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kiloalpha · June 27th, 2009, 01:18

Out company for years and years have told us to run at 2300 rpms and 23" on the MP. Usually trues us out at 170-172kts and burns about 30-32 gph.

Now we are being told to run at 2200 rpms and 24" of MP. We are told this has no negative effect on the engine as is better for the props since they work more efficiently now. Is this true? Are we going pop cylinders and crack cases now? or is this actually going to work?

We have Lycoming IO-540s that make 290hp. Company research shows a fuel savings of 10% with a 1-2% drop in airspeed.

June 27th, 2009, 01:18	#1
kiloalpha Senior Member Join Date: May 2008 Location: . Posts: 520	Running props over square? Out company for years and years have told us to run at 2300 rpms and 23" on the MP. Usually trues us out at 170-172kts and burns about 30-32 gph. Now we are being told to run at 2200 rpms and 24" of MP. We are told this has no negative effect on the engine as is better for the props since they work more efficiently now. Is this true? Are we going pop cylinders and crack cases now? or is this actually going to work? We have Lycoming IO-540s that make 290hp. Company research shows a fuel savings of 10% with a 1-2% drop in airspeed. __________________