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Crashes Using Trainer Function on DX18 Radio

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Old 06-19-2019, 12:52 PM
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on_your_six
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Default Crashes Using Trainer Function on DX18 Radio

OK... so now we have lost four inexpensive foam planes trying to use the wireless trainer mode in the DX18 2nd gen. The only thing that I would consider unusual is setting the trainer switch to the gear switch ("A") instead of the push button switch ("I"/bind). We check everything out on the ground and it seems to be working fine. Double check even. We have also range checked Buddy boxing. We are buddy boxing a 6month old DX9. The DX18 was sent in for service a couple of months ago because it was not turning on sometimes.

So the instructor takes off and gets to level flight and flips the "A" switch. The student gets control and looses control rather quickly. The second you touch the stick on the instructor radio, it says instructor has control and plane proceeds to fly straight into the ground without any flight control movement(A switch remains in student mode). We have changed radio, ESC, motor. Everything that we can think of. We have used "Pilot Link Master", and "Programmable Master" modes. User Manual is worthless explaining these functions.

We are running out of cheap foam test planes. We sure don't want to put any money into the air with this bug going on. So what are we doing wrong?????
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Old 06-20-2019, 07:27 AM
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Once you move the sticks on the instructor radio, the instructor is flying it, not the student. It remains in instructor flying it. You have to cycle the A switch off, then on, to give control back to the student.

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Old 06-20-2019, 08:54 AM
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Both radios loose control. Plane takes a hard nose over 90 degrees straight down.

Not my first radio, I have been buddy boxing for years. Don't just assume that I don't know what I am doing. I think that there is a bug in your code.
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Old 06-20-2019, 09:08 AM
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Have you put an experienced pilot on the student side just to make sure what you're doing over there is right?

On your ground checks, is the student radio moving everything exactly as it should? Not the usual wiggle the sticks and see things wiggle, but make sure they wiggle the right way?

Where are you standing relative to one another, and relative to the plane?

How you configure trainer in both radios depends on a) how you have both radios programmed, and b) whether you're using wired or wireless mode. Please export the appropriate models from each radio and post them here so I can see what you have configured. Otherwise we'll be asking and answering configuration questions for the next few days.

Overwhelm me with information about the complete configurations and it might be enough!

Andy
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Old 06-20-2019, 09:09 AM
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Just so it's clear, only the instructor radio is talking to the airplane. It takes the information from the student radio and uses that to generate the RF.

The student radio talks to a standard remote receiver embedded in the instructor radio.

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Old 06-23-2019, 04:04 PM
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OK, today I was again with my student. Here are the unchanged settings from the last crash. The Blue Student is from a DX9 radio the Blue Cub Instr is from a DX18 radio.

Tell me what is wrong with my setup.
Attached Files
File Type: spm
012~10 New Blue Student.SPM (19.0 KB, 3 views)
File Type: spm
027~27 Blue Cub Instr.SPM (19.5 KB, 4 views)
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Old 06-23-2019, 04:40 PM
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Since you are using the Wireless Programmable Master, both transmitters must have the same programming.

You ALMOST have that.

The aileron channel in the Instructor radio is reversed, but not in the Student radio. This tells me you never either bound the student radio to the aircraft to verify correct operation, nor followed my item above "On your ground checks, is the student radio moving everything exactly as it should? Not the usual wiggle the sticks and see things wiggle, but make sure they wiggle the right way?"

On the instructor radio, you also have defined Mix 1 (RUD > AIL). While this probably isn't important, it IS a difference.

The easy way to get the programming right is to do all the programming in the Instructor radio, fly it, trim it, etc. Then export that to a file and import the file into the student radio.

My guess is that the student is losing control because the ailerons are backwards. The trainer is configured right now for the pushbutton, so you have to hold it down as long as you want the student in control. When you release it, you regain control. Master Override doesn't make sense in this situation - it's only for toggle switches.

Hope that helps. Thanks for providing the two files. It only took a couple minutes to glean all this.

Andy
BTW, the timers are configured differently as well. I recommend using Throttle Out as your timer start. It usually gives a more accurate value of flight time remaining.
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Old 06-24-2019, 06:38 AM
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Part of my problem is that I let the student do the programming with me checking over their shoulder. I will have to take over that total responsibility.

I find that interesting. We do a ground check. And not just a wiggle wiggle. I NEVER do a wiggle wiggle, always a slow deliberate check. I am not sure what he did. You are right about the rudder to aileron. I am a heli pilot so I USE RUDDER and a three channel plane with the rudder surface on the aileron channel drives me nuts. I thought that the instructor radio was setup for switch A the gear switch. The plane is gone so we will never know for sure.

WE LOST ANOTHER PLANE YESTERDAY
Bob Sparks of DCRC talked me into using pilot link master on the Apprentice with the safe system. Plane took off and flew away. Not happy about this situation at all. 5 crashes this year using wireless buddy box. Bob's main solution is to throw the safe system away and put a yellow receiver in the plane. Then he used Pilot Link Master. He says that is the only way he can get the wireless system to work.

I think that there is a lot to be done documenting wireless trainer functions and the User Manuals are too brief.

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Old 06-24-2019, 06:57 AM
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I did not think it was possible to exchange SPM files between radios. What radios will exchange files? I have DX8 (Original), DX9(new), DX18 2nd Gen

Do you have a utility that compares the SPM files? Is that available? I really don't want to write my own and the SPM file is not well deliminated. It would be really nice to use a laptop to compare the files after programming and before flying a new model.

What Wireless Mode do you recommend? I have always used programmable link master.

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Old 06-24-2019, 07:26 AM
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Your model has switch A configured onto the GEAR channel, which is typically used as the panic button (SAFE mode is on switch D). If you were flipping switch A instead of the push button, you weren't giving control to the student, but you were limiting the control authority of the instructor transmitter. Likewise, the student radio had the same setup, so it would be changing the panic mode based on the A switch if it were flipped in the wrong direction. Somebody didn't follow the manual for assigning the channels for the transmitter, or they changed from what the manual wanted. I figured you guys changed the configuration to conform to a club configuration standard, ignoring the manual settings intentionally. Was that not the case? Why didn't your ground check find these things?

The mix would not be an issue, I just wanted to highlight it as a difference between the two configurations. I have the same mix on my deBolt Champ 3-channel because my thumbs use both aileron and rudder automatically.

Nobody is going to disagree about the manuals being too small. We have over 60K posts in ONE THREAD over in RCG, much of which could (should) be in our printed documentation. That's not 60K new things - there's lots of re-asking and explanation and some trolls - but it's sizeable and a good variety of topics, including several discussions about WLT and training in general.

I've been doing WLT training for years, including during the development of it, and have exactly 1 crash which was my fault because the student was ready to solo and I was distracted and not paying close attention to him. My most recent student was my daughter this past winter. She was also trained using the SAFE mode, using an E-flite Mini Apprentice. After a dozen flights on very windy days she was flying solo. It took me some learning because of how SAFE is different for training.

As for SAFE, yes, that is a very different way to train pilots. My daughter is the only one I've used it with, and it definitely requires the instructor to relearn instructing. I wouldn't recommend an old instructor use it without learning how to fly in the SAFE mode himself. It's much better for self-instruction than formal training, imho. In that regard I'd probably do somewhat like Bob and simply change the switch so instead of being in the safest of SAFE modes to being in the least (which is only AS3X stabilization), though now that I've learned how to instruct a pilot in SAFE it wouldn't be necessary for me any more. Bob can save a couple bucks simply by changing the position of the SAFE mode switch.

A plane taking off and flying away is not a WLT fault. There's got to be more to it. The instructor was in control of the plane (or at least his radio was) - so why did he not control it? Did he have it on a switch and disable Master Override? That's not wise, but could be useful for an instructor who hasn't learned to keep his hands off the sticks while training. That's part of why I asked about having a qualified pilot acting as student, to make sure everything was right before handing it off to a newb.

So I do have one question for you. In the SPM files you sent, you made it so that the student radio has both SAFE and PANIC functions available to him. Why is that? Shouldn't you be keeping control of those on the instructor radio? That's what I'd recommend, since you don't want the student to accidentally change the stabilization mode. Also, in your configuration, since you have the panic function on a toggle switch instead of a momentary (first paragraph), that is going to change what you need to do in a panic situation. Not following the manual is OK, so long as you know and understand the changes you are making.

The wireless system works great in both Programmable Master and Pilot Link modes. How you configure the student radio is different, but for a simple 3-4 channel plane (with 2 channels for SAFE/Panic functions) it's not hard. Just different.

What I really need from you is an understanding of what exact difficulty you are having. Can you ask me questions about things you don't understand? Or maybe things you think you understand but aren't easily demonstrable? I can from the SPM files see that you ARE doing some things right, but obviously having a channel reversed in one radio isn't one of them, so there might be an understanding error, or a process error - both of which are easily correctable.

Andy
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Old 06-24-2019, 07:37 AM
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Originally Posted by on_your_six View Post
I did not think it was possible to exchange SPM files between radios. What radios will exchange files? I have DX8 (Original), DX9(new), DX18 2nd Gen

Do you have a utility that compares the SPM files? Is that available? I really don't want to write my own and the SPM file is not well deliminated. It would be really nice to use a laptop to compare the files after programming and before flying a new model.

What Wireless Mode do you recommend? I have always used programmable link master.
The DX8G1 needs a translation program to be able to share with the other radios (free software, a link is in RCG's Radios forum), but a DX9 and DX18 will share no problem. In fact, any of the newer radios (anything except DX7s/DX8 and older) from DX6e to DX20 will share files just by popping the SD card from one to the other.

The tool I used to compare the files is a standard programmer compare tool. There are lots of them available. The one I use is Wdiff version 1.49 from C.Sitte Softwaretechnik. For details about assigned functions I use PFE (Programmers File Editor) or gedit to view the text, or I load the file into my transmitter and look at it. The SPM file looks like software source code or INI configuration files. Unless you're a computer geek, you don't want to look at it that way. Use your radio(s) side-by-side.

I recommend Pilot Link for training, or Programmable Master for complex planes. With Pilot Link, you put a default model into the student radio. Just go to the Model Reset function. In the Instructor Radio, you program the panic and SAFE mode functions per the manual as normal, reversing, etc. To set up the trainer mode, you use the default Pilot Link settings, which make only the first 4 channels as coming from the student. I like to change the Switch from I to A, and have Master Override enabled. (You need to do this if you followed the manuals for the SAFE settings, as one of them is to put the pushbutton (I) onto channel 5). Then you select the BIND option on the Trainer screen, then bind the student radio to it.

Do a ground check to verify that everything moves exactly as it should. The student will have access only to roll, pitch, yaw, and throttle, and they will behave exactly as if you make the same movements on the instructor radio. In fact, I recommend you do that - hold full left on both radios, and toggle switch A (trainer) on and off to make sure they don't move. Do that for all controls.

The instructor will retain control of SAFE mode and Panic because they are on channels 5 & 6, which you didn't touch on the Trainer setup screen.

Andy
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Old 06-24-2019, 07:51 AM
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I do have a simple question that Bob brought up. He says having Expo on both the Instructor radio and the Student radio results in the expo being doubled. 20% + 20% = 40% expo to the plane. I say absolutely no way. Expos are not additive. What say you Judge Andy.

I was flying the plane yesterday as the instructor. Ground check immediately prior to flying passed. Took off and no control. Using Pilot Link master.

I am a software engineer.
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Old 06-24-2019, 07:57 AM
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It depends on which way the transmitters are configured, and how they are attached.

In Pilot Link mode, the instructor radio applies its expo value to the incoming signal. If the incoming signal is from a wired student that is configured for Normal training (Programmable Master mode), then the signal will include the expo/rates from the student, resulting in both being applied. If the incoming signal is a from a wired student that is configured for P-Link Slave, then the signal will be only the displacement of the sticks, and only the rates/expo in the instructor radio will be used. If the signal is coming from a wireless connection, then the rates/expo of both will again be used. That's why in the prior post I said to use a student radio in the default configuration. That will have NO expo/rates in either wired or wireless mode.

In Programmable Master mode, the instructor radio is a pure pass-through. Whatever the settings are for a channel in the student radio, they will be applied only by the student radio and then go directly through the master to the aircraft.

Andy
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Old 06-24-2019, 07:59 AM
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Originally Posted by on_your_six View Post
I was flying the plane yesterday as the instructor. Ground check immediately prior to flying passed. Took off and no control. Using Pilot Link master.

I am a software engineer.
Ah, good, then I can talk technical without a problem.

That would not be an issue with the trainer link at all. It would be an issue with the RF system of the master. Can you do the full-power range test as described in the "* Important Bulletin" found on the DX18 web page?

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Old 06-24-2019, 08:00 AM
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Oh, yes, the rates are not additive in a purely mathematical sense as expo is a nonlinear function, but they would both be applied to the result. It would be more logarithmic than additive, I think.

Andy
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Old 06-24-2019, 02:18 PM
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So if I understand what you are saying, a dual rate and the expo percentage would be applied twice to the resultant signal. Is that the case? If so, then do not use any dual rates on the student box? Then the boxes programming would be different. That does not make sense to me.

Thanks for any clarity. If this topic has such a long stream of issues, there should be a link to RCGroups and RCUnivere threads on the Spektrum website.

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Old 06-24-2019, 02:36 PM
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You missed the IFs.

IF the instructor transmitter is in Pilot Link mode, THEN do not use rates/expo in the student. ENDIF

IF the instructor transmitter is in Programmable Master mode (the file you gave me was Programmable Master mode), THEN you need to use identical programming in both radios. ENDIF

This is the only RCU thread I know of regarding this question. RCU is dead as far as radio support is concerned. When people contact support, there are a few folks there who know how to direct traffic to RCG to get the answers and/or interact with me. There shouldn't need to be links to anything other than Spektrum manual pages. Fortunately one of the guys on RCG is working on a general-purpose manual along the lines of what Sherman Knight has done for sailplanes. He's at 80+ pages already, and if I understood him correctly today, that's just the Mixing functions. I've written an Encyclopedia Britanica on the radios. It's a mildly sore subject for me, so let's move on.

Very simply:

Programmable Master requires both radios to be configured identically (with the obvious exception of trainer settings). The instructor radio simply passes the student signals through unchanged for all channels that are marked as pass-thru, and the other channels are sent based on the instructor's radio.

Pilot Link requires that the Instructor radio have all programming, and the Student have none. The Instructor takes the signals from the student radio, uses them in place of its own AERT sticks for doing the math, and then sends them out to the aircraft. Use the default trainer channel routing unless you really understand all that is happening.

In both modes the Instructor radio is the only one talking to the aircraft.

Andy
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Old 06-26-2019, 06:04 AM
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In the loss of the Apprentice with Safe receiver on this last Sunday. I flew the aircraft fine. I then selected the Pilot Link wireless selection. We set up a blank model in the student radio and bound it to the instructor radio. A differnt Model memory (in student radio) had been bound to this instructor model memory as programmable master.

Plane flew fine without wireless selected. When bound to student and then ground checked for controls everything was fine on both radios. Took off and it just flew straight away never to be seen again.
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Old 06-26-2019, 07:01 AM
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If you were flipping switch A to give the student control, the plane was in Beginner Mode and flying straight and level. Any inputs you made would have been greatly reduced. You would have needed to flip switch A to the other position to regain normal control. This is because switch A was set up as the flight mode control, and the pushbutton was the trainer control.

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Old 06-26-2019, 02:59 PM
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Sorry Andy, I thought that too. I had zero control, absolutely zero. I flipped both the A switch and the flight mode switch without any result.

Horizon repair guys want me to send in both radios.
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Old 06-27-2019, 06:37 AM
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I concur.

Andy
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Old 06-27-2019, 06:38 AM
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Wouldn't be a bad idea to include the receiver, too.
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Old 06-27-2019, 03:47 PM
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duh... it is in the plane that flew away.
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Old 06-27-2019, 03:57 PM
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Sorry, I didn't realize you didn't chase it down. We chase down "fly-aways." I've only ever lost one RC plane - a UMX in a 200 acre corn field at dusk, heading downwind (too strong a wind to return with no power) and one FF plane - a 13" span Baby BiWinger again at dusk as it headed into thousands of acres of woods.

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Old 06-28-2019, 01:57 PM
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Sorry, wrong thread
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