REFLECTOR: Ideas for cooling the #6 (far out) cylinder.

[Michael Watson]

Hiroo,

Is your plenum one piece that covers the entire top of the engine as
supplied by the factory for the Franklin ?  If yes, you may want to
do what others including myself have done to greatly reduce CHT temps.

Cut out the center section of the plenum and fabricate down sides with
flanges that attach to the threads left and right of the engine top cover.
The result, two separate plenums tightly secured over each cylinder bank.

Before I made the change, I could not climb more than 400 FPM and had to
level off at 3000 ft cool down for a while then continue the climb. After
the
conversion, I can now climb straight to any altitude in the Florida heat
without
exceeding 392 F. Oil temps usually settles at 190 ~210 during climb and 185
during cruise.


On 6/3/07, Hiroo Umeno <humeno at microsoft.com> wrote:
>
>  I had another flight where the scope of the flight was limited by the #6
> CHT and the oil temp.  I think the oil temp can be addressed by adding an
> exit baffle the sucks the air out of duct more forcefully.
>
>
>
> The CHT is a puzzling one.  I got a few suggestions for adding a baffle
> under the cowl to direct more are to the #6 that is really way out there at
> the end.  The trouble is, I am having a hard time figuring where and how big
> the baffle should go.  Does anyone have any suggestions?
>
>
>
> It was a 80 degree day in Seattle and I had to keep the plane at 3000ft,
> 110Kts, power pulled fairly far back so that the #6 CHT and the oil temp
> won't redline.
>
>
>
> On a related topic, I knew that if I got higher where the air is cooler,
> and went faster where I got more airflow, I could keep things cooler.  The
> trouble is, I couldn't get there without redlining something.  Would it be
> bad to fly it Redlined on one cyl for a few minutes it takes to get high and
> fast enough?  I've been trying really hard not to keep things in red for
> long for fear of doing some damage to the engine.
>
>
>
> Hiroo
>
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-- 
Mike W
1997 Velocity Elite RG
Franklin /IVO Electric CS
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