selected global variables. My current setup uses the throttle trim to set elevator position for Kapow, elevator compensation for Flap mode, elevator compensation for Crow mode, Launch camber, Zoom reflex, Thermal camber, Speed reflex, and the flap position in a special flight mode I have for setting failsafe positions.

My rudder trim can be set with another switch to adjust aileron-to-rudder mix, aileron differential, or, of course, rudder trim.

Global variables work the same way, and with 9 flight modes and 9 global variables, you can store up to 81 different values.

What exactly are these flight mode specific settings that are missing?
Mar 04, 2017, 05:55 PM
Registered User
Quote:
Originally Posted by satinet
The big problem for f3x with opentx is that flight modes are not good. The global variable system isn't good imho. Has it uses but it's no alternative to flight mode specific settings. Yeah you can turn inputs and outputs on or off in different modes but it's very clunky.
Why are flight modes not good? You actually get 9 flight modes which is more than a lot of other radios.

Also global variables is one of the most powerful and flexible things about opentx.
Mar 05, 2017, 01:53 AM
F3B
satinet's Avatar
My radio has got 10 flight modes and you can change every single setting for each flight mode. And there is a screen where you can trim each servo for each flight mode. I.e for camber.

On a good radio you can alter virtually any setting in any flight mode.

If you want to have different elevator travel, camber, differential, aileron to flap, expo, aileron travel etc etc etc you will soon run out of global variables and will have to start turning mixes on/ off. On a different screen. Some in the mixes menu some in the inputs menu.

Camber settings are a pita in open tx because you can't have a setting for each servo. When you get a misalignment it's hard to resolve. Which happens on models with lds or rds.

I know how global variables work and how to programme the radio. I've still got a taranis and i use it for some models but not for f3b.
Mar 05, 2017, 06:59 AM
I don't want to "Switch Now"
pmackenzie's Avatar
In Opentx camber can be adjusted without going into any screens at all, just using the throttle trim.
I do use a gvar, since I have flap and aileron camber separate, but this only uses one of them. But the adjustment is still made without going into any screens.
Mar 05, 2017, 07:17 AM
Registered User
The example I always give, even to Opentx "experts" is 2+2 =4 and so does 3+1 and even 5-1. I don't want to turn this into an Opentx lesson but almost all your statements in post #8 are user problems.

Does that makes sense?

Any line in inputs or mixer can be flight mode dependent.

If you use GVAR you should normally reserve those for inflight adjustments first and then flight mode dependent "hard" values so you don't run out.

If you run out of GVAR you can just add lines in the mixer.

I have a couple LDS models and if the wing does not have perfect symmetry then you can apply a custom curve in the output screen OR you can just write an individual line in the mixer for each surface.

Do you use Jeti? I use Jeti as well and it's not remotely the same at all. Jeti is a pretty traditional menu based template operating system. If you are an advanced user in OTX you can pretty easily match and surpass all the features of Jeti.
Mar 05, 2017, 07:38 AM
Registered User
mikeshellim's Avatar
Quote:
Originally Posted by satinet
My radio has got 10 flight modes and you can change every single setting for each flight mode. And there is a screen where you can trim each servo for each flight mode. I.e for camber.
Why would you need to do that if the servos are correctly calibrated?

Or put another way, if my model is already perfectly symmetrical, why would I want to make it unsymmetrical?

Quote:
If you want to have different elevator travel, camber, differential, aileron to flap, expo, aileron travel etc etc etc you will soon run out of global variables and will have to start turning mixes on/ off. On a different screen. Some in the mixes menu some in the inputs menu.
You're conflating a number of different issues. As regards GVAR's, these are not the only way of adjusting mixes - trims and spare knobs can also be used, with the advantage of providing instant feedback to the pilot. GVARs and trims are flight mode aware, so the number of flight modes is irrelevant.

The nine GVARs provided are sufficient for most setups (including both my F5J setups).

Quote:
When you get a misalignment it's hard to resolve. Which happens on models with lds or rds.
Not necessarily so.

With a decently structured template, linkage misalignment is easily dealt by re-calibrating the affected servo. Each servo may be assigned a curve with between 2 or 17 points. You can tailor your own 'CAL' mode to ease the calibration process. For example I have both ailerons move up together so I can balance their movement by eye.

So in answer: fixing a bent linkage is simple - switch to CAL mode, re-cal the servo, and fly. One minutes work at most.

Quote:
I know how global variables work and how to programme the radio. I've still got a taranis and i use it for some models but not for f3b.
I don't think you've programmed it efficiently.
Mar 05, 2017, 01:21 PM
F3B
satinet's Avatar
The issue with Gvars and mixer lines is that you have certain settings you always adjust. e.g

aileron travel
f->A travel
aileron differential
f->a differential
camber
elevator travel
rudder travel
rudder differential
snap flap volume
etc
before you even talk about different curves etc.

Yeah you can can add new mixer lines. But there is also a limit on the mixers which you can hit with a complex setup. It takes a lot of scrolling through to find the setting you want, especially if you are using "high mixes", which you might be for stuff like snap flap. Oh and you have to give each mix a meaningful name in the 8 characters (or whatever it is), with the slow, clunky user interface (to be fair the taranis is largely responsible for the horrible chore of actually entering stuff - the x9e with it's scroll wheel was very different).

I concede the input screen has been improved. But if you have got say 8 flight modes and lots of settings it just becomes a pain to manage it all on open TX. There too much chance of a mistake in the stress of a contest. It's really ends up in a complex mess and I and can't really get on board with people denying it.

Flight modes are not good? Come on you can't even move the flight modes around with out a major headache. Trying putting a new flight mode in above your existing modes and see where it gets you. Have fun going through every mixer line. Change the priority of the existing flight modes........

I don't come from the position of being mind-blown by opentx. I had a multiplex p4000 for a good few years and the programming on that, which pre-dates opentx by many years, was pretty much the same. Yeah it was super flexible but like anything there are pros and cons. As with the p4000, the evangelists - I used to be one - don't twig when they get beaten by people with a "worse" radio. The radio doesn't make that much difference even if it's better. Having a radio that you can make adjustments on easily mid contest , or mid flying session is more useful that being able to play la cucaracha when your plane goes over 500ft.

I've been saying for ages that opentx would be a far better glider radio if it had a flight mode trim screen like jeti, but all you ever hear is how you don't understand (the religion) properly. No doubt I'll be told I just don't get it..........

Anyway - sorry for taking the thread away from it's original direction.
Mar 05, 2017, 05:01 PM
Registered User
mpjf01's Avatar
Quote:
Originally Posted by Machineman
A general question about receivers, servos, rssi and antenas in open thermal ships. I have used Taranis in dlgs for a while, but not the big stuff.
1. Do i need the optional 'long range' Rx antenas (with the mouldings on the end) or are std ones ok.
2. Is the any difference in the D or X series receivers.
3. Where should i place my rx antenas? Next to my battery or next to my servos or one near each?
4. Are there any servos that frsky jitters with?
5. Can i drop the RSSI warnings to 40 and 38, given we are flying at such long distances?
Anything else setup wise to recommend?
Thanks in advance.
Marcus
The whisker antennas are OK, there's really nowhere to put the PCB version in a current F3J type glider. FRSKY makes antenna extensions for its receivers purchased more than a few months ago (those with the more robust thicker coax) and these allow the active elements to be repositioned to, say, behind the wings if desired. They also give marginally better range.

D receivers consistently give higher RSSI readings and slightly better range than X series in my experience. The L9R is better again but only comes with PCB antennae and no telemetry. There's discussion here

https://www.rcgroups.com/forums/show...ng-Information

As a system operating correctly will give more range than is useful the main "benefit" of D series is fewer of the annoying low RSSI warnings

I try to put the whiskers outside the fuselage. In a "2.4 friendly" fuselage it's common to see one of the antenna oriented vertically in a tube between the RX and servos and another in a tube running fore-aft against the fuselage side next to the servos.

The advent of the RX8R allows the use of a second SBUS receiver in a diversity arrangement for anyone concerned about range issues. I would leave it for a time until FRSKY gets the diversity component of the firmware on that receiver perfected though.

It's not uncommon to get lots of low and critical RSSI warnings during a flight as antennas become occluded at certain orientations, eg when circling in thermals. The logs will show the actual values at the logged intervals and I often see RSSI values of zero for one or more cycles. This means that telemetry data is not being received of course, not that control is lost. The range test data in the thread linked above shows that control is maintained at far greater ranges than the telemetry signal. Nevertheless the warnings can be annoying and many users do lower the warning thresholds to minimise them.
Mar 05, 2017, 06:50 PM
Registered User
mikeshellim's Avatar
Quote:
Originally Posted by satinet
if you have got say 8 flight modes and lots of settings it just becomes a pain to manage it all on open TX. There too much chance of a mistake in the stress of a contest. It's really ends up in a complex mess and I and can't really get on board with people denying it.
[...]
I've been saying for ages that opentx would be a far better glider radio if it had a flight mode trim screen like jeti,
Attached screen shots which show all the day to day adjustments on my Needle 115 - look, no Mixers menu!

The four key mixes (diff, snapflap volume, snapflap expo and crow compensation) are adjusted directly from the transmitter using spare trims and knobs, so there is little scope for error during a competition.

BTW I really dont get this 'flight mode trim' thingie on the Jeti. What happens if you replace a servo... do you then have to do a grand tour of all the flight modes, tweaking all these 'trim' adjustments? And what if you have some trim dialed in, how do you distinguish that from shifts due to bent linkages/drifting servos?
Last edited by mikeshellim; Mar 05, 2017 at 07:03 PM.
Mar 06, 2017, 12:09 AM
Registered User
Aaro's Avatar
Nothing happens as long as you replace the servo with similar one. Maybe a few % from subtrim in case the spline/gear is different orientation. No need to touch the FM trim.

Aaro

Quote:
Originally Posted by mikeshellim
BTW I really dont get this 'flight mode trim' thingie on the Jeti. What happens if you replace a servo... do you then have to do a grand tour of all the flight modes, tweaking all these 'trim' adjustments?


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