Great to hear good
flight reports, Mike. That's the pudding of the
effort.
I found that
(apparently due to ) more air flow in the induction system during flight than
on the ground that air/fuel ratios tend to apparently lean out a bit. In
any case, whatever the cause, I found it necessary for a bit more richness for
smooth reliable low rpm operation in flight than on the ground. Also,
increasing your idle rpm a bit could help – it's not a welcome feeling to have
the engine run anything other than smooth especially when near the
ground.
Thanks for the Plug
on the EFISM. I agree that the use of a graphical display of the fuel
map is much easier for most folks to see peaks and valleys in their fuel
map. So either Tracy's EM2/3 or (shameless plug – learned
that phrase from someone {:>)) the EFISM can truly assist in smoothing it
out and getting a smoother running engine. The manifold bins are around ½" –
¾" "wide" and each of the 128 bins should receive individual attention –
however, I personally found it very difficult to keep the engine
stabilized in a pressure bin while I tried to tune it. Making it richer
or leaner would most of the time change the manifold pressure as engine
operation changed slightly – besides trying to tell ½" manifold pressure on my
gauge was nearly impossible.
There's no question
you can get the engine tuned well enough to fly safely without such fine
tuning – but, not really optimum.
I'd like to keep
hearing your flight reports, Mike. Flight
safe.
Ed
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Mike Wills
Sent: Sunday, February 15, 2009 11:52
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Second
flight
Spent the last month addressing
issues uncovered during my first flight. Today was the day for flight number
2. OAT was in the low 50s. Temps during climbout up to 6,000 were good.
Leveled out and stayed at full throttle for a couple of minutes just to see
what happens. Saw indicated airspeed in the mid 150KTS range. RPM was 5500.
Both were still creeping up when I throttled back. Looks like I may be
slightly over-propped. Temps still fine.
Throttled back to 5000 RPM
and just flew racetracks over the airport for an hour. My flight test area is
very restrictive. I've got a huge piece of the desert to the east but have to
cross a 3500' mountain and 30 - 40 miles of rugged terrain to get there. Not
until I have a few more hours on it in flight and have 100% confidence. I have
the Mexican border 2 miles south, Class B 2 miles north and the Pacific Ocean 5 miles west. So racetracks over the
airport are going to be the norm for a few
hours.
So, 5,000', 5,000 RPM,
roughly 20 - 21" MAP, and indicating 140 KTS. Temps 170 on the coolant and 168
on the oil. I've already met my goal for this airplane on the second
flight - this airplane is a little faster than my old RV-6A was at equal power
settings. The -6A had a 160 HP Lyc in it.
Looks like the revised
static system has solved my airspeed indication problems. Stall speeds are in
line with the Vans book numbers and airspeed correlates pretty well with the
GPS groundspeed. Still need more left trim
tab.
The engine ran great. Anyone
trying to tune up Tracy's EC2 without either having an EM2/3 or
Ed Anderson's EFISM, you're wasting your time. I spent the better part of a
year tweaking the MAP table and thought I had it pretty well done. On my first
flight I spent a fair amount of time fiddling with mixtures and had a couple
of rough running spots. I installed Ed's EFISM and spent 2 days tweaking. In
the process I got the engine running smoother than it ever has and now have it
idling nicely at 1350 RPM. Thats 300 RPM lower than I was ever able to get it
previously. In my opinion you really HAVE to have some sort of indication
of what is loaded in the MAP table to effectively tune
it.
The only hiccup was when I
came in to land. Tower asked for me to extend my downwind for traffic so I
added a little power to hold altitude. And ended up setting the power right at
the injector staging point, which still seems to run a little lean. Nothing
like having the engine cough just as the runway is receding over your left
shoulder. Took me a couple of seconds to realize what was going on and then
added a little power and that cleared it
up.
Then managed to bounce the
landing. How many landings can I log on one approach? Oh well, I guess I'm a
little tailwheel rusty. And without the cowl cheeks the view over the nose is
very different so I havent quite got the pitch attitude figured out
yet.
Other impressions. The
airplane is loud, but not painfully so. At least not from the pilot's seat.
The handling and control power still seem quite a bit better than my RV-6A
(which was great). Not really clear why but most of my flying in the -6A I had
someone in the right seat so maybe the weight? Other than the rudder, the
airplane flies perfectly straight.
All things considered I'm
real happy. This flight was considerably less stressful than the first and I
actually was able to enjoy it. I honestly dont remember a lot of the first
flight. Also, I took my glider data logger with me on this flight. I havent
downloaded it yet, but when I do I'll know more about speeds, climb rate,
etc.
Dont know how you guys feel
about these flight reports. Give me some feedback if you want more as my
testing progresses. I know that I like reading about other's flight
experiences as it motivated me to keep going. After 13 years of building I'll
tell you, its worth it. Now I wish I'd pressed harder to get it done
sooner.
Next flight will have to
wait until I get gear leg stiffeners added. Classic RV - pretty bad shimmy on
the roll out after landing. 38.5 hours to
go!
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