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Old 01-14-2018, 03:04 PM
spatsch spatsch is offline
Join Date: Nov 2014
Location: Randolph, NJ
Posts: 191
Default 2018 IAC Sportsman and your engine

I frequently get the question:

"Do you need an inverted system to fly the IAC Sportsman routine in a contest?"

As others have stated before you don't. However, I figured people might like to see some data to back this up.

Below shows the oil and fuel pressure during the 2018 IAC Sportsman routine with an IO-360 a fixed pitch prop and NO inverted fuel or oil pickup (I do have an inverted system on the breather line as I got tired of the amount of oil in my hangar...).

Min oil pressure during the routine is above 45psi at all times and min fuel pressure is 7.8psi. I had about 5qt of oil in the engine. The engine never stumbled. Please note that the longest period of low oil pressure is during the Hammerhead turn (around 13:20) and an inverted system wouldn't help there at all as you are at 0g (so the oil would be neither on the bottom nor top pickup and gravity driven valves don't properly seat at 0g).

Lycoming has max oil pressure at 95 psi and min between 25-55 depending on RPM. (See:

Hope that helps.

Oliver Spatscheck
RV-8 & J-3
N-2EQ & NC-49762
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