Hi Ferg
Figured would mention that for those operating a 914, you should be familiar
with
a RTCA DO 178 B take off as depicted in the 914 operators manual.
To make things simple, the complex sensor riddled 914 has those sensors
connected
to the TCU (Turbo Control Unit). The TCUs only decision making it is capiable
of is to leave the wastegate opened, or close it.
If you are counting on war emergency power (115%) to clear that 150 foot tree at
the end of your 800 foot runway in the middle of the summer that is situated
on the peak of a mountain, it would be a real drag if your TCU for one of many
reasons descided to turn your Belsh fire 914 into a 912. If you turn off TCU
with wastgate closed and use your throttle to limit boost to maximum, you can
be assured wastegate will at least remain closed. This would not be a good idea
for long periods of time, but to clear hazard, a good thing to know about.
Another attribute to knowing your power plant, is you can cycle things and shut
off servo with wastegate full opened. This way if you have some sort of
malfunction,
just turn it into a 912.
Just a side note, if you overboost a 914 because for whatever reason the
wastegate
is remaining closed, the fuel pressure regulator can not keep up with demands
of motor and you will run out of gas in carb float bowls, when enough gas
fills bowls engine will come back to life, and run out again, etc. etc. anyway
if you were able to turn off turbo by opening wastegate, motor is just a 912
and chances are things will be fine till you get on ground. If you had a
differential
fuel pressure gauge you could see the tail wagging the dog. If you use
throttle to limit MP, for a short time not too bad a thing, but you can
overspeed
turbo and make it work plenty hard with the restricted outpu, not too good
for long life of turbo.
Anyway if you fly a 914, be very familiar how to reboot or cycle TCU and
practice
to learn what is normal, and if all else fails practice how to just plain turn
it off. Also if you are depending on more than what your motor can put out
as a 912 to clear an obstruction, practice DO 178 b take offs.
Ron Parigoris
Visit - www.EuropaOwners.org
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