REFLECTOR: Exhaust systems

Brian Michalk reflector@tvbf.org
Tue, 15 Jul 2003 11:58:25 -0500


Franklin engines are 10.5:1 compression ratio with 350 cubic inches, and are
rated at 220 horsepower, normally aspirated.  Compare this to a Lycoming
0-360 rated at 180 horsepower.  More heat(energy) goes into the work.
The second thing that could cause low EGT is the very high valve overlap.
There is a lot of scavenging going on in a Franklin cylinder, causing
volumetric efficiencies of 103% at the cruise RPMS.

> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of Scott Derrick
> Sent: Tuesday, July 15, 2003 11:09 AM
> To: reflector@tvbf.org
> Subject: Re: REFLECTOR: Exhaust systems
>
>
> This sounds very odd.  I think av gas in a near optimal
> mixture(Stociometric?) burns at 1500+ F. It doesn't matter whether its
> in your Honda Civic, your lawn mower or aircraft engine.
>
> Maybe its the placement of the EGT probe.  The absolute temp is really
> of not much concern because where you stick the probe in and how the
> exhaust flows in the pipe will effect the probe temperature quite bit.
> Its the trend that is of prime importance.
>
> Scott
>
> John Dibble wrote:
> > I just spoke with an A/P that works on Franklin engines.  He
> says I should not expect
> > my EGT to exceed 1000 F.  Franklin engines run cooler.
> >
> > John
> >
> > steve korney wrote:
> >
> >
> >>John...
> >>
> >>In that case your running way to rich...You should see temps of
> about 1250
> >>to 1300 (f) on take-off...
> >>Maybe that's the reason it stumbles so much on run-up...Lean it
> out...Keep
> >>the temps above 1150 on the ground or you won't vaporize the lead in the
> >>fuel and it will foul your plugs...
> >>
> >>Best... Steve
> >>
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