Sent: Sunday, July 20, 2003 3:09 PM
Subject: [FlyRotary] Tachs &
things
Hey
Guys;
I took the plane to the airport on Friday, mounted the wings and went
taxi testing yesterday. As simple as this may be for many of you, it was a bit
of a thrill for me. Everything seems to run great. I'm currently running the
EC2 in it's default settings as I was awaiting the EM2, before beginning
tuning, but as most of you are now aware it may not be available until
December. I bought a couple of temp & pressure gauges and a couple of
tachs. Today I'll go see if I can find an EGT & O2
sensor.
For those that are curious, The EWP seems to be working great, but with
one concern that I'll keep a close eye on. I taxied for about 20 min with one
full power run up, and temps never exceeded 85C, so the cooling system appears
to be adequate. Some of you may recall that I went with the Ford evaporator
cores because they fit in much better than the GM cores. Even though flow
tests showed that they had slightly higher flow rates than the GM cores, some
were concerned that they may not work due to a magazine article from
a few years back, where the two different cores were cut open for a comparison
of tube area, that showed the Ford cores appeared to be more restrictive. I
realize that it is still very preliminary, but so far I like what I see.
Now what concerns me.. I wired the EWP with a bypass switch so that I
can run the EWP at full speed, bypassing the temp controller. I also use this
switch to continue circulation after engine shut down. So yesterday after the
engine was shut down, I could hear the EWP pumping when suddenly it made a few
unhealthy sounding noises like it was about to seize, then it quickly returned
to normal and didn't do it again. I will keep a close eye on
this.
Now about tachs.. I've tried a couple of approaches. I bought a
Hastings tach, which I've currently connected to the EC2 tach output. Now this
is a 12 pulse/rev signal for a high resolution tach, like the EIS. So with the
tach set for an 8 cylinder 4 stroke, it should read 3X higher than
actual. My test runs show this to be right (I think), but once the tach wraps,
the needle will drop down to approximately 1/2, giving me a reading that is
closer to actual. This leads me to wonder if I can add a filter of some sort,
to get the right signal. Maybe a good question for 'electric Bob'. Tracy
suggested to Rusty that he could get a trigger signal from a coil trigger.
However this should produce 1/2 the actual signal, when set for a 4 cylinder.
So I theorized that a 2 stroke tach may produce an accurate signal so I
grabbed a Bombardier tach and wired it into a coil trigger, but like Rusty, I
found that this didn't work at all. I'm not certain why, as the coil trigger
should give at least some signal. My new ski-doo has a digital engine
management computer, which provides the tach signal, so I'm thinking that it
may be a high resolution signal, so I think maybe I'll pull it out and take up
to the airport and try it.
Is there anybody on this list that is using the EC2 and getting an
accurate signal to drive an inexpensive, off the shelf tach? What about those,
not using the EC2, how are you getting your trigger
signal?
Any input would be greatly appreciated.
S. Todd Bartrim
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm
"Whatever you vividly imagine, Ardently desire, Sincerely believe in,
Enthusiastically act upon, Must inevitably come to pass".