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OpenTX Question

buzzbomb

I know nothing!
#1
Firstly, props to the developers who are making it happen and the Family members who recommended it to me. I've read enough to realize I can do just about anything RC, with the trans and software. I can build whatever I want.

I could build a TinyTrainer, give it a V-Tail and program everything so that I've got a little bit of this and and a little bit of that and make it fly as something it was never intended to be. I've got a trans with a whole lot of channels and switches just waiting for me to program them. I can literally make any switch or input or output do anything I want. That's pretty darn strong. It's also, and I kid you not, a STEEP learning curve.

I knew that before I bought it. I was warned and also encouraged. My whole flying style is getting out there and getting stupid. It's stress relief. A few years down the road? My Gosh, if you haven't read into OpenTX, you have no frackin' idea of the possibilities.

That being said. It IS a steep learning curve. My question? I'm short of motors and I want put my TT into the air as 4-channel with the F motor. Assuming I can get her to balance with my 3s battery, I don't want to crash because I can't control the speed. I'm all about crashing foamboard planes, ya'll know that, but I want to fly! Holy Shoot! She'll be be absolutely glorious!

I've never successfully flown 4ch and I want to maximize my chances of success. I would like to limit the maximum thrust that I can give to the F motor. I remember there is a screen where you set min and max limits, but I don't understand how it actually works.

If anyone can offer up some insight, I would be much appreciated. Otherwise? My usual 100% all the way, baby! :D
 
Last edited:

CarolineTyler

Well-known member
#2
Firstly, props to the developers who are making it happen and the Family members who recommended it to me. I've read enough to realize I can do just about anything RC, with the trans and software. I can build whatever I want.

I could build a TinyTrainer, give it a V-Tail and program everything so that I've got a little bit of this and and a little bit of that and make it fly as something it was never intended to be. I've got a trans with a whole lot of channels and switches just waiting for me to program them. I can literally make any switch or input or output do anything I want. That's pretty darn strong. It's also, and I kid you not, a STEEP learning curve.

I knew that before I bought it. I was warned and also encouraged. My whole flying style is getting out there and getting stupid. It's stress relief. A few years down the road? My Gosh, if you haven't read into OpenTX, you have no frackin' idea of the possibilities.

That being said. It IS a steep learning curve. My question? I'me short of motors and I want put my TT into the air as 4-channel with the F motor. Assuming I can get her to balance with my 3s battery, I don't want to crash because I can't control the speed. I'm all about crashing foamboard planes, ya'll know that, but I want to fly! Holy Shoot! She'll be be absolutely glorious!

I've never successfully flown 4ch and I want to maximize my chances of success. I would like to limit the maximum thrust that I can give to the F motor. I remember there is a screen where you set min and max limits, but I don't understand how it actually works.

If anyone can offer up some insight, I would be much appreciated. Otherwise? My usual 100% all the way, baby! :D
Sounds like to need to reduce your throttle endpoint to say 80 to 85%.
http://open-txu.org/home/undergraduate-courses/basic-airplane-set-up-with-taranis-2/servos-713/
https://oscarliang.com/reduce-power-throttle-taranis-betaflight/#mixer-weight
 
#3
One main thing to note is that mixes should never be confused with inputs. Make sure you are using the input page before you start. I would recommend reducing the throttle only slightly, to around 90%, but adding around 20% expo to that. That way, you can still gain speed quickly if you are about to go into a stall. I would also recommend turning down the ailerons to around 75%, as that tends to be the main issue that arises with semi-fast planes. Less deflection gives you less torque.
 

buzzbomb

I know nothing!
#4
Thank you both for your replies. @CarolineTyler I'm going to read those pages, when next I revisit programming the new trans. It's one thing to say it can do everything. I've got to actually make it do everything. I recognize that. Those will be invaluable resources. Thank you.

@Spacefarer Yes. There's where I am confused. There is a pathway that is recommended, but it goes into actual programming. If this, then that. That's where I got lost. I would love to throw expos and whatnot into the mix, I just haven't figured out how, and I've GOTTA fly! My bones are aching for that stress relief!

I'll continue to muddle through the learning curve, in the meantime, I've solved my problem. The 4-ch TT will be flying with the A-Pack. I'll put the F-Pack into the my newly resurrected Tora Tanshi, 3-ch TT! They'll both be a blast! I've got three planes almost ready to fly on two transmitters. They're missing PowerPods and CG balancing. That's it. I may be 100% all the way, but heck. What's the worse that can happen? I crash? :LOL:
 

evranch

Active member
#5
You don't have to use the logical switches (IF/AND/OR etc) to set up something like a rate limit or expo. It can all be done on the mixer screen.

Expo is easy.
- Pick the channel you want to add expo to on the mixer screen, and long press Enter. Choose "Edit".
- You will see a line for "Curve" that probably says "Curve Diff 0".
- Select "Diff" and press Enter. You can change it with +/- to "Expo". Press Enter.
- Now select the number beside it, probably 0, and press Enter. You can change it with +/- to the amount of expo that you want. Press Enter.
- Press Exit, you are done!

Dual rates with a switch is a bit more challenging but doesn't require any logical switching again.
I won't type this button press by button press because after setting up your expo you should be familiar enough with the interface.

- Pick the channel you want to add dual rates to and long press Enter. Choose "Insert After"
- Set the source to MAX
- Set the weight to what you want to multiply the rate by. So if you want the max throttle to be 80%, set it to 80.
- The little bar should now show -80 and 80 at the endpoints.
- Choose "Switch" and flip the switch you want to use into the position where the rate will be limited. It will show up automatically. This binds the switch to the mix. You can bind as many different mixes to the same switch as you want.
- Keep going down to "Multiplex" and change this to "Multiply"

What you have done is set up a mix with a constant of 80%. When the switch is flipped, it will activate the mix and multiply your current input value by that constant, limiting your rate. The reason it is inserted after is because the mixer program executes each line in sequence. A lot of mix mistakes happen because of the order of the lines.

- Press Exit and look at the line you have created. Flip the switch on and off and see if the number shown flashes from regular to bold with the switch.
- Hold your throttle to max (obviously your receiver is not powered up...) and look at the little bar at the top. Does it read 100? Now flip the switch. It should drop to 80.

Once you get the hang of how it works you will be correcting thrustline issues by mixing elevator with throttle in no time, or setting up triple rates, flaperons, or extra expo for landing that comes on when you drop the gear. The potential is limitless!
 

buzzbomb

I know nothing!
#6
You don't have to use the logical switches (IF/AND/OR etc) to set up something like a rate limit or expo. It can all be done on the mixer screen.

Expo is easy.
- Pick the channel you want to add expo to on the mixer screen, and long press Enter. Choose "Edit".
- You will see a line for "Curve" that probably says "Curve Diff 0".
- Select "Diff" and press Enter. You can change it with +/- to "Expo". Press Enter.
- Now select the number beside it, probably 0, and press Enter. You can change it with +/- to the amount of expo that you want. Press Enter.
- Press Exit, you are done!

Dual rates with a switch is a bit more challenging but doesn't require any logical switching again.
I won't type this button press by button press because after setting up your expo you should be familiar enough with the interface.

- Pick the channel you want to add dual rates to and long press Enter. Choose "Insert After"
- Set the source to MAX
- Set the weight to what you want to multiply the rate by. So if you want the max throttle to be 80%, set it to 80.
- The little bar should now show -80 and 80 at the endpoints.
- Choose "Switch" and flip the switch you want to use into the position where the rate will be limited. It will show up automatically. This binds the switch to the mix. You can bind as many different mixes to the same switch as you want.
- Keep going down to "Multiplex" and change this to "Multiply"

What you have done is set up a mix with a constant of 80%. When the switch is flipped, it will activate the mix and multiply your current input value by that constant, limiting your rate. The reason it is inserted after is because the mixer program executes each line in sequence. A lot of mix mistakes happen because of the order of the lines.

- Press Exit and look at the line you have created. Flip the switch on and off and see if the number shown flashes from regular to bold with the switch.
- Hold your throttle to max (obviously your receiver is not powered up...) and look at the little bar at the top. Does it read 100? Now flip the switch. It should drop to 80.

Once you get the hang of how it works you will be correcting thrustline issues by mixing elevator with throttle in no time, or setting up triple rates, flaperons, or extra expo for landing that comes on when you drop the gear. The potential is limitless!
YOU Sir, seriously ROCK! Wow. I've read enough to realize what the system is capable of. I was seriously impressed. You've just helped me learn to actually DO it! Thank you! (y)(y)(y)
 

evranch

Active member
#7
Happy to help out. Programming is part of my business so I love the OpenTX radios despite some odd UI quirks. If anyone has any specific things they want to do with OpenTX, feel free to ask and I can try to guide you along the right path.

I plan on doing an Ardupilot UAV build thread too, once I get my new power package for my Maja and start rebuilding and re-tuning it. A couple people have expressed interest in how a mapping system is put together (i.e. repeatedly, with hot glue)