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Thanks for the feedback Tracy. Again, this is just a
matter of familiarity. Given that most of us are used to adjusting mixture by
cranking repeatedly on the big red knob, it does take a little mental adjustment
to get used to the small adjustments needed with the EC-2. But I'm pretty well
dialed into it now.
Mike
Sent: Monday, January 04, 2010 7:13 AM
Subject: [FlyRotary] Re: first flight of the new
year
I know what you mean about the range on the mixture control
Mike. With just about any setup, full clockwise on it will give you a
too-rich miss. I have considered reducing the range on it but wanted to
make it possible for a builder to rapidly dial in a usable mixture no matter how
badly the map table or injector flow rate was set up. It also gives a clue
as to when these other things are set up OK. When they are right, the
engine will miss at both ends of the mixture knob setting, too lean on the
bottom and too rich at the top. My best power mixture is reached with the
mixture knob set around 2:00. Lean cruise is around 10:00. Full CW will
make it miss every time.
BTW, this characteristic gets even worse when
bigger injectors are used. That's one reason I discourage their use.
I'm getting ready to try a reduced mixture range on my 20B. It has the
stock big turbo (550 cc) injectors and makes the mixture setting touchier than I
would like.
Tracy
On Sun, Jan 3, 2010 at 9:38 PM, Mike Wills <rv-4mike@cox.net>
wrote:
My comment wasn’t intended to be a criticism - as I
said I considered it an operator error. This comes down as a matter of
learning the operating characteristics of my installation. Obviously
with a system as tunable as the EC coupled with so many variations in engine
configurations, each is going to be different.
I'm sure there is more tuning/tweaking that I could do
to optimize operation across the full power band. But right now things are
working pretty well and I'm content to fly it as is and learn the
idiosyncrasies. The fine tuning can come later.
As for full rich during takeoff/landing, in its
current tune my engine will misfire (too rich) if set to full rich during the
descent. I've found in my test flying to date that there are quite a number of
power/throttle settings where the mixture knob has too much dynamic range -
i.e. at some power/throttle settings going either full rich or full lean on
the knob will cause misfire. Again, not a criticism, just a matter of learning
proper operation of my particular installation.
I havent had to execute a go-around as of yet, but in
all of my testing to date, sudden application of full power from a low power
setting hasn’t caused any problems yet. Time will tell...
Mike
Sent: Saturday, January 02, 2010 12:18 PM
Subject: [FlyRotary] Re: first flight of the new
year
I can't really know what the whole story is on Mike's engine
characteristics (a lot of it depends on how the EC2 is set up, tuned and
operated) but keep in mind that the EC2/3 is an open loop system with none of
the benefits of feedback from the O2 sensor. It was never intended to be
a FADEC type single lever power control that many expect. It was
assumed from the start that airplane builders would be familiar with mixture
control requirements of aircraft engines so would not mind similar
requirements when running EFI in an experimental. In a typical GA
aircraft, it is normal to set the mixture to rich (best power) on
takeoff and climb-out, then lean the mixture in cruise for better fuel
economy. It can be leaned even more at lower power settings (ie in
descent) to eek out the last MPG and I do that myself out of
habit. But when it is time to land, it is altogether normal (and
necessary) to set the mixture back to rich when entering the pattern. If
not, you can fully expect the engine to sputter a bit if the throttle is
advanced for a go around. Tracy Crook
On Sat, Jan 2, 2010 at 2:01 PM, Bill Bradburry <bbradburry@bellsouth.net> wrote:
Maybe so, but it seems no farther than it is in the
car and that has to work quicker than it does in our app. Cars don’t
go all squirrely when you coast down a long hill??? We all need broad
band sensors so we can tell what is really going on. I am hoping that
Ed will get upset by all this and build one we can buy from him for about a
buck! :>)
When can we expect the prototype,
Ed??
Bill B
From:
Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills
Sent: Saturday, January 02, 2010 12:16
PM
To: Rotary
motors in aircraft
Subject:
[FlyRotary] Re: first flight of the new year
My exhaust header is an equal
length type with 28" inch primaries into a 2 -> 1 merge collector. The O2
sensor is threaded into the collector so I estimate it is about 36" from the
exhaust port. It usually takes about a minute for the readings to settle
down after a cold start, but I've always assumed that they were accurate -
even at idle. Maybe that is an incorrect assumption.
Sent:
Saturday, January 02, 2010 6:48 AM
Subject:
[FlyRotary] Re: first flight of the new
year
Happy New Year everybody!
Mike,
How far from the exhaust ports is your O2 sensor
located? Does anyone know what the minimum temp is for the O2
sensor? 800 degrees?
Bill B
From:
Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Saturday, January 02, 2010 8:31
AM
To: Rotary motors in
aircraft
Subject:
[FlyRotary] Re: first flight of the new year
Happy New Year to
you, Mike
Wow. I’ll bet
you are glad to be in a different year and glad the old one
gone.
I noted your
comment on the lean/rich possible O2 cause. Do you have a heated (3-4
wire) O2 sensor or an unheated one??
Ed
From:
Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills
Sent: Friday, January 01, 2010 9:43
PM
To: Rotary motors in
aircraft
Subject:
[FlyRotary] first flight of the new year
Hope the holidays are treating
you all well. Things are kind of slow on the list this week. So figured I'd
get things going.
I havent flown for almost 2
months. First my nephew's accident (he's recovering amazingly well). Then
travel for work. Then had to do an annual on the airplane. Finally, had
surgery to remove my appendix and gall bladder. Been a busy couple of
months.
But I'm feeling pretty good
now, the airplane is ready for its first flight after the annual, and today
was a spectacular day here with clear blue sky, unlimited visibility, light
breeze, and temps in the mid 60s. I resolved a number of minor issues during
the annual, including the gas smell that I've been living with for a
while now. Found my left tank vent line was loose where it penetrates the
bottom of the fuselage so was venting into the cockpit. The smell is now
completely gone.
Also found a solution to a
problem I've been noticing since I've started flying further from the
airport. I'd noted on previous flights when returning to the airport with a
long low power descent that the engine runs quite lean as I enter the
pattern requiring the mixture knob to be turned full rich. On a couple of
occasions I've had some misfiring as I turn final - quite an attention
getter! Today I realized the problem was a non-problem, in other words
operator error. While descending (and for that matter, frequently at other
times) I tweak the mixture based on the mixture monitor reading. Today I
ignored the monitor and just left the mixture alone which worked just fine.
I think during prolonged low power descents the O2 sensor cools
off and provides an inaccurate reading. The occasional misfire was the
result of running too rich (the mixture monitor indicated mid range
readings).
So todays flight was trouble
free and gets me an hour closer to the end of phase 1. 18 hours down, 22 to
go.
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