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Out of phase 1 positives and negatives

allbee

Well Known Member
I made it. Took me 18 days. I'm off the leash...

With that said, my positive and negative of the airplane are as follows.

Negatives.

I had issues with the charging system, the plane power alternator needs more than a 5 amp fuse. I ended up putting a 20amp, as per aeroelectric.

I drilled a single hole in my panel and the scrap went right into my radio, there was a single hole that was right under where I cut. The shavings went and shorted out the radio, couldn't transmit. I pulled the radio and out dumped all the shavings, reinstalled the radio, now it works great. Leason, cover things when doing any cutting.

After 15 hrs I had the injectors plug up and needed to do a turn back on takeoff, an ultrasonic cleaning made things all better.

The elevator is stiff, exceptable on the ground, maybe some restriction from the ap, but just fine. It's the forces of flight that make it hard, generally over 150mph. Aileron is perfect, nice. Elevator takes some force to change altitude, up seems easier than down, that's probably do to center of gravity. Even so either way is much stiffer and will take a little to get use to. The RV6 is much easier in this department.

I have to say, Jamie, your complaint on the AP is justified. I think the AP is a piece of XXXX. I've tried everything, sensitivity, up, down, doesn't matter, it won't hold on an altitude and mainly role for nothing. Occationally I can get it to do ok on the pitch, but that roll, forget it, it overshoots the course at least 10degrees, if I increase the sensitivity it wing wags as it goes on course, as it gets close the wag stops and than it bypasses than and does it all over again. I've tried everything. If I have everything zero'd on the trim and flying straight and true and level. I hit the auto it feels like I just went into turbulance. I think the problem is programming, either in the servo's, efis, or both. There is nothing wrong with my install or controlls, there rock solid. I can actually see and feel the stick being moved all over with the auto pilot. I have 5.1 in programing. Oh I called Dynon and I must have gotton a bad day for mike, way rude.

Nother complaint on the Dynon efis, the fuel flow shows too high on fuel rate and it occationally drops to .1 than back up to 12 in cruise. I'm not burning that much. I have mine installed like there pic right in front of the afp fuel pump. I have fuel injection, XP360.

On the dynon again, occationally I get a sensor that will turn red, like the oil temp and it says 185, not where I have the red zone at all. My warning light doesn't come on, but it's blinking red. Than it will quit. All I can say is WHAT?

Things I like.

My engine is cool. Works great.

My prop is cool. Again works great.

My steam gauges are cool. I can count on them.

My govornor for the prop is cool. right on the money, works great.

My garmin 696 is way cool, big screen, can count on that also.

Love my tipup, vis is outstanding.

Other than the stiff elevator control, I love my airplane, way cool.
 
Other than the stiff elevator control, I love my airplane, way cool.

Congratulations on getting off the leash. That is no small feat.

Something is wrong with your elevator system somewhere along the line. The control harmony in these planes is just fantastic.

Is it a binding feel or an airload type of feeling? I would disconnect the AP linkage to the elevator as a start regardless of the feel. Good luck and again congratulations.
 
It's more of an airload feel.

I can disconnect the ap, since I'm not to thrilled with it anyway. TRy it.

I also thought of disconnecting each elevator to check for movement and balance, just in case.

thanks.
 
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Pitch feel will definitely vary with CG Steve (as you probably know) - the further aft you are loaded, the lighter it will get. If the load you feel increases with airspeed, I doubt that it is a problem in the system (friction, or binding), but everything is worth checking.

Did you do full CG-range testing, and did you notice a difference?

Paul
 
thanks paul for chipping in.

I went out and checked the elevators with the rod disconnected and do feel resistance, I'm thinking from the bearing that joins the two elevators. I loosened the bolt and seems it got better. I'm thinking of loosening the bolts that hold the bearing to see if it needs to center itself, maybe. More later on that.

On flight testing for CG. I did notice stiffer elevator when I was full fuel versus half fuel. I will be having my wife in the right seat, so that should give me some aft weight. See how that works out. I seem to think the elevator being on the stiff side might be my problem though.
 
I went out and checked the elevators with the rod disconnected and do feel resistance, I'm thinking from the bearing that joins the two elevators. I loosened the bolt and seems it got better. I'm thinking of loosening the bolts that hold the bearing to see if it needs to center itself, maybe. More later on that.

All the bearings in the RV control system (at least on my 6A) work on clamp-up. Should work better when clamped up to proper bolt torque as it guarentees rotation on the bearing and not the shaft (bolt). Make sure that you have proper spacers (washers or those short peices of alum. tube) to not bend the ears of the clevis. Deformed clevis could cause it to crack or bind.
 
Love my TruTrak

Not trying to be a smart *** but all I can say is I sure love my Trutrak autopilot. Most others with TruTrak systems seem to feel the same way.

Sorry you are having troubles with your Dynon. I too have called Dynon on occasion when they were "having a bad day"

Sounds like possible misalignment of the drilled hole through your two elevator horns to the bearing.

Ted
 
Just a quick comment on the AP roll performance. Until you go through the DYNON electronic compass calibration procedure, the AP will not function well at all in the heading or course mode however It should function fairly well in NAV mode. So, if your testing has been in the heading or course mode and you haven't calibrated you compass yet, do that and try the AP again.

As for the AP pitch performance, mine only works well in very calm air, actually the same can be said more or less for the roll performance. I'm also not very happy with the overall DYNON AP performance.
 
Just a quick comment on the AP roll performance. Until you go through the DYNON electronic compass calibration procedure, the AP will not function well at all in the heading or course mode however It should function fairly well in NAV mode. So, if your testing has been in the heading or course mode and you haven't calibrated you compass yet, do that and try the AP again.

As for the AP pitch performance, mine only works well in very calm air, actually the same can be said more or less for the roll performance. I'm also not very happy with the overall DYNON AP performance.

Now that you mentioned the compass, I've calibrated it twice now and seems to work on one direction ok than I turn to another direction and it's off up to 20degres. The north direction seems ok, than going south it goes bad. I have it mounted on the external just behind the bulkhead that I have the Experimental sign on. Could be the unit is picking up interference. Might have to put a barrier around it like a regular compass, or find a new spot.

I have been trying to get it to hold course on the NAV, but all others are a mess as well.
 
All the bearings in the RV control system (at least on my 6A) work on clamp-up. Should work better when clamped up to proper bolt torque as it guarentees rotation on the bearing and not the shaft (bolt). Make sure that you have proper spacers (washers or those short peices of alum. tube) to not bend the ears of the clevis. Deformed clevis could cause it to crack or bind.

THis made me think a little, I remember trying to get the right amount of shims on the bolt to the brackets. I remember tightening the bolt and found I needed more shims, when I removed the bolt afterwards it seemed to be a little hard to remove the bolt, but not impossible, it might be that the horn is just a little out of alignment and needs to be straightened and more shim put in to make it straight again. Hummm... something to look at, thanks.
 
Stiff Elevator

Have you sighted down the trailing edges of the elevators (with the rudder removed) to make sure they are lined up and also that they dont have a twist in them?
 
Have you sighted down the trailing edges of the elevators (with the rudder removed) to make sure they are lined up and also that they dont have a twist in them?

I do have a misalignment, I called vans on it and they said it won't cause any issues. The right aileron is lower than the left, leveled the fit is, left higher and right lower about 1/8 on each side. To fix, I would have to either, remove the right aileron and fill the hole, redrill. Or get a bearing in the back for an an4 bolt and redrill to a bigger bolt. Like I said, vans said this won't do anything, but I'm in wonder on that one because I do have a left heavy wing and I have a thought that it would kill some speed, not knowing how much of course. But would that affect some drag and cause a heavy imput on the controlls, don't know, anybody.
 
I would guess that the alt hunting on the autopilot is related to the stiff elevator. Fix the stiff elevator and your autopilot altitude will probably be OK. And it sounds like you?re on track there with the bushing. Also, if you haven?t done full aft and full fwd cg tests as part of your test routine, I would consider it. All flight regimes should be tested as part of phase 1. There are several checklists out there listing the items that should be tested. It pays to be methodical here. Good luck!

Aaron
 
another thing to check

is the bend radius at the trailing edge of the elevators. The fatter or more rounded it is, the lighter the controls feel. If the trailing edge is bent too tight, it will cause a heavy feeling in the controls. If you have the -9 rudder which tapers at the trailing edge, I noticed it is much stiffer feeling than the original -8 rudder which was rounded.
 
is the bend radius at the trailing edge of the elevators. The fatter or more rounded it is, the lighter the controls feel. If the trailing edge is bent too tight, it will cause a heavy feeling in the controls. If you have the -9 rudder which tapers at the trailing edge, I noticed it is much stiffer feeling than the original -8 rudder which was rounded.

To bad I didn't know this when I built the elevators. I thought I was doing good by making a nice sharp bend on mine. This might be it. thanks.
 
Just a quick comment on the AP roll performance. Until you go through the DYNON electronic compass calibration procedure, the AP will not function well at all in the heading or course mode however It should function fairly well in NAV mode. So, if your testing has been in the heading or course mode and you haven't calibrated you compass yet, do that and try the AP again.

As for the AP pitch performance, mine only works well in very calm air, actually the same can be said more or less for the roll performance. I'm also not very happy with the overall DYNON AP performance.
Stand by for the next software update. Dynon just keeps improving things.

Also, I highly suggest you contact Dynon regarding your AP performance. They should be rock solid.
 
THere was a manufacturing error on my elevator horns

The elevator horns on my RV-6A elevetors were off by a lot.I had to fill the gap with spacers and I bolted an aluminum rigidizing link block between the two horns with AN3 hardware about half way between the elevator pivot axis and the pushrod connection. There should be no detectable binding if the rigging is correct. Mechanical binding that seems OK on the ground will get your attention in the air. I recently modified my ailerons by plugging the recesses in the ends with balsawood basically and I drew in my builder's/modifier's log the exact location of each piece of hardware on the pushrod to aileron link to avoid any reassembly problems. As it turned out I managed to mislocate the hardware on one aileron so that the rod end bearing shank was riding on the edge of the large diameter washer. On the ground it seemed normal in the preflight "controls free and correct" check but when I flew the plane it flew, as I described in this forum, "like a pig". When I located the problem in the post flight inspection I corrected it and it flew with that delightful roll response that we all know and love. Since you detected resistance in your ground check I think you have a similar problem in your pitch system.

My autopilot is Tru Trak and it works perfectly.

Bob Axsom
 
Second Bill's comments. Dynon will make it right. They are cutting their teeth on how to write code for an AP. Everyone that bought into their unit knew this and it will take some time for them to get it correct. The good news is that they put together some awesome concepts with the smart servo's and such so once they figure out all the code issues, this thing will rock!

TruTrak is great and have been for a long time but I know for a fact that when they first started making AP's they had their share of learning and debugging to do as well.

Dynon is not perfect but they do offer a great value with great promise for the future and they will make good on delivering a solid AP.

I also stand in line with those that say there should be absolutely no binding in the elevator on any RV. 90% of the time you fly these things with your finger tips using micro movements and if there are any binding issues, this will show up as poor handling and can do nothing but harm any AP's smoothness.

Stand by for the next software update. Dynon just keeps improving things.

Also, I highly suggest you contact Dynon regarding your AP performance. They should be rock solid.
 
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As for your Dynon it sounds like you have a bad ground. My fuel flow would drop out every once in awile and I finally grounded it directly to the ground bus and have had no problems since. I also ended up grounding all of the Dynon grounds to the bus and my unit has worked flawlessly for 100hrs so far. That might be the source of the autopilot problems. Don
 
Here is the thread describing my problems with the Dynon AP that Steve was referring to.

Honestly I think the area where Trutrak has an advantage here is....they have their own airplanes to test in! They write some code and go and fly it. Change it again, go and fly it, etc. They are not 100% dependent on beta testers to give them feedback. Sorry, but beta testers,verbal descriptions and 1 second resolution log files are only so good. Your rear is a much better judge of how the AP actually flies.

Dynon will get it to work (eventually), but I simply didn't have time to sit around and wait for them to do it. The vibe I got from them basically was that something was screwed up with my airplane, but I pretty much eliminated that possibility when the Trutrak worked flawlessly on the first flight using the same servo mounts, the same pushrods, etc.
 
Jamie your right on with the first part of the post. AFS is another company that uses this method and it really shows in their product.

When it is all said and done, I bet your exact situation will end up helping Dynon reach the end goal. Your experience has forced them to realize that they have more work to do in their code. After all, if TT can do it, they can to if they work hard enough to figure out the code behind it.
 
Congratulations on getting off the leash. That is no small feat.

Something is wrong with your elevator system somewhere along the line. The control harmony in these planes is just fantastic......

First of all congrats on building and flying your airplane, that is no small feat in itself. You've moved on to a very exclusive club of pilots.

You are making a huge effort to resolve the issues that surfaced during phase one testing by writing of the them here, that's very proactive and good. The responses have been right on.

There is not much I can add except I agree completely with Hugh on control harmony. I've flown in 7 different RV's and they all have been a delight with regard to elevator-aileron smoothness and harmony. Something is not right about your airplane and it probably has to do the elevator bell crank, the hinges or the elevator shape itself.

The auto pilot stuff I view as important in the beginning as cosmetic issues . Disconnect it and resolve the flight control problem. The elevator stiffness is serious and has to be fixed even if it involves building new elevators.
 
As for your Dynon it sounds like you have a bad ground. My fuel flow would drop out every once in awile and I finally grounded it directly to the ground bus and have had no problems since. I also ended up grounding all of the Dynon grounds to the bus and my unit has worked flawlessly for 100hrs so far. That might be the source of the autopilot problems. Don

I have mine hooked to the ground buss also. now today it didn't drop out at all. go figure.
 
Here is the thread describing my problems with the Dynon AP that Steve was referring to.

Honestly I think the area where Trutrak has an advantage here is....they have their own airplanes to test in! They write some code and go and fly it. Change it again, go and fly it, etc. They are not 100% dependent on beta testers to give them feedback. Sorry, but beta testers,verbal descriptions and 1 second resolution log files are only so good. Your rear is a much better judge of how the AP actually flies.

Dynon will get it to work (eventually), but I simply didn't have time to sit around and wait for them to do it. The vibe I got from them basically was that something was screwed up with my airplane, but I pretty much eliminated that possibility when the Trutrak worked flawlessly on the first flight using the same servo mounts, the same pushrods, etc.


Jamie,

I take it the resolve for you was to rip out the dynon and install the trutrak. What a pity. I originally had it planned out to do the trutrak as well. I got switched over because I thought an AP with efis would be cool. NOT.

I put my wife in the plane last night for the first time and when I turned the AP on, my wife said what happened? I said I turned on the AP, she said, turn it off, you fly so much better. I thought it was working good for what I've been having. She said it felt like we just went into turbulance.

Now onto my elevator, it's fixed, I found that I did squeeze the control arm on one side a little from lack of shims. I corrected and added a shim or washer. Now it's fine, the elevator is a little stiff, at least more than my kitfox, but very doable now, the trim works much better as well. THe AP, still varies 200ft per min eather way, some times it stays fine, than it goofs. The roll, well, not to bad, but could be better, I have the sensitivity down to 5. It has a variance of 5 degrees, in other words it drifts 5 degrees and than tries to correct. Don't talk about the NAV, man what a mess. You have to be locked right on with the goto line, if not, it will bank to pick it up, overshoot and do it again. You better get right on the line before hitting the active button.
 
AP issues

We get A LOT of AP issues stemming from loose control cables. Anyone feel free to correct me if RV's don't use cables for I've never worked on one let alone have my own yet. Either way, we correct loose control cables all the time for exactly the problem you are describing. Just a thought...
 
We get A LOT of AP issues stemming from loose control cables. Anyone feel free to correct me if RV's don't use cables for I've never worked on one let alone have my own yet. Either way, we correct loose control cables all the time for exactly the problem you are describing. Just a thought...

RVs are all push-rod except for rudder.
 
Now onto my elevator, it's fixed, I found that I did squeeze the control arm on one side a little from lack of shims. I corrected and added a shim or washer. Now it's fine, the elevator is a little stiff, at least more than my kitfox, but very doable now, the trim works much better as well.

When everything in the elevator control system on an RV is proper installed and adjusted, you should be able to flip an elevator and have it bounce back an forth between the control stops a couple of times (with any installed autopilot servo disconnected).

If an RV's elevators wont do this, the handling qualities are reduced and the pitch trim stability is probably reduced as well.
 
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