REFLECTOR: Exhaust systems

Scott Derrick reflector@tvbf.org
Tue, 15 Jul 2003 16:47:20 -0600


Now that is interesting!  Now I see how they are getting 220 HP..

I'd figure a bit more than that considering I can get 210 in my Lyc with 
10.5 to 1 pistons at 2700 RPM. Maybe its not as efficient as advertised?


Scott

Jim Agnew wrote:
> Careful Brian that 220 HP is at 3200 RPM and the data plate
> says 205HP at 2800 RPM so it is close to the lycoming 200
> IO-360 given the tuned intakes & FI with a lower
> compression ratio.
> 
> Jim
> --- Brian Michalk <michalk@awpi.com> wrote:
> 
>>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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> 
> 
> 
> =====
> James F. Agnew
> Jim_Agnew_2@Yahoo.Com
> Tampa, FL
> Velocity 173 Elite Aircraft Completed
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