Al,
Do you know of any
alternatives out there now that might be worth a look?
Bryan
Preparing to commit $$$
to EC
Bryan;
I haven’t looked any further since
prior to the final stages of getting my EC2 working. The basic issue
(besides cost) is always that the systems are set up for automotive use, and
although they may be noise tolerant, have complexities that make them awkward
for aviation use. And there is the issue of redundancy. Tracy had good reason for
developing his own.
Al
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Al Gietzen
Sent: Friday, July
03, 2009 4:28 PM
To: Rotary motors in aircraft
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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Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
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