Differential thrust on DX8e? HELP!

[Joe Carpino]

Does anyone out there know how to program differential thrust on a DX8e? I’ve tried several methods but I can’t get it to work and I’m getting really frustrated.

 

[chrisvdv]

This is for the FT Legacy.

 

[chrisvdv]

This is also a good reference to differential thrust setup. It is the same for the DX8e.
https://www.flitetest.com/articles/differencial-thrust-setup-on-a-spektrum-dx9

 

[Joe Carpino]

This is also a good reference to differential thrust setup. It is the same for the DX8e.
https://www.flitetest.com/articles/differencial-thrust-setup-on-a-spektrum-dx9

I tried using that tutorial but when I try to set the auxiliary for throttle the auxiliary channel gets removed from my mixing options

 

[chrisvdv]

As in the tutorial you have to assign the channels first before you do any mixing.

 

[chrisvdv]

Did you do the assigning in the "Channel Input Config" screen and not in "Rx Port Assignments" screen?

 

[Joe Carpino]

As in the tutorial you have to assign the channels first before you do any mixing.

As in the tutorial you have to assign the channels first before you do any mixing.

Yes, I did that but once I set the AUX1 channel assignment to throttle, AUX1 gets eliminated as an option in mixing

 

[Joe Carpino]

Did you do the assigning in the "Channel Input Config" screen and not in "Rx Port Assignments" screen?

Yes I assigned them in channel input config

 

[chrisvdv]

What Rx are you using? 4 or 6 channel?

 

[Joe Carpino]

6ch (batt/bind, throttle, aileron, elevator, rudder, gear, AUX1)

 

[chrisvdv]

Left motor ESC in RUDDER channel
Right motor ESC in AUX1 channel

 

[Joe Carpino]

So nothing in throttle? The mix does the throttle?

 

[chrisvdv]

Sorry, brain fade, should be Throttle.
Which model are we talking about?

 

[Joe Carpino]

I made my own 3D A-10 and I just want to mix in differential thrust but my DX8e won’t do it for some reason

 

[chrisvdv]

Send me a copy of the model configuration on your TX, and I will impot it on my TX and have a look at the file.
Page 27 of the manual tells you how to export a model file.

 

[Joe Carpino]

It wont let me attach the TX file

 

[Bricks]

i beleive you are going to have to do a mix throttle to rudder. Rudder as the master and throttle as the slave, as I have not done this before if you have the manual on page 31 and 32 it shows how to set up mixes, the manual is online.

https://www.spektrumrc.com/ProdInfo/Files/SPMR8100-Manual-EN.pdf

 

[Duck]

@chrisvdv I am also having issues here and I was looking at the shots above compared to the dx9 guide which I had been following. It looks like you have an extra "Mix 0" for Thr>Ax1. I tried adding that and it just made Aux1 stay at -100% when I adjusted throttle.

What I see on my DX8e is with the below mix I can raise my throttle to halfway and Aux1 mirrors it. Once I go full throttle, Aux1 stays at halfway. Because I am doing a bronco I am doing Vtail mixing using the built in mix but those don't appear to use Aux1 and instead mix REL and LEL.

My behavior

Throttle Stick -100% > Thr -100%, Aux1 -100% < Good
Throttle Stick 0% > Thr 0%, Aux1 0% < Good
Throttle Stick 100% > Thr 100%, Aux1 0% < Bad


My config that gives strange behavior (attached)

Channel Input Config
Aux1: Throttle

Mix 0
Rud>Ax1
Rate 100%, 0%
Offset 0%

Mix 1
Rud>Thr
Rate 0%,-100%
Offset 0%

 

[Duck]

The really weird thing, I also tried just using the "Channel Assign" setup as well just to verify the motors gave equal thrust. It gives the same behavior

I had thought I had it setup right for differential in Fall when I maidened my bronco but once I throttled up it pulled HARD right and resulted in a crash. That is why I was checking the mixes and noticed that above 50% throttle it just does the wrong thing. It is getting to flying season and I wanted to be ready to give it another shot once my field is no longer flooded.

 

[chrisvdv]

@Duck pm me the .spm file not as a .txt file so I can import it onto my transmitter. That way I will be able to go through the setup without guessing.