Trutrak/Mic Key problem

That is not satisfactory!

Bill,

that sounds not good at all! I am not going to fly with an AP that I know, is not working properly! Flying out to the factory is not an option for me (from Belgium). The problem needs to be cured before I build on anyway! After all the effort I put in, adapting the controls, installing brackets, wiring, installing the servo's, cutting my panel, testing, etc., there is just no way back! Trutrak will have to make this work!

This problem so far has cost me over $ 600,- in shipping cost, coax connectors, wire, import duties and VAT, (on the return parcels, because the Belgian Customs charge it anyway, even with the paperwork saying it is a free repair). So far I have paid all these costs, without arguing with Trutrak about it, because I was under the impression, from Lucas, that Trutrak were also doing their best and were going to cure this problem pretty pronto.

Yesterday Lucas asked me at what frequencies the problem occurred. I haven't heard from him since my answer yesterday. I will give him some more time before I start calling.

Thanks for sharing, maybe....., maybe... your problem will get solved when they find the cure for my problem, who knows.

Please monitor this thread.

Kind regards, Tonny

Pilottonny said:

The problem needs to be cured before I build on anyway! After all the effort I put in, adapting the controls, installing brackets, wiring, installing the servo's, cutting my panel, testing, etc., there is just no way back! Trutrak will have to make this work!

Click to expand...

One thing to think about. Over the years here and on the Matronics forum (I've been reading these for about 14 years); I've seen many complaints against the manufacture, where the actual problem was some kind of a slight error due to the installation. Just last week there was one on this web site, in regards to a Garmin and Icom radio. Turns out the Icom had problems because of a small short due to two wires being too close. The airplane builder had about had it with the radio, but it all turned out well; after getting no where with the Icom rep. Afterall, how's the rep going to know an install error?

I screwed up my own Tru-Trak install, because I wired a "mirror image" on the annunciator light/ power switch. Once I figured out what it was, it works just great. Stein, even sent a free replacement light and plug, which obviously didn't cure the problem.

What I'm pointing out, is that we often figure it's up to the manufacturer to set things straight, no matter what. Yet the problem may or may not be their problem to begin with. Since we install the devices our selves, instead of being required to have them installed by a factory rep; sometimes there is only so much a manufacturer can do. Especially when the installation is far from any representative.

L.Adamson

I wish I was doing something wrong!

"L",

I was assuming it was me who caused the problem, until I heared that a lot of other builders are having exactly the same problem.

I would love to hear that I have done something wrong, than all I need to do is put it right and it will work, right?! I tried so many things, had so many sugestions, but nothing worked, so far.

Please, please, make my day and tell me what I am doing wrong, that is also what I want Trutrak to tell me.

Regards, Tonny

This won't make you feel better, but the RV9A that I flew for many hours before finishing my 6A; also has a TruTrak ADI II, with Coment belly antenna, and a Garmin SL-40 radio along with dual Dynons. It doesn't exhibit any of these pitch problems.

In the mean time, I'll be giving it some thought.

L.Adamson -- RV6A

Tru-Trak

Pilottonny said:

"L",

I was assuming it was me who caused the problem, until I heared that a lot of other builders are having exactly the same problem.

I would love to hear that I have done something wrong, than all I need to do is put it right and it will work, right?! I tried so many things, had so many sugestions, but nothing worked, so far.

Please, please, make my day and tell me what I am doing wrong, that is also what I want Trutrak to tell me.

Regards, Tonny

Click to expand...

Tonny:

I understand your frustration with the current setup.

About 5 years ago when I was dreaming of what I wanted in my panel, I decided on the Tru-Trak Digiflight II VSG and the Grand Rapids EFIS. At the time they were the only ones that could "talk" to each other. I couldn't afford both at the time so I opted for the Tru-Trak and decided to wait on the EFIS.

Two and a half years ago after I completed Phase One Testing, I discovered that with the autopilot on, when I transmitted on the Comm Radio at about 127.000 Mhz and above, my autopilot would push nose down. The higher the freq. --- the more nose down.

I contacted Tru-Trak and they suggested that I shield the "Control Wheel Steering/Auto-pilot disconnect switch". That didn't help.

In their defense, I have an older style stainless bent whip comm antenna with the ring connector; not the BNC style of the later antennas.

I have made sure that the antenna/autopilot signal wires cross at 90* angles where they have to cross.

Since I seldom fly IMC, this is not a very big problem for me. I just anticipate it and hold the stick back when I transmit,as the PTT switch is on the stick of my RV-8.

I have other issues that I've discussed with Andrew and Lucas both of whom promised to get back with me about a month ago and I've heard nothing from them.

Tru-Trak: You need to address these issues and follow up on your promises to call back to avoid further "bad press".

I have stood by you and recommended your products to a lot of people. I'm not trying to "bad mouth" your autopilots. You have a good product, but I believe that you need get on top of this---the sooner the better.

Well said. I'm not interested in bad-mouthing anyone, either - as I said, I bought another one despite the small annoyance.

Really, if your PTT switch is on the stick it just isn't a big deal. Just hold back a bit on the stick while talking. After a while I completely forgot it was an issue. The rest of the time the autopilot was spot-on.

And, it may very well turn out that it was an installation issue all along. Our airplanes are very small, and wires run parallel in many places.

If nothing else, it gives you extra incentive to keep your transmissions short!

breister said:

Well said. I'm not interested in bad-mouthing anyone, either - as I said, I bought another one despite the small annoyance.

Really, if your PTT switch is on the stick it just isn't a big deal. Just hold back a bit on the stick while talking. After a while I completely forgot it was an issue. The rest of the time the autopilot was spot-on.

And, it may very well turn out that it was an installation issue all along. Our airplanes are very small, and wires run parallel in many places.

If nothing else, it gives you extra incentive to keep your transmissions short!

Click to expand...

This is all interesting; but I do have quite a few hours in three different RV's with TruTrak altitude auto-pilots along with PTT switches in the stick, and none have exhibited this problem.

L.Adamson

Hi Guys,

My names been tossed around here a bit since I've been involved with a majority of you on your AP installs. I've kind of tried to keep working this with each of you and do what we can.

However, I thought I would post something publicly to let you know that TruTrak is not ignoring you...quite the opposite. Larry's post actually is what drew me to post.

I know it's aggravating for you if you have these issues, but let me tell you it's hundreds of times (maybe thousands) more aggravating for us a dealers and TruTrak as the mfgr. Here's why. Out of the thousands of AP's that TT has flying, only a statistically very few exhibit these issues. Of those few, we usually find that 99% of the time it is install error of some sort, whether the builder knows it or not. These can be excruciating to troubleshoot, as each installation of each persons airplanes is different, and not being able to be right in front of the plane makes it even harder. I'm not saying it's the case all the time, but almost always in the end it is - what is really hard is to find the trigger for the problem because it can be so remotely far away from the core AP that it just makes it really tough.

Anyway, I don't have much to say to immediately help you, other that to let you know that everyone is looking at each issue when they come up...not much of a warm/fuzzy I know, but it's the best I've got at the moment.

My 2 cents as usual!

Cheers,
Stein

Has anyone an educated guess as to why it's always an issue with the pitch servo and not the roll ? Is this showing up only in certain RV models ?

Most of us here have no intention of bad mouthing TT, and for me, sharing info like this can only help to collect comman facts about the issue and hopefully it will eventualy come to a resloved conclusion.

Wicked Stick said:

Has anyone an educated guess as to why it's always an issue with the pitch servo and not the roll ? Is this showing up only in certain RV models ?

Most of us here have no intention of bad mouthing TT, and for me, sharing info like this can only help to collect comman facts about the issue and hopefully it will eventualy come to a resloved conclusion.

Click to expand...

Yep...it's typically because the pitch servo ends up closer to a transmitting antenna.

It hasn't been model specific either.

Really dumb question...

Is there a way you could temporarily install a new run of coax and an identical antenna - even externally while on the ground - to test the location, cable run, etc? Maybe you have been there already.

More testing going on

Although I said I was not going to do anymore testing, I went to see an Amateur Radio guy today, who works on Aircraft radios occasionally. He suggested that the servo picks up the interference from the coax or antenna (especialy if the antenna is not 100% matched to the radio freqency, which I doubt for a Commant antenna) and sends it back along the wires from the servo to the AP-unit. He said a cure would be:... looping the cable through a ferrite "ring"! Not the coax, but the servo wires! Since the wires are not long anough for looping them through a ring, I picked up a few "sanp-around-two-halves-ferites" from a local electronics shop, to try if they make any difference. If they do, maybe I schould make my wires longer and try the "ring".

Today Lucas sent me an email saying they are trying to duplicate the problem in their shop, to do some more tests. Maybe this will not only solve my problem but also the problems of all the others that chimed in, the last couple of days. Obviously, also Trutrak want to solve this.

Regards, Tonny.

Just a note. Ferrite cores/rings etc. are made from various materials and they are not all the same. You need one that is made for the range of frequencies your working with.

RF traveling back down a feedline is a very common problem with transmitters. Ham's use all sorts of techniques to fight this issue.

Just because your antenna is a Commant does not mean that it will be perfectly balanced across the bandwidth. 1/4 wave antennas like those we use are almost impossible to get 1:1 SWR using coax as a feedline and the airplane as a ground plane.

SteinAir said:

Yep...it's typically because the pitch servo ends up closer to a transmitting antenna.

It hasn't been model specific either.

Click to expand...

Well, considering that my Comant antenna is mounted almost directly beneath the ROLL servo (pitch servo is clear back by the elevator bellcrank), I would expect my setup to have roll interference and NOT pitch by your theory, Stein.

I'll give it a whirl this weekend and report back.

Balun

Tony,
Here is a photo of the balun I used.(befor heat shrink) A Jim Weir design. one he put a awful lot of work in to. if you can tame your Rf I think your problems will go away.
PS. used on the antenna end of the coax

SteinAir said:

Yep...it's typically because the pitch servo ends up closer to a transmitting antenna.

It hasn't been model specific either.

Click to expand...

I have an RV-8. As you know the pitch servo is behind the rear baggage compartment. Distance-wise, the Roll servo is located much closer albeit off to the side.

Mic Key Problem

Pilottonny said:

Today Lucas sent me an email saying they are trying to duplicate the problem in their shop, to do some more tests. Maybe this will not only solve my problem but also the problems of all the others that chimed in, the last couple of days. Obviously, also Trutrak want to solve this.

Regards, Tonny.

Click to expand...

Lucas; Tru-Trak; et al. After Christmas, I'll fly out to AR for a couple of days so you can experiment with my RV-8 set-up to try to determine the problem if you guys will buy the gas and put me up in a Motel that isn't too much of a flea-bag. 770-519-4999.

OK, I went to the hangar today and the first thing I did was flip on the master, turn on the A/P and see what happened when I keyed the mike.

There was a definite pitch down and there also seemed to be some roll effect as well. I tried every combination and found that, with altitude hold off, there was still some slight effect on the roll servo.

Of course, I then referred back to Stein's notes which noted that, "on the bench there was a tendency for the A/P to cause a descending right turn when the mic was keyed," and that TT is aware of the problem and working on a fix.

So, once again, STEIN is absolutely correct (not that I had any doubt).

Also, what that tells me is that the problem is likely NOT necessarily related to the type of antenna, the routing of the antenna coax or the location of the antenna if it happens on the bench as well as in some planes.

Personally, I'm not going to worry about it. My hand's on the stick when I key the mic, so it's apparently not much more than an inconvenience. However, if TT figures out a reliable solution, it would be nice to not have this irritiation.

Mike Key Problem

Guess I shouldn't have had a couple of beers before I made the offer to Lucas to fly to Arkansas. Looks like they may take me up on it.

They have a good product and I'm willing to help solve this glitch. The problem only affects an extremely small portion of their autopilots, and as I suspect, it may possibly be builder error.

Regardless, maybe my being a guinea pig will help keep their customers happy.

(Maybe, they'll feed me a steak too???)

mannanj said:

Regardless, maybe my being a guinea pig will help keep their customers happy.

(Maybe, they'll feed me a steak too???)

Click to expand...

More likely some lettuce leaves.....

AP problem, may be more serious.....

......than you think! Because I want to keep the passenger stick removable, I installed a separate PTT button on the panel, for the passenger. So if the passenger transmits, it may wel be that nobody has his/her hands on the stick, contrary to what some of you are suggesting!

Anyway, I spend more than $ 5.000,- on the AP and it has to work properly!

Regards, Tonny.

Pilottonny said:

......than you think! Because I want to keep the passenger stick removable, I installed a separate PTT button on the panel, for the passenger. So if the passenger transmits, it may wel be that nobody has his/her hands on the stick, contrary to what some of you are suggesting!

Click to expand...

My co-pilot/passenger PTT is on the panel, and it's no problem.....................so there is light at the end of the tunnel!

L.Adamson --- RV6A

More testresults

Hello everybody,

"Andyrv", in a personal message, suggested that I tuck away the coiled up cables that are usually hanging out of the fuselage during construction (wings and tail not on yet). So I packed all these wires in aluminum foil and gues what? Right! problem almost solved! The pitch up is now minimised to one or two notches of the step motor, as where before it was going trrrrrrrrrrr......., all the way back. I can determine now that it even makes a difference where I am standing outside the plane, or when I sit inside.

Then after some more testing, trying some different frequencies, the problem was completely back, exactly as before. How could this be? (the problem is more severe in the mid range frequencies than at 118,00 or 136,00). I suddenly realised that I had hooked up the battery charger, that is sitting under the fuselage, because the battery voltage was dropping during testing. When I Disconnected the Pos. wire from the Battery: problem gone again! (almost). So all the wiring (not just the AP wiring) is picking up interference from the Antenna and passing it on to the AP Unit.

So the problem is definately comming from the radiating antenna, outside the plane, rather than from inside? There is still something to be fixed by Trutrak since 1 or 2 notches of stick movement still means there is something wrong. Also there is people already flying that have the problem (no wires hanging out of the fuse I guess).

A few more things I found during this extensive testing:
- When the unit is turned on for an hour or so, the stepper motor gets warm, not extremely hot, but stll warm, is this normal?.
- The horizontal LEDS's from the left display digit, keep blinking up and down, when the AP is engaged. What does this mean?

Regards, Tonny.

Pilottonny said:

Hello everybody,

"Andyrv", in a personal message, suggested that I tuck away the coiled up cables that are usually hanging out of the fuselage during construction (wings and tail not on yet). So I packed all these wires in aluminum foil and gues what? Right! problem almost solved! The pitch up is now minimised to one or two notches of the step motor, as where before it was going trrrrrrrrrrr......., all the way back. I can determine now that it even makes a different where I am standing outside the plane, or when I sit inside.

Click to expand...

Tony, as someone who has spent some time sorting out autopilots in RV's, may I suggest that you delay spending any more time fixing your autopilot until the plane is actually flying. As you have discovered, glitches that may appear in the shop may have no relevance once the plane is completely buttoned up and flying. I have seen "problems" with an autopilot disappear once the aircraft is out of the hangar, in the air, and subjected to normal aero loading.

You will have plenty of time to sort through any AP squawks once you begin test flights. It is my opinion that to declare "autopilot problems" while the plane is still under construction is most likely premature.

Best wishes for a speedy completion of your project!

WAIT-WAIT-WAIT! We have 4 pages of discussion since your post, people spending time trying to troubleshoot your problem (TruTrak and me both spent our valuable time) and the plane isn't even assembled?!?!!? You have wires hanging out, etc..? I did miss the fact that your plane wasn't flying and that changes everything.

I better quit typing and bite my tongue because I'll say something inflammatory for sure.

PLEASE don't do any more "troubleshooting" on your avionics until you at least get the plane assembled and in the air. You can't possibly troubleshoot how the thing is going to act in the air whilst it's un-assembled in a garage/hangar. It needs to be in the air to know how it acts in the air.

It's far to difficult to even determine if you have a problem or not while the airplane is disassembled and not flying. You may or may not, but wait until she's flyin before you decide.

Stein

Hmmmmm

Pilottonny said:

- What to do/test next?
- My plane is still in the garage (concrete floor with some rebar in it), could the signal be bouncing off the floor, causing this?
- Should the whip of the antenna be ?connected? with the center conductor of the coax? I do not get a reading on my ohm-meter when testing between the whip and the center conductor.


Regards, Tonny.

Click to expand...

Looks like everyone missed this--------I know I did.

Wise decision, Obi-wan Steinobi. No sense starting an international incident over it.

As an aside, I did a little more fiddling today with my AP. And, yes, it's still in the hangar. And the wings are off now. And I have wired dangling out both sides.

I found that, when the alt hold is NOT engaged, keying the mike seems to have NO effect on the AP on any freq that I tried. However, as soon as I engage the alt hold, it starts going wonky when I hit the PTT.

However, since I now have to turn my attention to sanding and priming and sanding and priming and sanding and priming and painting ... I'm not gonna worry about my AP.

Just thought I'd finish my part of the story. Carry on ...

Just a note to everyone who is testing transmissions and PTT's. When done inside a building or hangar or garage, you're likely to get all sorts of wonky things that won't happen in the air. It gets worse if you have random wires that aren't yet terminated hanging around your plane. It's ok to test things, but not necessarily a great idea to start transmitting in your garage/hangar until all the wiring is hooked up. Transponders too!

Cheers,
Stein

Cables

This interference applies to EFIS issues as well. I wasted 3 days of my time but probably only 15 minutes of GRTs time before my wings were on. I had 15 feet of nav/strobe/landing light and antenna coax on the outside of both sides of the fuselage. Because other people were reporting slight interference problems with their EFIS I kept troubleshooting. It was the coils of wires bringing the RF back into the airplane. Moving the wires greatly minimized the problem but I was still concerned.

When the wings were on and all wires terminated all the "problems" were gone!

Andy

Trutrak pitch issues

I had a I-AP, authorized to install a pictorial pilot II in an RV-6. This replaced an existing S-TEC and Altrak. No problems with S-TEC or the Altrak. The first flight to Oshkosh became a pitch nightmare with Pictorial pilot II. The plane went back to the AP's shop for months, no change, hit the PTT and the pitch jumped up. Tried new auto pilot head N/C from Trutrak, new antenna, new radio, connected radio directly to battery, moved harnesses, checked as many shielded wires as possible, new coax RG 400, rerouted it, checked with hand held in the plane and outside of the plane, the problems continued. Moving the antenna seemed to help but not completely.
My final solution, which worked into my long term plans anyway, was to rip out EVERY wire, line, harness, and instrument. I bought the upgrade Digiflight II VSVG along with a full AFS glass panel, so if the problem exists after my total rebuild, I will try another hobby.
Some +'s out of all this frustration is that I have gotten to know some of the smartest and most patient people in aviation. The solution of moving the antenna sounded silly to me but disrupting the line of sight from the antenna to the radio might help. There is a solution and I disagree that you should fix this after the plane is built and flying. Try to get it right on the ground with the plane open because it is easier work on and moving antennas, wires, and cables now, is less work. My 2 cents. Good luck.

My initial question!

Stein,

I am sorry you misunderstood, but my question was actually (my first post in this thread) if this problem could be, because the plane was still in the garage! As a matter of fact, in several posts I commented thad I wanted to get this problem out of the way, before I closed up the front deck, because if anything (wirewise) had to be changed, now would be the time. As you will know, ones the plane is flying, rerouting the wiring is ten times more difficult.

Trutrak are aware of this, apart from this thread ,there was a lot of additional communication with Lucas.

Thanks for you replies anyway.

Regards, Tonny

Hi Tonny,

I now understand your predicament and your desire to ensure that everything works well before you fly. That being said, some things just cannot be accurately tested before the plane flies. The best you can do is take the steps necessary to avoid possible "issues" once the plane is done. Sometimes issues can and do arise, and indeed you are correct that it's difficult to re-route wiring.

The above being said, I hope you can understand what I am saying as well. Spending many hours with yourself and the mfgr and/or dealer such as myself is a tremendous burden on business when we're trying to troubleshoot things with so many variables. Having the airplane unfinished and not assembled makes that job almost impossible....so the fact of the matter is at this point you're spinning your wheels to some extent. That translates into lots of hours, heartache and money spent not just for you, but for everyone involved.

I'm not trying to slam you, just letting you know that at this point the troubleshooting you're doing is likely much in vain because while gross problems may show up at this point, it's fairly likely you cannot replicate the conditions experienced in the air with the plane sitting unfinished in a hangar/garage.

Again, if you do as much prevention as you can in the beginning the end result should be a good plane overall. But, as with everything issues can and do arise. Two weeks ago we spent the better part of a day troubleshooting and RV8 with an AP issue that was extraordinarly difficult to pin down by TruTrak and us. Turns out a bent pin in a connector for the transponder was causing the problems. Tomorrow we have an RV-10 flying in with some weird remote magnetometer gremlins to try and troubleshoot. So, I'm afraid that occasionally despite your best intent and attention, things can and do happen.

The best advice I can give you and everyone else at this point of your build is to focus on doing things properly, using best practices and get the plane done/flying....don't spend time trying to find solutions to problems that may or may not exist. Things work out more often than not!

Have a great week and keep moving forward. Obviously you are a skilled builder who wants to have a nice plane.

Cheers,
Stein

Vendors

Excellent reply Stein.

Your patience with people like me is remarkable. This shows why you have an outstanding reputation in the business and why people keep returning to you for repeat business.

Possible Fix!

Guys & Gals,

One of the regulars on the Lancair Mailing List posted this, and it may cure the problem (Caveat Emptor).

Chris Zavatson said:

I am happy to report that the RF problem I was having with the Trutrak autopilot has been solved. One of the posted suggestions pointed to a filter adapter that is installed between the controller and the harness. I ordered part number FCE17-B25AD-250 from Digikey for about $25 and it cured my system. Not a hint of interference from either radio.
thanks to all who wrote in.

Chris Zavatson
N91CZ
L360std
www.N91CZ.com

Click to expand...

I haven't experienced the problem in my current plane, but if others want to try this and either confirm or deny the fix, I'm sure others would appreciate the feedback.

Oh, and there is now a TruTrak Forum here.

PTT same problem

I also have found TT and Stein to be very helpful, willing, and knowledgeable, but I have not been able to cure this problem in my setup. I also have the Garmin sl40 with the bent whip antenna and have tried many things with no success. I would be very interested in the success of installing the filter block between the harness and ADI head.

With unlimited variables in installations, I'm sure this is extremely hard to pin down, but I will eventually find the gremlins.

On another note...my unit will only use about 10 degrees of bank when turning. Is there an adjustment to steepen the bank with an ADI pilot II that has GPS input? 10 degrees will not cut it with ATC.

Cheers and thanks to all for the posts on this challenge.
Don in PHX

TruTrak PTT pitch solved

I followed the link as previously posted on the filter made by Digi-Key, purchased it, installed it in 5 mins, and it solved my pitch up problem with my PTT. I believe my problem originated with my using a single shield coax instead of a double shielded coax like RG400 on my radio antenna. I did route my coax originally completely separate from all other wiring, but apparently the Garmin puts out a lot of RF. Here is the link and the part cost $27 plus shipping. Good luck!

http://parts.digikey.com/1/parts/1599616-filter-male-female-adpt-25pos-fce17-b25ad-250.html

Don
RV7
PHX

Thanks for the additional confirmation Don!

I tried it too, and noticed a difference. This info is now posted on the TruTrak forum, and I urge anyone who has tried this solution to report their results in this thread on the TruTrak forum.

RF interference

I installed the Vans MP in a tube and fabric plane with the sensor box behind the panel. The MP would go full scale on transmitting. I moved the box only a few inches and the problem went away (mostly). Here the wiring bundles were not an issue.