Vector somehow mixing flap and aileron signals?! - RC Groups
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Aug 23, 2014, 09:09 AM
Registered User

Vector somehow mixing flap and aileron signals?!

Hi folks. I've got a trad fixed wing with flaps. I'm using a Taranis RC Tx, EZUHF w/8ch. diversity Rx in SPPM mode. The flaps are on ch. 6, connected to an Rmilec PPM-PWM signal converter. Both the ailerons (on ch.2) & flaps are connected using Y-harnesses, with no 2nd servo mixes required.

The flaps respond normally to inputs on a 3-pos. switch. The ailerons, however, are acting as if they're mixed with the flap input on a 1 to 1 basis. With flaps up, they sit at full deflection as if for a roll to the left, and vice versa. They do respond to normal stick inputs, within the endpoints I have set.

I was sure at one point that I'd made a mistake in the wiring. One possibility seemed to be that one of the aileron servos had been switched with a flap servo and plugged into the y harness for the flaps, and vice versa, but I've re-checked all the connections and everything looks ok.

I tried plugging the aileron harness directly into the PWM outputs from both the Rx and the signal decoder. Either way eliminates the bad "mix", but of course leaves the ailerons unstabilized . If I completely disconnect the flap servos, however, the ailerons still show the improper response to the flap inputs, which suggests to me that the Vector is the source of the spurious signals.

At this point, I've run the Rx wizard repeatedly, to no avail. One question I have is, why is the flaps channel even included in the wizard for mapping purposes? It isn't involved in any of the mixing functions the Vector is supposed to handle, is it? Couldn't it be just be ignored for purposes of setting up the Vector, the same as (for example) the PTR servos?

What would happen if I repeated the wizard, leaving out the flap channel mapping? In effect, the Vector wouldn't even know there were flaps, so the "bad" mix would be certainly be eliminated, correct? Is there any intended functionality that would be adversely affected?

Without stabilization, my airframe requires a robust (42%) down flap-elevator mix, to keep it from pitching up when the flaps are in use. I've used a Guardian 2D-3D in it in the past, and I recall that this issue could be managed with stabilization alone, if the gain was set high enough. If I'm using the Vector with stabilization turned off or in 3D "Gyro" mode, however, and until I get the gains tuned, some elevator compensation will be required when the flaps are in use. So, even though the Vector manual says to set up the Tx with no mixes, I have left in a flap-ele mix, on a switch. Could this somehow be part of my problem? I've tried the ailerons with the switch for the mix in both on and off positions, which seems to make no difference either way. I'm running out of ideas, however, so I may try taking the elevator mix out altogether and see what that does.

I think that covers everything. Thanks in advance for any words of wisdom you can send my way!
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Aug 25, 2014, 08:45 AM
JohnET's Avatar

If you have dedicated flaps connected directly to your RX, select "None" on the flaps dropdown when in PPM/SBUS mode. If you are using traditional PWM mode, do not connect any of your flap channel wires to the Vector.

If you can't get it sorted, please open a support ticket and we will help you get it sorted.

Regards, John
Oct 02, 2014, 01:10 PM
Registered User

Belated thanks

John, your fix was right on. I just noticed that I never replied to let you know that I followed your instructions successfully and resolved the problem, so I just wanted to post a belated update and say thanks.

One other thing. Basically, it seems that if you tell Vector you're using flaps and set up a switch, Vector interprets this not a conventional setup for independent flaps, but as a flaperon mix setup, which it then takes over and performs. I'm a bit surprised that this issue hasn't come up more, because there's nothing in the manual or software that explains this. The instructions seem to say you should do the flap switch setup if you have actual flaps, while the opposite is true, and I didn't see any indication anywhere that Vector has the flaperon functionality. Am I missing something, or does the manual and software need some clarification on this?

Anyway, thanks again for the help!
Sep 12, 2016, 11:55 AM
Registered User
steve slade's Avatar

ppm flaps

Where do the flap servos plug into the vector when using PPM?
When maping the M5 or M6 outputs the dropdowns only give second ail, elev or rudder as options. How do I have one of these control the flaps?
Thank you
Sep 12, 2016, 12:14 PM
JohnET's Avatar

Dedicated flaps must connect directly to your receiver, not the Vector.

Regards, John
Sep 13, 2016, 03:13 AM
Registered User
steve slade's Avatar
I had to go to pwm and not ppm as there is only one receiver output with ppm.
Thank you for answering so quickly.
May 09, 2018, 01:26 PM
Registered User

Flap Problem in Sbus or CPPM

Wow! I've been fighting this problem for a couple of weeks. Finally looked at this forum and presto found the answer. Should have looked here two weeks ago!

Interesting that this problem has been around since 2014 with EagleTree not putting something in their documentation or including a note/fix in their PC software.... Shame on the engineers/programmers at EagleTree!

Lot of time wasted figuring this one out.
May 09, 2018, 01:49 PM
JohnET's Avatar
Sorry you have been struggling with this. We do cover this in the manual in section "3.5.7 Connecting Receiver and Servos/ESCs to the Vector " where it states;

If you have dedicated flaps, they do not connect to the Vector. Connect the flaps directly to your receiver channel that is controlled by the desired flap switch.

Or is there some other issue you are referring to?

Regards, John

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