flyrotary@lancaironline.net Mailing List Archive

Dave,

Thanks for the offer and the input. Swapping my EC into your plane would be a desperation last move due to all of the hassles involved. And as you say would not necessarily prove anything.

I said it happens when I'm preparing to fly, but that isnt entirely accurate. It would be more accurate to say that in the past it has happened only when I have switched to the back-up controller which usually occurs in prep for flight. This past weekend I had fired it up and taxied down to EAA for lunch. After lunch I taxied back to my hangar and prior to shutting down I ran the engine up to about 3000 RPM and switched to the B controller. The engine died and I had to copy the A program to B to get it to run on B. Switching to B was the only pre takeoff checklist item I performed.

I think about the only thing you hit on here that might be related is heat. But hard to say without more instances of failure and a way to link cause and effect. On saturday when the engine quit on B the engine was completely cowled. On sunday when I had the second instance of an engine quitting on B, the upper cowl was off but the lower was on. When the staging point was lost the upper was off, lower on. Yesterday when the engine quit on the first attempt at switching to B the engine was completely uncowled. Maybe I'll run it up a few more times today uncowled and if it works OK, try putting the cowl back on and see if I can induce failure. Doesnt seem likely though that anything under cowl could cause this sort of problem.

This may all have to wait until Tracy weighs in with his opinion. I'm not inclined to make drastic changes until I hear from him.

Thanks,

Mike

----- Original Message -----

From: David Leonard

To: Rotary motors in aircraft

Sent: Thursday, July 02, 2009 9:28 PM

Subject: [FlyRotary] Re: frustrating couple of days

Bummer that it is not more consistent.... that really makes it hard!.

I would like to help. If youj want, someday I can fly down and we can put your EC2 in my plane and see if we can reporduce the issue. (I'm not so keen about putting mine in your plane I have to admit.) Unfortunately, sounds like even if we can't get the issue to occur in my plane, we still haveent proved anything because it is so intermittent....

You mention it happens more when you are prepairing to fly.. maybe it is something else that you do when you are about to fly besides just switching and checking the B controller. Turning on Strobes? checking injectors? checking lead/trail sparks? checking backup fuel pump? Some GPS or other avionics? Fuel tank selection? canopy closed switch? Some particular engine paramiter? Using the brakes? Temperature change by being in the sun? Cowl in place? Using the Nav/Comm? Headset plugged in? Something else? A combination of 2 or more of those above (eg, plugging in headset, transmitting on comm, and switching to B for example?) Can you make it occur more reliably if you taxi out just as if you were going to fly?

Good Luck Mike,

Let me know if you think of something I can do to help.

Dave

On Thu, Jul 2, 2009 at 7:57 PM, Mike Wills <rv-4mike@cox.net> wrote:

Without knowing details of Tracy's design, hard to say what the real consequences of relocating the switches is. Tracy did explicitly state in the manual I got with my EC2 that relocating the switches is an acceptible option. In any case relocating the switches should not result in any sort of a "ground loop".

Nothing much to report today. On my first start today the engine quit when I switched to the B controller. I had to do a A > B copy to get the engine to run on B. Test ran for another 1.5 hours or so with multiple starts, toggling back and forth between A and B, but could not force it to fail again. Which is kinda disappointing. But thats the nature of an intermittant, isnt it?

About the only thing I can report is that the engine runs richer throughout the RPM range on B than it does on A. A is setup so that its at stoich with the mixture knob at 12:00. On B the mixture knob needs to be at 9:00 for the same indication on the mixture gauge.

Mike Wills
RV-4 N144MW

----- Original Message ----- From: "Jeff Whaley" <jwhaley@datacast.com>

To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, July 02, 2009 10:07 AM

Subject: [FlyRotary] Re: frustrating couple of days

I believe the ground for the controller unit is made through the DB15 wire harness to the EC2; by moving the A/B switch you will have lengthened this ground loop ... maybe try a wire from Controller PCB common to ground of remote A/B switch.
Is it possible for you to put the A/B switch back to original position?
Jeff

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Thursday, July 02, 2009 12:53 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: frustrating couple of days

Mike, per discussion about possible de-bouncing problem. Might try sticking
a 0.01 ufd capacitor from your Controller Switch to Ground - just to
eliminate debouncing as the potential problem.

Ed

Ed Anderson

Rv-6A N494BW Rotary Powered

Matthews, NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.rotaryaviation.com/Rotorhead%20Truth.htm

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Mike Wills
Sent: Thursday, July 02, 2009 12:09 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: frustrating couple of days

Minor correction. Its not that I'm only seeing a problem with the B
controller. Its that it appears that the problem occurs when I switch to B,
but in the 2 cases where the staging point was corrupted, the corrupt data
was on the A controller.

I've been all through the power and ground system. Multiple times. When I
first noted the problem and emailed Tracy about it he suspected ground
noise. After describing my electrical system to him he made two suggestions:
1) I implemented a single point ground even though I have a metal airframe.

I wanted to avoid ground currents getting into the radio and intercom. Due
to CG issues my batteries ended up in the baggage compartment so the ground
connection from the batteries to the single point ground ended up being
about 8' of #0 cable. Tracy recommended eliminating this cable and tying the

battery ground terminals to chassis ground as close as possible to the
batteries. I've done this.
2) My ignition coils were also connected to the single point ground through
about 3' of #14 wire. Tracy indicated that the coils are the greatest
potential noise makers on the airplane and recommended grounding this to the

airframe or engine block as close as possible to the coils. I've done this.
I've reviewed all of my wiring to make sure that things that should be
shielded are and to be sure that noisy wires are seperated from sensitive
ones. There were no obvious problems found in my original install in this
regard, but I did move a couple of wires to gain even more seperation.

So as I said, I believe the power and ground system in the airplane are
sound. I doubt that remoting the A/B switch, or something wrong with the
switch itself, is what is causing this, but I do believe that something is
going on in the act of switching from A to B that is causing the problem.
I'll try to force it in my testing today.

Mike Wills
RV-4 N144MW

----- Original Message ----- From: "thomas walter" <roundrocktom@yahoo.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, July 02, 2009 7:26 AM
Subject: [FlyRotary] Re: frustrating couple of days

Ed,

Odd electrical trivia. Older eeproms were rated at 3.3V, so below 2.7V
they ignored any read or write information.

We had a uC that would start "jabbering" on the data and clock lines when
power was caming up. Since reset occurred once power was good, it was
never an issue. Problem is the eeprom manufactures started shipping parts
that were functional from 1.8V to 3.3V. So once power was at 1.7V, it
accepted writes, corrupting the eeprom. Just to drive the engineers crazy
only some lots and some devices 'jibbered' away. Yes, amazing I still have

any hair left. :)

That is pretty rare, but has happened.

Yes, Mike -- Interesting you're only seeing an issue with the "B"
controller. Still triple check the power, grounds, and rest of the
connections.

Since the fuel map is stored in non-volute memory, it's hard to figure out

how it is being re-written or destroyed. Normally (as you know) access to
EEPROM on a chip is a rather non-trivial process. Since the A and B
controller are two different chips, I suppose there could be a problem
with the B chip - but, while that does happen, it's pretty rare. Have not
had one myself (yet).

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David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net