Ver 11 issues?

[swatson999]

So I noted the following issues earlier:

Brief red "Xs" on certain devices during startup
Audio initial check "Dynon Skyview" cuts out partway (drops middle of "Dynon" word)

Today I saw two additional issues, not sure if they're related or not

After around 230 hours of perfect behavior, my #2 CHT went bad...low values (70-130 or so), jumpy, even went negative.

Once or twice during climbout, RPMs jump up 200 or so (above 2800, which I *kinow* is not correct) for just a fraction of a second.

Not sure what's going on here, but I don't believe in coincidence...a CHT that's been perfectly fine for hundreds of hours fails within 1 hour of a new firmware install? An RPM gauge and display that's never acted up *once* during all that time suddenly shows weird values?

I'm fixing to go on a cross-country Friday, so I'll check out the CHT probe and perhaps swap it with a replacement that I have for just such an occasion, and I'll double-check the RPM connections to the mags...but if this is related to V11 and it messes up my trip, I'm going to be one unhappy camper...

 

[jakej]

Steve
1. CHT probes don't play up usually however if there are bad readings then they are, also usually, caused by the connections to the probe wire - you MAY have the issue due to vers 11 but lets wait & see
2. You know there used to be a time when a lot of planes had only 1 CHT/EGT probe, personally I wouldn't let those issues you have stop me from flying - you may have a different view & I respect that. I hope it all works out ok

Jake J

 

[swatson999]

Steve
1. CHT probes don't play up usually however if there are bad readings then they are, also usually, caused by the connections to the probe wire - you MAY have the issue due to vers 11 but lets wait & see
2. You know there used to be a time when a lot of planes had only 1 CHT/EGT probe, personally I wouldn't let those issues you have stop me from flying - you may have a different view & I respect that. I hope it all works out ok

Jake J

CHT I wouldn't care about...RPM, though, is a different question. It's required by law, and I would be pretty uncomfortable flying a plane with a CS prop where I didn't know what my RPM was...

 

[preid]

On the io540 I have had the prop overspeed on takeoff randomly triggered but never an issue at lower RPm's, this is probably due to the resistors between the mags and the mag switch. The prop is at 2700rpm. Is a display issue
Does the rpm go rampant at different rpm ranges?

 

[swatson999]

No, it was fine the rest of the flight and has *never* "oversped" on the display, ever. Also didn't act up during runup, cruise, descent, etc. Only during initial climbout...did it once or twice, but it got my attention (although there was clearly no actual overspeed...).

What bothers me is that it's been *perfect* for over 200 hours, but within an hour or so of uploading new firmware, this strange behavior exhibited itself.

Like I said, I don't believe in coincidence...

 

[jakej]

Steve
Thanks for the extra bit of info - I have a customer with exactly the same rpm symptoms, it only acts up at the high power takeoff rpm (IO-540 in RV10) - am waiting to get a chance to fit the P-Tach that Vern Little designed as I believe it will fix the problem permanently.

Jake J

 

[Dynon]

So we haven't received many (maybe any other) EMS performance issues tied to 11.0. Generally, and I appreciate and don't discount that there could be something software-related here (though I have my doubts), CHTs that are erratic are tied to the connection, and RPM that is spiking high can use a big higher resistor if we're talking about the normal p-lead pickups on a Lycoming or Continental with normal mags. That said, if you can get a diagnostics log of the behavior within an hour of it happening, we can take a look and see if we can see what you're seeing. We'll PM you instructions.

 

[jakej]

Steve
Thanks for the extra bit of info - I have a customer with exactly the same rpm symptoms, it only acts up at the high power takeoff rpm (IO-540 in RV10) - am waiting to get a chance to fit the P-Tach that Vern Little designed as I believe it will fix the problem permanently.

Jake J

I should say that his rpm issue was from before vers 10

Jake J

 

[swatson999]

Update: decowled and fiddled with the CHT sensor; seems that it might have been at the connector...disconnected, reconnected and it seemed fine, so we'll see.

As for the RPM, though...that's worked perfectly since day 1 until yesterday with the stock/standard resistors...never a hint of a problem, ever.

I have the log file, will examine it in Savvy Analysis and see what it shows.

 

[preid]

Steve
Thanks for the extra bit of info - I have a customer with exactly the same rpm symptoms, it only acts up at the high power takeoff rpm (IO-540 in RV10) - am waiting to get a chance to fit the P-Tach that Vern Little designed as I believe it will fix the problem permanently.

Jake J

I should say that his rpm issue was from before vers 10 

Jake J

yes, I agree I had it from version 1 or whatever the first version I used for my RV-10. The resistor is like 1.5K or something and if the stars are aligned in the middle of the day it will spike on takeoff, than not for a while.

 

[swatson999]

OK, here's what the data show:

Session Time, RPM L, RPM R

756.25 2625 2625
756.31 2624 2624
756.38 2624 2624
756.44 2624 2624
756.5 2624 2624
756.56 2858 2858
756.62 2858 2858
756.69 2858 2858
756.75 2858 2858
756.81 2623 2623
756.88 2623 2623
756.94 2623 2623
757 2623 2623
757.06 2628 2628
757.12 2628 2628
757.19 2628 2628
757.25 2628 2628
757.31 2625 2625
757.38 2625 2625
757.44 2625 2625
757.5 2625 2625
757.56 2624 2624
757.62 2624 2624
757.69 2624 2624
757.75 2624 2624
757.81 2621 2621
757.88 2621 2621
757.94 2621 2621
758 2621 2621
758.06 2618 2618
758.12 2618 2618
758.19 2618 2618
758.25 2618 2618
758.31 2619 2619
758.38 2619 2619
758.44 2619 2619
758.5 2619 2619
758.56 2619 2619
758.62 2619 2619
758.69 2619 2619
758.75 2619 2619
758.81 2856 2856
758.88 2856 2856
758.94 2856 2856
759 2856 2856
759.06 2619 2619
759.12 2619 2619
759.19 2619 2619

All other data values are nice and smooth...no variance in amps, oil pressure, etc. Obviously, the RPMs didn't jump by >200 in a fraction of a second, then back to normal...twice...and then back to normal. Never seen before, didn't happen afterwards on the flight.

Possible explanations?

 

[jakej]

Steve

Our experience puts it down to the magneto, can't explain how but another guy had same problem & tried another mag & problem went away.

The first RV10's rpm issue happened after the mandatory 200 ? hr service, was ok up until then.

If you want it perfect then I'd go with Vern's P-Tach unit available from http://store.makerplane.org/magneto-p-lead-tachometer-signal-stabilizer-p-tach/

Jake J

 

[swatson999]

Steve

Our experience puts it down to the magneto, can't explain how but another guy had same problem & tried another mag & problem went away.

The first RV10's rpm issue happened after the mandatory 200 ? hr service, was ok up until then.

If you want it perfect then I'd go with Vern's P-Tach unit available from   http://store.makerplane.org/magneto-p-lead-tachometer-signal-stabilizer-p-tach/   

Jake J

I'd rather find the source of the problem first before throwing solutions at it...since it's been perfect up until now

That does look like a nice little box, though.

 

[Dynon]

Steve - We have your log via email - we'll reply there with further questions.