REFLECTOR: N173VS RPM

[Geoff Gerhardt]

Andy,

Thanks for all the good suggestions.  I'm typically only able to get out to
the hangar on weekends, but its supposed to be in the 50's here this week,
so I'll probably sneak out there a couple evenings this week to check on a
few of the things you've mentioned.

While I have the great Dynon Skyview system that tracks all the engine
parameters, I'm kicking myself now for not taking note of more
temperatures/pressures.  I was so excited to be taxiing around, I was
looking outside to be sure I didn't hit something more than looking at the
panel.  Even when I was just standing still doing the static runup, I was
listening to the engine and adjusting the mixture and things and not paying
enough attention to all the sensor readings other than making sure the oil
temp/press was coming up.  I will probably connect my laptop to the skyview
for the next start and log everything so I can look back on it.

Anyway, there's a number of issues that I need to resolve before I try
again.

   - I need to figure out why my fuel pressure reading is so low.  I
   checked the sensor, and it responds to pressure changes, is getting fuel
   and has good grounding.   Oil pressure sensor mounted beside it works fine
   (indicating good ground to the block their both mounted on).  My feeling is
   that the low pressure is real, but I'm going to connect an analog dial
   gauge and check it.
   - There's still a problem with my LightSpeed EI.  The disable switch
   does not work.  Only when I turn power off to the EI unit does it stop
   working.  Also, the RPM output from the LightSpeed unit is not
   working/being seen by the Dynon Skyview.  I have it connected to the
   low-voltage Tach input of the Dynon EMS, but when I switch off the Mag, RPM
   drops to zero when only running on EI (the Dynon allows two RPM inputs and
   should switch intelligently b/w them).  The EI unit seems to be functioning
   well and providing good spark aside from these issues, tho.

Once I resolve these issues, I'll give it another go...

One other thing - when I go to full throttle, the engine starts to sputter
and I need to lean it out (~ half way) to achieve maximum power.  Is that
consistent with a fuel flow problem?

Thanks again for the help.

Geoff

On Tue, Feb 21, 2012 at 9:57 AM, Andy Millin <amillin at sbcglobal.net> wrote:

> Geoff,****
>
> ** **
>
> Congrats on the taxi.  It looked great.****
>
> ** **
>
> If you are looking for some help on the low static RPM…****
>
> ** **
>
> You said you were getting low fuel pressure readings.  What fuel flow do
> you get?****
>
> ** **
>
> It looks like you have a Lightspeed EI.  Are you running 1 and 1?  What is
> the “mag” check like.  Are both systems firing.****
>
> ** **
>
> Do you have an engine monitor?  What are the EGTs and CHTs looking like
> when running on either ignition system.****
>
> ** **
>
> How much time have you spent on leaning the engine.  When I started my
> engine on the plane, it was running very rich.  The Catto prop is very
> light and will not be much of a flywheel.  So, you’re keeping the RPM up
> just to keep it running.****
>
> ** **
>
> I have a Prince prop.  It was a challenge to get it to idle below 800
> RPM.  It wasn’t until Terry Brokaw helped me get the idle settings right
> that I could get it to 600 RPM.****
>
> ** **
>
> Where is your fuel pressure sensor located?****
>
> ** **
>
> If you are running both the mechanical and electric fuel pumps, there is a
> pretty good chance you can make the pressure you need.  The pressure to the
> spider will be controlled by the Servo.****
>
> ** **
>
> If the EGTs and CHTs are in the same ball park for all cylinders, then the
> blockage (if any) would be before the spider.  Fuel Filter, Fuel Shutoff
> Valve, lines, etc. ****
>
> ** **
>
> It is also possible your prop is over pitched.  Craig has been known to do
> that.****
>
> ** **
>
> Andy****
>
> ** **
>
> ==========================****
>
> Andy Millin****
>
> amillin at sbcglobal.net****
>
> ** **
>
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