This is a 2" by 6" aluminium extrusion about 4 inches long. This is
very similar to what I am doing with the ignition stuff so I am all
set up to machine the covers.
There is an aux board the same size as the MM board mounted below the
M.
So far there are two VR sensor circuits and eight high current
drivers for four coils and four injectors on the aux board. The next
thing on the aux board will be two manifold pressure sensors. One for
he front rotor and one for the rear.
he back panel has the connectors for the VGA, the PC keyboard, the
USB connector and the 12 VOLT power connector.
The front panel will have two DB15's one for output and one for
input. Also a slot for the 65 gig SD card.
So far all through hole.
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Here is my latest iteration of the PC board. I added an RS232 9 pin
D-sub-min. Matt Boiteau is using that.
The surface mount manifold pressure sensors are on the right, 29 psi
so this board will work with turbo's. I am thinking of adding EGT
sensor circuits.
EGT sensors respond slowly so It mind be possible adjust the mixture
in cruise.
Of course they could be displayed on the EFIS part.
Anybody have any other things they would like added?
I should have this running on the RV4 in a few weeks.
Paul Lamar
I would want egt circuits.
I have a friend with an RV7 that is slightly tail heavy. I machined a
prop plate for him, 3/4 inch thick and weighs just under 14 lbs.
There is a bit more vibration with this plate so it needs to be
balanced. Anybody have any advice on balancing such a thing?
Also if anybody wants to see my machinery/capabilities please visit
my website:
www.cimmfg.us
Randy 113A Mill St. Silver Cliff CO 81252 Cimarron Mfg.
<
http://cimmfg.us/
Mount it on a shaft and roll it on parallel bars.Unfortunately if it
is not symmetrical around a centre plane it may be out of dynamic
balance. In that case you need a dynamic balancer.
BTW Randy my NC covers are on hold until I get a bit more money. I am
making a few on my cheap Chinese mill by hand with my poor man's DRO
:)
Paul Lamar Paul, a dynamic balancer is something else you could run
on a Maximite, especially if you have a crank position sensor. You
will need one more analog input, in this case for an accelerometer.
There are very cheap strain gage accelerometers available now with
preamp and signal conditioning. You need one of these bolted to the
engine block as close as possible to the prop hub. You will get a
waveform that you can calibrate in Gs or inches per second, and as
it's repetitive you can do a running average which can be then with
the crank sensor. The distance between 0 degrees at the crank and the
peak of acceleration shows you where the heavy blade or part of the
rotating machinery is. Dynamic balancers have come down a lot in
price in recent years but you could do this for a few dollars. If you
run an fft on the accelerometer waveform you can see all the other
rotating components. There are 3-axis accelerometer chips that are
also very cheap, you could plot the vibration in all directions.
David Josephson
Randy, you can normally find an A&P with a dynamic prop balancer at a
nearby airport. It usually costs about $300 to get the assembly balanced.
They will attach a sensor that reads the prop blades as they pass and reads
the acceleration in the x y z axes and calculated the approximate amount of
weight to add to the spinner bulkhead. Takes a couple of hours and requires
a few ground run ups. Easy. You will be surprised how much quieter the
airplane cockpit is after its done too.
Kevin Alderman
Kevin Alderman
A&P, GROL, ASEL
Comm/Inst
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