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Al,
No I was not aware that you went through similar
problems. I was off this forum for about 4 years during which time you completed
your project and flew it.
Your experience seems similar to mine. If anything
yours sounds more severe. Looking back over the past year and a half since I had
my first engine start, I've realized that I've gone through very long stretches
without any of these problems. In fact the first 20 hours of ground run time I
had all of the typical (many self induced) tuning issues, but no cases of
corrupt data that I could identify. It wasnt until after my first flight that I
had it happen. Three times and then I grounded the airplane. In the subsequent 4
months and an additional 5 hours of run time on the ground there were no
instances of corrupt data until this past weekend when I started prepping to
resume test flying. Since then in about 2 hours of ground running I've had 4
instances of corrupt data. Three cases where it wouldnt run on B, but since I
have no way to know whats loaded in B I dont know what exactly is happening
there. And one case of the staging point on the A controller changing to
12".
I could probably resume test flying as long as I
remain over the airport. But given my phase 1 test area and the terrain I'd have
to cross to get to something landable I wouldnt want to venture too far from
Brown Field with it like it is. Whats the point of having a backup controller if
you have no confidence in it?
My EC2 is also an early one. I've had it so long I
cant recall when I bought it! So as you say, newer units may not have similar
issues. And of course in my case since the problem is unresolved at this point,
it may still be an installation issue, though at this point I'm stumped as to
what that issue may be. I agree that the EC2 is the best option for the
application. When not having these problems, the engine runs
great. Which of course is part of the frustration - with it running so good
why cant I go fly it and have confidence in it?
No opportunity to do any further testing today but
hope to get back on it tomorrow. I've sprung an oil leak (previously thought
repaired) that I need to fix before I can start the engine again.
Mike
----- Original Message -----
Sent: Friday, July 03, 2009 1:27 PM
Subject: [FlyRotary] Corruption of EC
settings
Mike;
Mike;
You may recall my
experience with these issues. I fought with spontaneous corruption of
settings for about a year. I could never correlate the occurrence with any
specific operations. Sometimes it would happen between startups, sometimes
during taxi; sometimes in-flight. Tracy’ explanation was
always severe electrical noise. I double checked everything, re-routed
wires, added snubbers, etc. The occurrences became less frequent; but
not did not go away. I never had a case where some adjustment did not
allow fairly normal operation, but it certainly kept me from feeling ‘safe’
during flight over rugged terrain.
I finally elicited
the help of an expert. We put the oscilloscope on all parts of the
system, and on every pin into/out of the EC2, and ran all operating
modes. We found a few spikes we didn’t like; added some more snubbers
and filters on electrical leads; eliminating all of those. We were sure
it would all be fine.
During the next
10-15 hours of flying, and I still had occurrences of pulse width change,
stage point shift, correction table changes. Further work with the
oscilloscope and my ‘experts’ conclusion was he could see nothing beyond that
he considered ‘abnormal’ electrical or RF noises. He then took the unit
back to his shop, evaluated the circuitry, and added filters to the board
where he deemed necessary. The unit has operated fine ever
since.
His conclusion was
that the design was not particularly noise tolerant. My conclusion was
that one man’s ‘normal’ noise was another man’s ‘severe’ noise. Based on
the prevalence of the issue, and nothing else in my airplane, EFIS, digital
compass, avionics, whatever; has ever had an issue, I concluded as well that
there was perhaps insufficient noise tolerance in the EC2.
Let me point out
that mine is an early version of a 3-rotor unit, and the issues may not be
applicable to others.
I’m sure it is
possible that there may be noise issues in my system that we just never
saw. And each system is different. I suspect that is most cases,
Tracy is right; that
there are electrical issues. But it is also clear that further filtering
on the board solved the problem in mine. I’m not suggesting at this point that
you jump to modifications on the circuit boards, but at some point, it’s a
consideration.
I know this is
being critical of the EC2, so Let me add that, before my issues were resolved,
I had to consider alternatives the RWS EC2. I always came to the
same conclusion: that
overall, this was the best option available; and Tracy’s cooperation has
been the best.
After 150 hours TT,
on my last flight the RPM, fuel burn,
read-outs on the EM2 suddenly went to zero during the pre-takeoff run-up
checks. I then sent the data acquisition module back, and
Tracy found “corruption
of the program flash memory”, and; “only known possibility is severe
electrical noise”. Oh, well.
Al
G
-----Original
Message-----
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills
Sent: Friday, July 03,
2009 7:50
AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: frustrating
couple of days
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.
----- Original Message -----
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?
Let me know if you think of something I
can do to help.
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.
----- Original Message ----- From:
"Jeff Whaley" <jwhaley@datacast.com>
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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