Delta mixing on DX7 & DX6i

[Jonathan Lewzey]

I've recently finished an alula EVO and have set it up on spektrum 2.4ghz with a AR6100 receiver. I have both the DX6i and DX7 transmitters, but while both have delta (tailless) mixes, I cannot achieve the required control throws for this model. The alula requires lots of aileron and very little elevator, but both transmitters ATVs are specific to the channel, programmed, not the mixed surface. Is there any way i can make the ailerons move more than the elevators using either of these transmitters? Can it be done mechanically? I can't see how spektrum haven't seen these issues on not one, but two of their transmitters!

[Frank Skilbeck]

I had the same problem with my Wildthing, I changed it over to 2.4 on my Dx6i and it basically halves the available aileron or elevator throw, so it's gone back to 35 MHz and my Cockpit Sx with proper mixing. I know the Futaba 6 channel sets basically have the same limitation but I'm surprised the Dx7 does.

 

I think the mixing on the JR 35 mhz 9 channel sets is fine, so maybe the 2.4 DSX9 will be good too.

[Andy Harris]

I'm in the final stages of a Googlie build and came across similar issues.

 

In you case you can do one of three things.

 

 a) drop the delta mix and mix to two spare channels, then  mix the ailerons and elevators to these channels.

 

 b) with delta apply rates and expo to the elevator mix.

 

 c) with delta mix the elevator back to the elevators and ailerons.

 

 d) [I know I said three] There is a setting for delta differential

 

The Googlie is a sort of small two motor Zagi.

I mixed throttle to flap at 100%, the second motor is on flap.  Mixed rudder to throttle at 40%, Mixed rudder to flap 40% in the opposite direction.

Selected Delta and set the sensitivity of the elevators using rates.

 

Regards

 

 

Andy

[Tim Mackey]

Strange.... I use a DX7 for my WT and can get far more throw on both elevator and ailerons than recommended...certainly enough to flick her into a spin if I pull too much el.

Same scenario with wifeys WT ...on her DX6i

[Jonathan Lewzey]

I did have a similar problem with my funjet when chanigng over from my FF9 to DX6i too, but solved it in the end as the difference in aileron and elevator movement is minimal. The alula needs loads of aileron, but is really uncomfortable with lots of elevator, so its not a question of not getting enough throw (the DX7 does up to 150%).

 

I will try the methods you suggest, andy, but it may have to be converted to 35 mhz if i cannot find a solution.

[Jonathan Lewzey]

Does anyone konw how to turn off (or change) the noise the DX7 makes when you press a button? it is really annoying

[Tim Mackey]

I forget now how I did mine ( it was 3 years ago )

It may be via the secret hidden service menu, The usual disclaimers apply, but if you want to know how to get into this menu...here you go.

 

DX7 SERVICE MENU

 

Ensure the Aileron D/R switch is in the UP position.
Press and hold the DOWN and SELECT buttons and turn on radio.

 

 Now you're in the setup menu.

Scroll up/down until you get to the screen that says [Model Reset]
Press the Adjust Decrease button (r/h side of LCD)
Flip the Aileron D/R switch down
Press the Adjust Increase button
Flip the Aileron D/R switch up
Press the Adjust Decrease button

Keep alternating this Aileron D/RATE up/down and Adjust Increase/Decrease sequence (about 5 cycles)

The radio will 'beep' and the LCD will go dark. This is the LCD test.

Scroll Up/Down (left side of LCD screen) through the Service Menu (at your own risk)

 

To end…scroll to “accept changes type screen”

Edited By Timbo - Moderator on 20/10/2009 12:25:22

[Jonathan Lewzey]

cheers, timbo, i'll give that a go later . I was programming in model names yesterday and it literally gave me a headache!

[flytilbroke]

Using my Dx7 I required something similar for my Northstar, I had on 35Mhz used flaps / aileron mix. On the dx7 I had to do something similar as neither Delta or elevons could get me what I needed which was to get elevator mix to act on the wing control too, giving full up down control wing and tail on the stick.

 

Does not help the button pushing, lets you know it can be done.

[Peewhit]

Jonathan.

There is a very simple solution with the DX7 which is very easy to miss as it is only mentioned as a note on the wing type -  page 40 of the manual.

With delta wing type active, servo adjust alters the throws of the individual servos and does not distinguish between aileron and elevator.

Separate throws for aileron and elevator can be set using the dual rate function.

To reduce the elevator throws go into the dual rate function and dial down the %age factor for elevator.

For my Wild Thing I did this with the dual rate switch in both positions and set the same %age. This then renders the dual rate switch inactive, just in case you accidentally knock it.

[Jonathan Lewzey]

cheers peewhit, i'll try that, sounds just what i'm looking for.

[Tim Mackey]

Incidentally, due to a stupid ( IMO ) quirk of the software systems in the DX7 and DX6i being different, you cannot simply swop from one Tx to the other on a delta mixed model.

I wanted to do just that, but after rebinding the model from my DX7 to my wifes DX6i, I discovered that the servos needed to be swopped over between aileron and elevator ports!

I discussed the issue with HH, and they confirmed this is the way it is !  Crazy .

[Jonathan Lewzey]

Got it to work. Dual rates is the trick with this although I had to use 150% on the individual throws aswell. Re-test flight soon (I'm expecting great things)

 

Here's a picture of my alula. Like my paint scheme?

 

[flytilbroke]

A real beut' of a camoflage  Nicely done

[Peewhit]

Glad the dual rates sorted it out for you and love that paint scheme!