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Spektrum DX9 Crow Programming Query

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Pete C14/11/2019 22:20:32
14 forum posts

I recently purchased a DX9 transmitter and I am currently trying to set up a 4 servo wing glider.

I have managed to get crow working mostly by trial and error (the manual is completely useless).

To activate crow my preference is for the throttle/spoiler stick to be in the 'down' position for normal, and for the crow function to be progressively applied as the stick is moved upwards. Currently it is working opposite to this.

Does anyone know how I can reverse the function of the spoiler stick to achieve my requirement? Everything I have tried so far has failed.

I am aware of the different preferences that people have regarding the direction of this functionality but my preference, and the one I am familiar with, is the one described above.



Edited By Pete C on 14/11/2019 22:28:09

Shaun Walsh14/11/2019 23:13:45
318 forum posts
49 photos

Can you not just reverse the throttle function in the settings?

Steve Houghton 115/11/2019 09:08:55
1911 forum posts
128 photos

Does the Spektrum not have the throttle stick up in the CROW off position as the default? Don't forget to add some elevator compensation, probably a tiny bit of down will do it.

Pete C15/11/2019 10:08:52
14 forum posts

Thanks for the responses:

Shaun, unfortunately this facility is not showing as available. I think it must be disabled when you select the 4 servo wing type.

Steve, yes, I think this is the problem. I just wondered whether anyone had managed to find a way of reversing this function.

Steve J15/11/2019 10:18:53
1906 forum posts
54 photos

How are you programming the crows? You should be in the Camber System.

John Lee15/11/2019 10:32:04
743 forum posts
72 photos

Pete, I responded to your Private Message earlier this week & offered to send you my set-up for the Heron. It is still showing as 'unread'. If you look in your inbox (top of page next to 'settings' ) you should find my Message. John

Edited By John Lee on 15/11/2019 10:32:35

Pete C15/11/2019 12:42:32
14 forum posts

Steve, yes, I have set up the crow function via the Camber System page.

Pete C15/11/2019 12:46:24
14 forum posts

John, thanks for the message. I have now sent an e-mail to you.


Pete C17/11/2019 18:07:41
14 forum posts

For the benefit of anyone trying to get their crow to function from the THR stick with the crow being deployed as the stick moves from 'down' to 'up', I confirm that it is achievable.

Camber System screen.

Input: THR (throttle stick)

Offset: negative value

Typically POSITIVE values in the UP column.

Typically NEGATIVE values in the DOWN column.

It will be a case of trial and error so put in some values and move the stick to see what happens. When you get the desired directions for control surface deflection you can then work on the values to get the amount of movement required.

Have fun


Peter Jenkins17/11/2019 23:35:13
1595 forum posts
264 photos

Pete C, I'm a little surprised that you want to set your crow braking the opposite way round from both full size gliding practice and throttle direction for model aircraft. I see that you have now achieved it but why have it the wrong way round?

Frank Skilbeck18/11/2019 08:07:15
4726 forum posts
101 photos

He's not the only one, I have a friend who prefers the same, says it makes using the rudder in normal flight easier and stops inadvertently deploying the brakes, I often fly his models so I have to remember this........

One thing to watch, and I'm not sure it applies to the DX9, is that if you radio has aileron differential suppression as the ailerons are raised is that you reverse the stick operation not the butterfly operation.

Pete C18/11/2019 13:15:25
14 forum posts

I thought this might happen!

Peter, I do not consider there to be a right or wrong way round when it comes to operating crow/spoilers, just personal preference. Thinking back to when I first built a model glider with front hinged 'barn door' type spoilers (about 40 years ago) it seemed logical to me to operate them with the stick moving upwards. This was generally in common with most of my then club members some of whom are very well known names in the model flying fraternity.

I do not recall at that time, there being any consideration given to relating the stick movement to full size practice. It was just the norm with the people I flew with regularly.

In common with Frank's friend, I have become very used to the rudder function being from the down stick position.

Please note that I have not referred to where on the transmitter the throttle/spoiler stick might be. Some people fly with different stick modes and again I do not believe there to be a right or wrong mode just personal preference or maybe first flights were done using that particular mode.

Additionally, just to spoil your day, I also use the same stick orientation for throttle control and spoilerons!

Frank: I am not familiar with 'aileron differential suppression' and do not understand your description.


Edited By Pete C on 18/11/2019 13:18:22

Steve Houghton 118/11/2019 15:30:10
1911 forum posts
128 photos

All of my pure gliders use the throttle stick to operate crow from top (crow off) to bottom (crow on), except for my electric motor Heron which I decided to operate both the throttle and crow braking from the throttle stick. So with the stick in the lower position I flick a switch one way and I'm on throttle on, crow off. Flick the switch the other way and I have throttle off, crow on. It works for me and I don't seem to get confused with the opposite motion for crow. I don't like operating throttle from a switch only either.

Peter Jenkins18/11/2019 16:04:32
1595 forum posts
264 photos

As you say Pete C, it's what works for you. I was curious as to the reason for operating in that way.

Steve H - well, that would probably confuse me but, then again, I only fly power.

Talking full size, I think that pre WW2 some European countries had their throttle working in the sense of throttle forward = idle and throttle aft = full power. Post WW2 everyone reverted to throttle forward = full power as it was too dangerous to have 2 systems in use. But, that's full size and we can do what we want.

Pete C18/11/2019 16:35:16
14 forum posts

Steve H - Its a Heron that I am currently setting up. It is my intention also to use the throttle stick in dual function in the same manner that you describe.

If you have by any chance used a Spektrum TX to set up the switch function I would be interested to know how you went about setting it up.

I have used this functionality before when I was competing in electric height limited competitions but I was then using a JR TX. I remember that it took quite a bit of trial and error to get this initially set up but it worked great. After the motor run a flick of the switch meant that you were ready to deploy spoilers for the landing. Having remembered to first move the stick back to Down.

I also would not consider using throttle via a switch.

Frank Skilbeck18/11/2019 17:04:31
4726 forum posts
101 photos
Posted by Pete C on 18/11/2019 13:15:25:

Frank: I am not familiar with 'aileron differential suppression' and do not understand your description.

Edited By Pete C on 18/11/2019 13:18:22

If you have aileron differential dialed in so say the up going aileron travels twice as far as the down going aileron, when you raise both ailerons you may then get reduced roll control. If you have differential suppression as you apply crow/butterfly then the aileron differential is reduced so the down going aileron moves more, result better roll control when crow/butterfly is applied.

Pete C18/11/2019 17:09:07
14 forum posts

Frank: Thanks very much for that I will check it out.

John Lee18/11/2019 17:17:00
743 forum posts
72 photos

Pete, that's exactly what is achieved in the program I sent you, with a slight variance. On Switch 'B' in one position you have throttle on, crow off, in the other crow on, throttle off. The slight variance is that in the middle portion both throttle & crow are off so that you can move the throttle stick where you want, either for comfort in general flying &/or so that you can move the stick to your preferred position before engaging crow or throttle.

It's done by:

System Setup>Rx Port Assignments Select 7 AUX2,:Motor, then next Page assign 7:Thr. Your ESC is plugged into that channel (7) & the Throttle stick operates it.

You then need to over-ride the throttle stick when you operate crow so the motor does not run. This is done by using Throttle Cut.

So to walk you through:

System Setup> F-Mode Setup select the Switch you want to use (I use B) & enable 2 or 3 flight modes. In Spektrum each Flight Mode is effectively a separate model memory and you can set up how you like in each.

Function List> Throttle Cut. Set Position -130% Set Switch: Flight Mode and in the boxes below toggle on or off so that it is active (filled in) at whichever position you want to use crow. Throttle will only work on the motor in the positions where the box is 'hollow', in the other positions the Throttle cut will over-ride.

Then Function List>Camber System set the flap movement to 0% in the Flight Modes where you don't want crow to operate.

Hope that helps

Frank Skilbeck18/11/2019 17:19:11
4726 forum posts
101 photos
Posted by Pete C on 18/11/2019 17:09:07:

Frank: Thanks very much for that I will check it out.

Worth checking, on my friends model we did it by adjusting the spoiler input in the aileron and flap mixers and ended up with differential suppressed in normal flight and full differential when the stick was moved up, made for an interesting flight. Landed, "reversed" the stick direction and adjusted the mixers and all was good.

I'm not familiar with the Dx9 glider programming but on my MPX sets you need to tell the radio which way you are using the stick, on others I've seen the ability to set aileron differential at each end of the stick movement.

Pete C18/11/2019 21:49:32
14 forum posts

John - I have created an additional TX model memory using the file you kindly sent.

I now have three different versions for the Heron that I am working with. As this is a new TX I am keen to get familiar with its functionality so that I can apply that knowledge to the set up of of my other current models as I move them over to the DX9, and also a few still in the pipeline.

To that end, the detailed information you have sent to me today is invaluable. Thanks very much.

I am currently playing with a set up that has Cruise, Thermal, and Speed as three modes on switch 'B' with the crow braking available whilst in the Cruise mode, and then using the two position switch 'A' to toggle between crow and throttle on the throttle stick.

I am very appreciative of the help and advice that you and other forum members have offered to me, it is a great facility both informative and friendly.

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