Paul, and the group
A lot has been written about aftermarket computers for our aero
conversions. However, is there any reason why the stock engine computer
can not be used? Does anyone have any experience in using stock? Good or
bad? How does one go about configuring the stock unit for aircraft use?
Engine is a 13b single turbo with fuel injection.
Thanks and regards,
--
Erik Snyman
Messina
South Africa.
Perry Mick has over 500 hours with the stock computer. There are a
few tricks
however. The stock computer takes in some data from certain places that
don't exist in an airplane. I'll let Perry explain it if he doesn't
mind.
As I recall the big hang up is leaning it. Perry was working on a
solution
for that as I recall.
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BTW HKS makes a bunch of add on device that change the output of the
varies
RX8 engine sensors in real time. I suspect they are basically
PICAXEs with
analog to digital converters that take in the sensor voltage and
covert it to a
different analog output voltage to be fed into the stock OEM computer.
I think this is the way they did it with this 390 HP turbo RX8 engine.
http://www.rotaryeng.net/Turbo-RX8a.jpg
For example if you wanted to lean the OEM computer for use at
high altitude you would take in the mass air flow sensor output voltage
and change it so the the stock OEM computer thought it was getting less
air than it actually was. Consequently it would put out less fuel.
Pretty easy to do with a $30 PICAXE.
Paul Lamar ...No rotor no motor.
Paul,
I would have reservations about using an OEM computer at high
altitudes. (Or any computer that has not been proven for aircraft
use, for that matter.)
The reason is that as atmospheric pressure drops, it becomes easier
for electrical current to jump gaps and end up where it's not
supposed to. We see this in aircraft magnetos that have arc-over at
higher altitudes. That's why some of the turbocharged planes have
pressurized magnetos.
It is anyone's guess how the electronics inside an engine computer
will behave at pressure of even half that at sea level (15,000 feet
approx.). They may work fine, they may not.
My own opinion is that I would rather not fly a stock engine
computer above 10 to 12 thousand feet. At this altitude the stock
computer should be able to handle the leaning anyway.
For any serious flying above that, my preference is for a purely
mechanical ignition system (flywheel magneto, a la Rotax), and carb
or mechanical fuel injection.
Regards,
Gordon.
Those are real high voltages Gordon. Not a problem at 5 volts. Sparks are
20,000 volts and up.
Most engine computers have a coating over the parts called a conformal
coating which acts as an insulator. At Pikes peak in Colorado there
is a road to the top at 14,000 feet as I recall where the
public can and do drive to the top. Perry has had no trouble with this in
over 500 hours.
Paul Lamar ...No rotor no motor.
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