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Date: Tue, 21 Aug 2012 13:56:44 -0500
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Subject: Re: [FlyRotary] 20B OMP question
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Thomas,

After initially running pre-mix in my 3-rotor Lancair ES, I recently
installed the 20B OMP.  I use a see-through container mounted on the
firewall which holds approx. 8 hrs. worth of 2-stroke oil.  This required
one of Richard Sohn's OMP adapters.  As the 20B OMP utilizes a computer
controlled stepper motor to control oil flow, and I don't have a clue as to
how to properly control it in my application, I built a block-off plate
with an adjustment screw to replace the stepper motor.  There is a plunger
under where the stepper motor is located that controls the amount of oil
the OMP injects, and it is very sensitive.  But with a bit of trial and
error you can get the mixture right on 1 oz./gallon of fuel burn.  It works
great and I no longer pre-mix.

BTW, I stopped pre-mixing when I realized that the oil was not getting
evenly mixed in my fuel tanks due to the numerous baffles inside the tanks.
 The only passages through the baffles are some small "mouse holes".  I
attribute unevenly mixed 2-stroke oil to some excessive wear on one of my
rotor housings.  This wasn't a problem initially as I was using auto gas
and hauling it in a fuel trailer.  The 2-stroke got mixed well during the
drive to the airport.  I had to switch to 100LL when the gov't. began
mandating 10% ethanol in all auto fuels.  (the ethanol was incompatible
with the adhesives in my wing tanks).  Adding the 2-stroke during
re-fueling was inadequate to get a good even mix of 2-stroke/100LL
resulting in engine damage.  At least that's my best guess.

Also, unlike the pre-mix method, the OMP keeps pumping oil even when the
throttle is fully closed.  So, if you pre-mix, be careful of running for
too long with the throttle closed like if you are high and need to make a
steep descent.  I think the OMP is a better system.

Mark S.

On Tue, Aug 21, 2012 at 1:27 PM, Thomas Mann <thomasmann51@gmail.com> wrote:

> I'm looking at using a small tank of 2-cycle oil as a source for the oil
> injection system on my 20B.
>
> I have a single point fueling system the splits up my fuel and diverts it
> to two wing tanks. I am concerned that pre-mixing may cause me problems
> when it comes to ensuring that the proper mix/ratio is evenly distributed,
> hence the OMP.
>
> I am told that the footprint on the stock OMP is the same as the Electric
> 13B pump.
>
> Has anyone successfully implemeted such a system and if so, could you
> share the particulars?
>
> Thanks.
>
> T Mann
>

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Thomas,=A0<div><br></div><div>After initially running pre-mix in my 3-rotor=
 Lancair ES, I recently installed the 20B OMP. =A0I use a see-through conta=
iner mounted on the firewall which holds approx. 8 hrs. worth of 2-stroke o=
il. =A0This required one of Richard Sohn&#39;s OMP adapters. =A0As the 20B =
OMP utilizes a computer controlled stepper motor to control oil flow, and I=
 don&#39;t have a clue as to how to properly control it in my application, =
I built a block-off plate with an adjustment screw to replace the stepper m=
otor. =A0There is a plunger under where the stepper motor is located that c=
ontrols the amount of oil the OMP injects, and it is very sensitive. =A0But=
 with a bit of trial and error you can get the mixture right on 1 oz./gallo=
n of fuel burn. =A0It works great and I no longer pre-mix. =A0</div>
<div><br></div><div>BTW, I stopped pre-mixing when I realized that the oil =
was not getting evenly mixed in my fuel tanks due to the numerous baffles i=
nside the tanks. =A0The only passages through the baffles are some small &q=
uot;mouse holes&quot;. =A0I attribute unevenly mixed 2-stroke oil to some e=
xcessive wear on one of my rotor housings. =A0This wasn&#39;t a problem ini=
tially as I was using auto gas and hauling it in a fuel trailer. =A0The 2-s=
troke got mixed well during the drive to the airport. =A0I had to switch to=
 100LL when the gov&#39;t. began mandating 10% ethanol in all auto fuels. =
=A0(the ethanol was incompatible with the adhesives in my wing tanks). =A0A=
dding the 2-stroke during re-fueling was inadequate to get a good even mix =
of 2-stroke/100LL resulting in engine damage. =A0At least that&#39;s my bes=
t guess. =A0</div>
<div><br></div><div>Also, unlike the pre-mix method, the OMP keeps pumping =
oil even when the throttle is fully closed. =A0So, if you pre-mix, be caref=
ul of running for too long with the throttle closed like if you are high an=
d need to make a steep descent. =A0I think the OMP is a better system.</div=
>
<div><br></div><div>Mark S.<br><br><div class=3D"gmail_quote">On Tue, Aug 2=
1, 2012 at 1:27 PM, Thomas Mann <span dir=3D"ltr">&lt;<a href=3D"mailto:tho=
masmann51@gmail.com" target=3D"_blank">thomasmann51@gmail.com</a>&gt;</span=
> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex"><div>I&#39;m looking at using a small tank o=
f 2-cycle oil as a source for the oil injection system on my 20B. </div><di=
v>
=A0</div><div>I have a single point fueling system the splits up my fuel an=
d diverts it to two wing tanks. I am concerned that pre-mixing may cause me=
 problems when it comes to ensuring that the proper mix/ratio is evenly dis=
tributed, hence the OMP.</div>

<div>=A0</div><div>I am told that the footprint on the stock OMP is the sam=
e as the Electric 13B pump. </div><div>=A0</div><div>Has anyone successfull=
y implemeted such a system and if so, could you share the particulars?</div=
>

<div>=A0</div><div>Thanks.</div><div>=A0</div><div>T Mann</div>
</blockquote></div><br></div>

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