Unauthorised Mixing!

[Tosh McCaber]

Wee problem on one of my models.  Spektrum DX9 Tx.  Using six channels-

Right Aileron

Elevator

Rudder

Right Flap

Left Aileron

Left Flap

 

Ailerons only for turning- no mixing. 

 

Three position flaps (alone) for takeoff and landing, with compensating elevator mixing on the flaps, in the  "Flap System" window.  No other mixing.

 

All mixing inhibited on the "Mixing" window.

 

Unfortunately, for some reason  when the flaps are activated, it generates simultaneously a very small amount of right aileron.

 

Can't think why.  Hopefully some of you may be able to input some suggestions!

[Nigel R]

no throttle?

 

best guess is, the switch is assigned to the aileron channel

[John Lee]

First thing is to isolate where the problem lies.

 

Check the Tx output - turn the roller to the 'Monitor' screen, operate the flaps & see if one or both of the aileron channels move.

 

If they do than dive deeper into the TX or just set up again on a clean memory.

 

If they don't then the problem is in the Rx or model wiring.

 

[Tosh McCaber]

I am embarrassed!  Old age creeping in!  Should have included the throttle in position 1.  Should have read:

 

"Spektrum DX9 Tx.  Using SEVEN channels-

Throttle

Right Aileron

Elevator

Rudder

Right Flap

Left Aileron

Left Flap"

 

What I'm going to do is to set up a a new model on the tranny from scratch, with the same input controls that I have presently.

 

I'll post again afterwards.

 

Thanks for the replies!

 

 

 

[MattyB]

Not a  Spek expert, but do you have Flight modes set up? FMs have their own separate trim values, so if flaps are deployed via a change of flight mode, then that might explain the aileron offset that is being introduced. If FMs are being used, go and check the trims on aileron, and set them to the same values in all FMs.  

[Keith Billinge]

Tosh,

Can't you put either the ailerons or flaps on a Y lead and simplify the programming?

 

KB

[Nigel R]

DX9 offers dual aileron + dual flap as a wing type option, so this should be fairly straightforward.

 

Tosh, when you say 'a small amount of right aileron' do you mean both ailerons move, or just the right hand aileron?

[MattyB]

57 minutes ago, Keith Billinge said:

Tosh,

Can't you put either the ailerons or flaps on a Y lead and simplify the programming?

 

KB

 

Learning how to use the functionality of your TX is now a key part of the hobby, and dual aileron servos is pretty basic stuff, not to mention extremely useful - without it tuning differential on the fly or setting up flaperons is impossible to do. Yes, I know this doesn't remove the requirement for correct linkage geometry, but setting everything you need up mechanically off a y-lead is far less flexible, and often won't allow you to achieve your goals (e.g. flapperons, spoilerons, crow, quatro flap, snapflap etc.), especially when you come to models with 4-servo wings. 

 

The OP has a solidly capable TX in his hands, but if he never learns to use it's key functions, that is completely wasted. Spending some time now to troubleshoot the issue is well worth it, as that can be re-applied to more complex models in the future.

Edited September 11, 2023 by MattyB

[MattyB]

17 minutes ago, Nigel R said:

Tosh, when you say 'a small amount of right aileron' do you mean both ailerons move, or just the right hand aileron?

 

Very sensible question @Nigel R. An additional one from me...

 

@Tosh McCaber, when you say "...when the flaps are activated, it generates simultaneously a very small amount of right aileron", do you mean the flaps are on a switch and the ailerons move to their new position in one go then sit at a new datum until the flaps are retracted (indicative of a flight phase trim difference), essentially giving a small amount of right trim? Or does that aileron get driven right as flap is deployed, left as it is retracted (more indicative of a master/slave mix)?

[Tosh McCaber]

Thanks for your latest missives.  I'll start this with letting you all  know that I went back to square one.  I introduced the model again onto the DX9 as a new model.  I then input the exact control parameters as the previous (faulty) set-up, having noted every piece of data on the original-

Servo Set-up

D/R and Expo

Throttle Cut- (Safety Cut)

Mixing- (Flaps/ Compensating Elevator)

Flap System

Custom Voice Set-up

I then paired it back to the model (having taken the prop off, and checking that Throttle Cut was on!!)

Tried all the controls- everything identical to the previous set-up- except- no unwanted aileron mixing!  I'm glad to say!

I still don't see how that came about in the original set-up.  However, I'm deleting the original model from the tranny!

 

It's useful to do a full set up routine from time to time, to remind one how to do it - these trannies are so darn complicated!

 

In answer to your query Keith, I have the four wing servos in case I want to couple ailerons with flaps for roll, as a variation.  And -as the energy companies don't tell us- because I can!!

 

Nigel and Matty, previously, there was a very small right aileron on both ailerons as the flaps were being deployed.  I'm still blowed if I can see why this was happening on the original!?  Can't see any difference between old and new?

 

For everone's interest, I'm downloading a copy of the chart very kindly passed to me by Leccyflyer some time ago, which shows the list of (completely random) names associated with Custom Voice Set-up on the DX9 (and hopefully other trannies in the Spektrum range).  Before obtaining the list, it was a nightmare to go through each and every random name to find the one that I was looking for!)  Hope that you can read it!

 

Thanks for all your help!

 

 

 

Edited September 11, 2023 by Tosh McCaber