Finn Lassen wrote:

This morning I saw some numbers that didn't make much sense to me:

5500 RPM, WOT at 5000'
Fuel flow: 15 GPH
Airspeed: 180 mph (two way GPS)
Oxygen sensor: 820mV (slightly rich)
EGT about 1600F (I'm seeing as much as 1760F when I pull throttle back
and mixture leans and oxygen sensor drops to less than 500mV)

The prop is obviously overpitched, but even guessing at a SFC of .6 can
the 13B produce 150 HP at 5,500 RPM?

Does anybody have a formula, table or curve of oxygen sensor readings
versus fuel consumption (SFC)?

Finn

Tracy Crook wrote:

150 HP is not unreasonable depending on how clean or dirty the plane is but
I would guess that the HP is slightly less but the mixture is way rich.  EGT
at max power should be about what you saw at lower power,  1760 F.

I think there are too many variables to come up with a generic chart for O2
readings versus fuel consumption.  The main point you should probably work
on is the over rich condition at WOT.

Tracy Crook
rws@altavista.net
www.rotaryaviation.com

 
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