Differential thrust with throttle cut on the 2nd throttle channel

[xviper]

I'd like to put differential thrust on the following seaplane for better ground steering. I can do it in one of 2 ways ................... 1 way is to go into channel assign and tell AUX1 to be controlled by throttle OR 2, by doing a mix of Throttle>AUX1 (INH switch D). Doing the diff thrust with RUD mixes is easy. That part is easy. However, no matter which way I do it, I can't get Throttle Cut to work on AUX1 (2nd throttle channel), only on the main throttle. I've tried various mixes but the 2nd motor will not completely shut off with TC, only slows down. I would like TC to work on both motors. Anyone know of a solution?

Spektrum NX10, Lemon 8-ch. RX.

BTW, this is what I did with my old Flightline OV-10 motors, props, spinners and unused ESCs from my AL-37/PJ50.

[RRHandy]

I have come to the belief that you can't, I too have tried and no joy.

[Evan D]

Me three…

maybe with another radio (open source) but not with my DX-18.

[xviper]

I was afraid that would be the answer but was hoping someone found a "trick" that hadn't occurred to me. Still kicking around a couple of ideas. Thanks just the same.
Sometimes, if the wind is just right, I can give full rudder and blip the throttle to swing it around.

[kallend]

Can do it with my iX20, which has "multi engine" as an option under Aircraft Type. Set up a twin and you get an additional throttle channel (TH2) on which throttle cut works. Use receiver port assign to put it on whatever port you want. You can then mix rudder to THR and TH2 as needed for differential thrust, and throttle cut works on both. I use it on my Twin Otter floatplane.

Can also do it with an iX14. Not sure if the Gen 3 NX radios have it.

iX20 also has 3 engine and 4 engine options but I haven't used them/

[xviper]

Although very interesting and tempting, the IX14 will be something for down the road for me as I just got the NX10 a few months ago. The other option is to duplicate what's in my Beechcraft D18 which comes out of the box with diff. thrust. I think I'd need one of their dual smart ESCs and a smart RX to do it. Not inclined to spend another couple hundred just to get diff. thrust on this plane, let alone a thousand bucks for a new TX to do it.
This is my second Canadair CL-415. The first one was able to turn "OK" on the ground but it took some effort and space.

[kallend]

A quick Google search came up with several methods that apparently work on non-iX tranmitters. For example:

https://www.youtube.com/watch?v=ufDlCIrFNv8&ab_channel=PutzyTart

https://www.youtube.com/watch?v=xfsY9zAuhsg&ab_channel=RCplanesJohnReap

Disclaimer - I haven't tested these as I use the built-in method on my iX20 for my Lancaster and Twin Otter.

[xviper]

Will check those out.

[Evan D]

The first one looks plausible...

[xviper]

Using the TX monitor to observe what's going on ............................
The method from the video using the DX TXs and no sound ....................... I can't get it to work on my NX.
The method using the NX10 ................................ DOES work!
I will set up a couple of motors on the bench to test for real before applying it to my Canadair.

Like the fellow said ....................... It's "easy" when you think about it. The problem is that it never occurred to me to use a 3-position switch. I've typically thought of Throttle Cut on switch H, which is only 2-position.

Thanks to kallend for finding this. I was relying on videos I found by Google from years ago and none of those worked. I guess it just took some years (and new tech) for someone to tinker to come up with this. (Google has always been my friend. Just gotta do it more often to stay current.)

(Note: I see even RC Informer gave him props for this.)

[xviper]

Just confirmed on the bench the PutzyTart method and it works like a damn! He's says he's working on a slightly simpler way to do it over Xmas.

[kallend]

Just confirmed on the bench the PutzyTart method and it works like a damn! He's says he's working on a slightly simpler way to do it over Xmas.

[Ricky R]

Can do it with my iX20, which has "multi engine" as an option under Aircraft Type. Set up a twin and you get an additional throttle channel (TH2) on which throttle cut works. Use receiver port assign to put it on whatever port you want. You can then mix rudder to THR and TH2 as needed for differential thrust, and throttle cut works on both. I use it on my Twin Otter floatplane.

Can also do it with an iX14. Not sure if the Gen 3 NX radios have it.

iX20 also has 3 engine and 4 engine options but I haven't used them/

Are you sure about the IX 14? Because I have been struggling with this problem and when I read your post I grabbed my IX 14 but all I could find under "aircraft type" was wing and tail. Under the aircraft options I found throttle mode but all that offered was normal and reversed.
Am I not looking in the right place? Thanks.

[xviper]

The method using the NX10 ................................ DOES work!

I should report that since my last post on this, I have flown my Canadair water bomber several times and this method works like a damn. In fact, set at 50% it was way too much, so I've backed it down to 25%. Will see how this works next time I get to fly it. 50% was so severe that the whole plane would do pirouettes on the ground in one place if I was too heavy on the rudder.

[Ricky R]

OK so I checked a couple of other links on my search page, and found this on RCG"

" Spectrum iX12 differential throttle for twin

---

Differential Throttle, electric twin, for the iX12

1. You first set up a second throttle channel. Let's use AUX2. THRO will be the right motor, and AUX2 will be the left motor.

2. Go to Channel Assign and set the Input for Aux2 to INH. Port assignment for AUX2 will be AUX2.

3. Set up a Throttle Cut switch. Lets use switch H. Set the position to whatever you want. Most electrics will be -100% in the “cut” position.

4. Set up a mix, Normal, THR > AX2, rates 100% / 100%, 0 Offset, Trim enabled, Switch H. Highlight the boxes under the switch so that the AX2 throttle works when you are in the "run" position. When you flip to "cut" the THR channel will go to low throttle and AX2 will go to the center.

5. Make another mix, Normal, ON > AX2, with rates of -100% / -100%, 0 offset. Set the switch to H and make it active when you flip H to the "cut" position.

6. At this point you should see common action for both THR and AX2 for both positions of H. In one position they both operate, and in the other they both go to -100%.

7. Make another mix, Normal, RUD > THR, 0 offset, trim off, again using switch H so that the mix will be active in the "run" position. Adjust the Rates so that when you move the rudder stick to the right, THR goes toward low throttle. When you move to the left, nothing should happen on THR. (rate example 0% / 50%)

8. Make another mix, Normal, RUD > AX2, 0 offset, trim off, again using switch H so that the mix will be active in the "run" position. Adjust the Rates on this one so that when you push the rudder stick left, the AX2 channel goes toward low throttle.When you move the stick to the right, nothing should happen on AX2. (rate example -50% / 0%)

Done.

You only want the rudder to throttle down, never throttle up.
Both throttles should work together on the throttle stick, throttle cut should work on both throttles, rudder input should slow the motor on the side your rudder stick is moving."

This worked for me on my IX 14 with the exception in step 4, where my "AUX 2" (which I used gear channel 5 instead) the indicator went to the middle until I changed the rate to match the thr indicator. After that both channels worked together on the throttle stick and both went to zero throttle when I engaged the throttle cut. Then I made the mixes to the rudder and OH HAPPY DAY!!!

[kallend]

Are you sure about the IX 14? Because I have been struggling with this problem and when I read your post I grabbed my IX 14 but all I could find under "aircraft type" was wing and tail. Under the aircraft options I found throttle mode but all that offered was normal and reversed.
Am I not looking in the right place? Thanks.

You're right, I just checked and the option doesn't appear on the iX14.

It seems that it should be easy to implement, I wonder why it's not there.

[Ricky R]

You're right, I just checked and the option doesn't appear on the iX14.

It seems that it should be easy to implement, I wonder why it's not there.

Thanks for the reply. I'm very happy that I was able to do the job (which didn't seem like it should be a big deal!) using the instructions above. I never tried the 3 position switch solve because I don't want the throttle cut on a switch that does other things as well.

[xviper]

I never tried the 3 position switch solve because I don't want the throttle cut on a switch that does other things as well.

I can understand that completely. I'm a little concerned that mine is on a 3-pos switch but I've got voice alerts on each position so I remember what it does. I may give your method a try if the 3-pos switch gives me issues.

[Ricky R]

I can understand that completely. I'm a little concerned that mine is on a 3-pos switch but I've got voice alerts on each position so I remember what it does. I may give your method a try if the 3-pos switch gives me issues.

Make a "test airplane" and try the above method. The thing that did it for me was step 5, the ON mix. I had NO idea! But in step 6, my aux was still going to center when the TC was flipped, but I was able to adjust the rate to match the throttle.

[xviper]

Make a "test airplane" and try the above method. The thing that did it for me was step 5, the ON mix. I had NO idea! But in step 6, my aux was still going to center when the TC was flipped, but I was able to adjust the rate to match the throttle.

Just about to give it a try on a test model.