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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