SR22 Cruise Power

Cruise power in a Normally Aspirated SR22 is simple, right? Just slect the bottom of the Rich of Peak (ROP) green band or the top of the Lean of Peak (LOP) band and enjoy. While mostly true, this is far from the best way to treat your engine for both performance and longevity. But, I want to keep it simple so that you don't need to be an engineer for Continental or Cirrus to enjoy flying your SR22.

Feel free to spend hours or days researching and watching videos on engine management, or, just use these techniques, which summarize my hours and days or doing the research.

Highlights:

• Lean of Peak for fuel efficiency, engine temps, and less strain on the engine.

• Maximum manifold pressure (MAP) at minimum RPM to blend power with quiet operation

• Mixture set 50 degrees lean of peak for maximum efficiency with lowest fuel burn

So, here' how we'll do this:

1. In climb, use wide open throttle and lean mixture every 1,000' or so to keep fuel flow at top of green band.

2. After leveling off, perform cruise checklist, switch tanks to fullest tank (if not in a G7) and open up the Engine Page on your MFD.

3. Pull power lever back to 2450-2470 RPM, then slowly increase power to maximum MAP before the RPM increases again. You are looking to push the power lever up to the point just prior to the Prop speed cam engaging and increasing RPM. You'll find that you get a large increase in MAP while RPM stays the same for a long while, then, you'll hear and see the RPM increase as the propeller speed cam is engaged. Ease back on the power lever at this time to go back to max MAP without the quick RPM rise.

4. Press the "Assist" soft key on the engine page and start to lean mixture slowly. Move slow enough for the EGT to register maximum EGT, but quick enought that you aren't spending a lot of time at peak EGT's. You want to minimize time above 1450 EGT.

5. Once EGT peaks, continue to lean until the last cylinder EGT is -50 from peak.

6. At this point - you have the most air coming into the engine (MAP) and optimal fuel/air ratio with EGT at 50 degrees lean of peak. This cruise power is best for quiet operation, engine performance and longevity.

7. If you change altitudes, you'll want to repeat this process as your MAP will change.

8. When starting descent, leave power lever where it is, but, watch your EGT's and when they start to climb, start increasing your mixture to the top of the green band and go full rich at 3,000' msl.

In Cruise, you should see RPM at 2480-2510, EGT's less than 1450 and CHT's less than 350, but normally in the 310-330 range. Fuel flow will be 3-4 GPH less than ROP and True Airspeed 5-10 knots less than ROP for great fuel savings with little speed sacrificed.