Eric you are spot on.
In 2010 I put the TLR46 TCU on my old Rotax 914 and I didn't see the airbox temp
on my thermocouple go above 140 C so that told me I didn't need any intercooler
as we did on the Jason Parker modified 914. His engine had a simple vacuum
dashpot turbo control, so the boost came on later as RPM increased).
Personally, I use full turbo for takeoff to check it works as advertised, more
than actually needing the power for takeoff. My inlet temp was measured by a
thermocouple clamped to the plenum for my tests originally. (I don't have a
probe
in the engine although there is a port.) I was more concerned about heat
during the extended climb at max continuous and my CHTs and found TOT was not
a factor with the new TCU in 90 F degree summer heat.
In the Parker engines I would put a bag of ice on the intercooler and found that
could make a huge difference but in fact we needed a larger intercooler, the
width of the engine, to be effective without ice on the slower planes. The flow
of air in these small turbos is not that great and the mass of the cooler
was more important as a temperature dissipater on hot California desert days
than
the inlet and discharge. That is just my opinion down here in hot Florida.
We every day fliers don't race the other fast glass planes like in the very
early 2000's at Sun n Fun to fool with the turbo. We want to fly safe and
efficiently,
or we wouldn't own the Europa. (They told me the Eclipse would win
because they wired open the wastegate to get the factory Europa mono's by a
couple
knots.)
In general: Use good gas, go to full turbo for takeoff and pull it back when
safely
airborne and leave it in max continuous for the climb is all most Europa
owners need to do. Where the TCU places the turbo wastegate is information not
needed to fly or worry about the old TCU temperature anti knock waste gate
limiter but its nice to know and that is what data logging is good for. The
charts
in the book are good enough for a reference. I would recommend , just prior
to annual, wash the bird, bring your laptop along and hook it up on the D
sub you put in the cockpit for your TLR 46 recording. Go fly: Record the data
at start for a few seconds, then hit L to stop log, then hit L again and record
takeoff, transition to climb and then hit L to stop, then L again to turn on
log for passing 5000MSL, and go into cruise at 5500 MSL (East Coast and 7500
Western mountains may be better) and let the engine stabilize at cruise, trim
it up, and enjoy the flight. At cruise, record into your camera or on paper,
the trim, rig, your desired aircraft upgrades, deficiencies, malfunctions,
analyze
your stall and slow flight for feel, stall recognition and reaction then
land and take the data home. Break it down, prepare your inspection checklist,
gather parts, and then go to the hangar/workshop/garage and take care of mx
business.
The stock 914 installation per the manual is adequate with some attention to the
ducting. Because the power output (BTUs) are higher on the 914, watch your
cylinder temps with the new engine on extended climbs. Climb at 90-100 Kts will
help on break-in of a new engine. Set your plane up for good recording. Dynon,
Grand Rapids, and of course the famous Rotax recording methods are good
things to build into your plane and assist you in flight testing as you will
find
data recording to be time consuming and distracting. Let the computers do
their thing and you fly the airplane, clear for traffic, concentrate on good
airmanship in flight, the pattern and landing.
Just my opinion,
Bud Yerly
Custom Flight
-----Original Message-----
From: owner-europa-list-server@matronics.com
<owner-europa-list-server@matronics.com>
On Behalf Of Erich Trombley
Sent: Wednesday, July 05, 2023 11:18 AM
Subject: Europa-List: Re: Rotax 914 Dyno Test
Hello all,
Having flown my Europa Monowheel, powered by an early 914 for over 20 years, I
find this discussion interesting. I initially installed my engine with an
intercooler,
however after a few years I removed it, rationalizing that it was
unnecessary since 100% power is all that I ever use for takeoff, and I cruise
at 75% power. I figured it was just extra weight and so out it came.
Unfortunately,
at the time I was not monitoring airbox temp as my engine monitor wasnt
that sophisticated.
That changed when I installed my Dynon Skyview with a very capable engine
monitor.
I found that the airbox temperature was as high as 170 F which exceeded
the intervention temperature (160 F) for my early motor. So, I reinstalled the
intercooler which knocked the airbox temp down to 132 F max.
Considering the new TCU has an intervention temperature of 190 F, the
installation
of an intercooler may not be necessary. YMMV.
Lastly, regarding the DO 178 B takeoff. I believe the english translation of
the
operating manual my be incorrect. The description of the DO 178 B takeoff
is correct, stating that the takeoff is performed with a deactivated servo motor
of the TCU. This makes sense considering Rotax requires a double pole, single
throw switch be installed to isolate the servo motor should the engine be
unable to maintain a steady RPM at high power settings. However, the steps
listed
to perform the DO 178 B instruct you to turn off the TCU. I believe this
is an error, as doing so would cause the TCU to perform a self test upon being
turned back on, which would cycle the waste-gate, something you would not want
to happen while in flight. Rather, I believe the manual intended to say that
you should deactivate (isolate) the servo motor with the above reference switch
while keeping the TCU on. In this manner, when the servo motor is turned
back on, the TCU will not recycle the waste-!
gate, but will adjust the waste-gate as necessary based on the current throttle
position.
Looking forward to seeing everyone at OSH later this month,
Erich
N28ET Classic Mono 914
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