REFLECTOR: Cylinder Cooling

[John Dibble]

Don.  That's interesting.  I recently took egt data during leaning and found that both
the 5 & 6 cylinders peak last indicating they are richest.  Still trying to figure out
why.  My only theory so far is that when the fuel/air mixture in the manifold makes
the turn for each cylinder, the larger fuel droplets exit the stream due to
centrifugal force and end up at the #5&6.

John

Donald Royer wrote:

>
>
> On my Franklin, I have some evidence that #6 is probably the leanest
> running cylinder.
>
> Don
>
> > [Original Message]
> > From: Pat Shea <xl340hp at yahoo.com>
> > To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> > Date: 5/28/2007 12:19:54 PM
> > Subject: Re: REFLECTOR: Cylinder Cooling
> >
> > Chuck,
> >
> > With the o/h naca and plenum system, the #6 cylinder
> > tends to run hottest as it is closest to the firewall.
> > The consensus seems to be that the air coming down the
> > naca runner tends to flow over the #6 cylinder. The
> > same is normally true for the #5 cylinder but to a
> > lesser degree.
> >
> > I believe some have had success installing turning
> > vanes in the co-pilot naca to direct more air over the
> > #6 cylinder. On mine, I actually changed the shape of
> > the co-pilot runner during istallation by splitting it
> > down the side and then opening up (lowering) the end
> > that attaches near the engine. My #5 and #6 cylinders
> > tend to run about 20* warmer than the others. I
> > considered installing some 1/2" high Vg's in the
> > runners about 6" ahead of the #5 and #6 cylinders but
> > haven't tried that yet.
> >
> > With my angle valve IO-540, I have noticed a similar
> > increase is oil temps as you when increasing RPM from
> > say 2,400 to 2,500 RPM while maintaining a constant
> > power setting (24" X 2,400 or 23" X 2,500).
> >
> > Pat
> >
> >
> >
> > -- Chuck Jensen <cjensen at dts9000.com> wrote:
> >
> > > Hiroo,
> > >
> > > My #6 runs the hottest on my IO540 but I always
> > > attributed that to the
> > > oil cooler tapping off NACA air right in front of
> > > it.  I have the
> > > pressure box on top of the engine with CHT in the
> > > 340F-360F common and
> > > #6 about 400F.
> >
> >
> >
> >
> >
> >
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