Differential in elevator set-up

Love the 9x? Use FRSky? Post your questions and answers here!
Post Reply
heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Differential in elevator set-up

Post by heliperry » Thu Feb 13, 2020 11:41 pm

Ok, I'm really struggling on how to program Differential in my X12S open tx. I've been trying to get my IMAC plane programming done and I'm frustrated. I've read a reread the user manual on the Horus X10/X10S that I bought being told this would help me in understanding open tx. Well I've programed it the way it said for a basic plane and it won't work! 😤 So I'm asking for some guidance on this or should I give up and send my 2years new tx back to have the tx put back to standard program. I've had this thing for two years and haven't trusted my program to fly my plane on yet. So this is the year to dive in.
Please help!😤
heliperry


pmullen503
Posts: 250
Joined: Sun May 06, 2012 8:37 pm
Country: -
Location: Fond du Lac, WI

Re: Differential in elevator set-up

Post by pmullen503 » Fri Feb 14, 2020 2:04 am

When you say "it won't work" what do you mean? Can you get your servos to move at all?

pmullen503
Posts: 250
Joined: Sun May 06, 2012 8:37 pm
Country: -
Location: Fond du Lac, WI

Re: Differential in elevator set-up

Post by pmullen503 » Fri Feb 14, 2020 2:04 am

When you say "it won't work" what do you mean? Can you get your servos to move at all?

heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Re: Differential in elevator set-up

Post by heliperry » Fri Feb 14, 2020 2:25 am

Yes they move but they move equal distance. I'm running two elevator servos one o channel 3 and one on channel 7 . I'm trying to get differential on low rates to high rates. I've used mixes with no progress. I'm just stumped! Hope this helps. If not contact me again.

User avatar
MikeB
9x Developer
Posts: 16741
Joined: Tue Dec 27, 2011 1:24 pm
Country: -
Location: Poole, Dorset, UK

Re: Differential in elevator set-up

Post by MikeB » Fri Feb 14, 2020 10:25 am

Differential is normally applied to ailerons so they move up more than down.
Are you actually trying to get high and low rates working on the elevators?

One way for this:
On each elevator channel put 2 mixes:
+100% Ele
R 70% Ele switch(SA^)
Note that the second mix has a "Multiplex" type of "Replace".
With the switch SA UP, you will just have 70% of full movement, with the switch in the middle or down, you will have 100% of movement.

Mike
erskyTx/er9x developer
The difficult we do immediately,
The impossible takes a little longer!


heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Re: Differential in elevator set-up

Post by heliperry » Fri Feb 14, 2020 10:55 am

Mike, the Aero works Extra 260 shows for throughs on low rates 12 degrees up and 16 degree down and high rates 18 degrees up and 24 degree down. This is why I'm trying to program Differential on the elevator. So to the answer to your question is yes I'm trying to get a high and low rate on the elevator. I will try your suggestion and see if it will work. Thank you I'll get back to you.
I do have a dumb question, on the enput page there is listed only for control's throttle, ail, ele, Rudd. Do you need to list all other channel enputs also for instance right ail, right elevator?

heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Re: Differential in elevator set-up

Post by heliperry » Fri Feb 14, 2020 11:23 am

Mike, after thinking more about your salutation it is more for programing high and low rates isn't it not programming differential?

User avatar
MikeB
9x Developer
Posts: 16741
Joined: Tue Dec 27, 2011 1:24 pm
Country: -
Location: Poole, Dorset, UK

Re: Differential in elevator set-up

Post by MikeB » Fri Feb 14, 2020 11:59 am

Yes, but you may also get differential throws in the mixes. In each mix, you may set the curve type to "diff", then adjust the value to get a reduced throw on one side, a positive value reduces throw on one side and a negative value reduces throw on the other.

Inputs are just that, the 4 sticks currently. You could set rates up there, but for now I suggest you just use mixes.

(I don't use openTx, I maintain and use erskyTx).

Mike
erskyTx/er9x developer
The difficult we do immediately,
The impossible takes a little longer!

heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Re: Differential in elevator set-up

Post by heliperry » Fri Feb 14, 2020 12:08 pm

Ok, right now I have my rates on the enput side. I will remove them on the enput side a try your suggestion. Thanks again Mike I will let you know how it goes 😊.

pmullen503
Posts: 250
Joined: Sun May 06, 2012 8:37 pm
Country: -
Location: Fond du Lac, WI

Re: Differential in elevator set-up

Post by pmullen503 » Fri Feb 14, 2020 1:02 pm

Couldn't you use a curve on the elevator channel? Or two curves for dual rate?

heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Re: Differential in elevator set-up

Post by heliperry » Fri Feb 14, 2020 1:16 pm

Are you saying on the enput page side or mix page?

User avatar
Kilrah
Posts: 10421
Joined: Sat Feb 18, 2012 6:56 pm
Country: Switzerland

Re: Differential in elevator set-up

Post by Kilrah » Fri Feb 14, 2020 3:22 pm

Rates need to be in Inputs, otherwise your trim will be affected when you change rates.
Differential however is best set in the mixes.

heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Re: Differential in elevator set-up

Post by heliperry » Fri Feb 14, 2020 5:47 pm

Ok, so if I put my rates in the input side for dual rates to get differential should I use differential % on the mix page? Another question. To get my elevator servos to track the same should I use a curve to get them to follow the stick movement the same. I put the rates on the mix page it kinda works but I'm not getting the same travel on my right servo as the left when I have it on high rates and elemenate the switch position.

pmullen503
Posts: 250
Joined: Sun May 06, 2012 8:37 pm
Country: -
Location: Fond du Lac, WI

Re: Differential in elevator set-up

Post by pmullen503 » Sat Feb 15, 2020 12:26 am

If the servos are getting the same input but your elevators aren't moving the same then there is a problem with the mechanical set up. Horns could be different heights or different distance from the hinge line. Do the servo arm positions match each other exactly throughout their travel? Sometimes a servo arms are off a notch or two and that will give different travels after you mechanically set the zero position.

Putting each servo on its own curve so the flight surfaces match is possible but should be a last resort. I had to do that once for flaps. The original builder had messed up the flap linkage and short of rebuilding the flaps there was no other way to fix it.

heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Re: Differential in elevator set-up

Post by heliperry » Sat Feb 15, 2020 1:17 am

Pmullen503
I have checked the machanical setup on the elevators and everything seems to be correct. I am going to check everything out again to double check things.

heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Re: Differential in elevator set-up

Post by heliperry » Sat Feb 15, 2020 4:15 pm

Pmullen503,
You were right about a machanical issue. I had on of my elevator control rods longer than the other. I fixed that issue.👍
Reset elevator servo's center's. Started over on my throes and was able to get on low rate on my left elevator +12 degrees and -16 degrees on down elevator with use of the differential -80% to get the -16 deg. Now for the right side elevator I program it the same way thinking I'd get the same results But I'm not able to for some reason. The differential % only works in one direction. So I can't move my down elevator to -16 degrees. Any thoughts on this and what I should do?
Still Struggling 😤

User avatar
MikeB
9x Developer
Posts: 16741
Joined: Tue Dec 27, 2011 1:24 pm
Country: -
Location: Poole, Dorset, UK

Re: Differential in elevator set-up

Post by MikeB » Sat Feb 15, 2020 5:10 pm

Differential reduces the movement on one side, which side is controlled by using either a +ve or a -ve value. First set the mix % to get the larger throw, then adjust the differential to get the lower throw.

Mike
erskyTx/er9x developer
The difficult we do immediately,
The impossible takes a little longer!

heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Re: Differential in elevator set-up

Post by heliperry » Sat Feb 15, 2020 6:28 pm

MikeB
I tried what you suggested and it worked on the right elevator that I wasn't able to get my Differential to work originally. But It wouldn't work on the left side so I left it the way it was.

heliperry
Posts: 34
Joined: Sun Jan 27, 2019 2:01 am
Country: -

Re: Differential in elevator set-up

Post by heliperry » Sat Feb 15, 2020 9:12 pm

Mike,
I redid what you suggested and figured it out. I have it working the way I think it should. Everything tracks together also. I have my final rates also. Know I just need to work on my ailerons and rudder next.🤗
I'm sure I'll have more questions.
Thanks again. Heliperry


Post Reply

Return to “The FRSKY Forum”