My Wooden Airplane
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12/13/2014 - 12/22/2014

Manifold Pressure

Even though I'm using a fixed-pitch prop, I've learned that manifold pressure is useful when trying to determine the effectiveness of that prop. In other words, I can't compare two fixed pitch props by looking at engine RPM and airspeed alone. Increasing the pitch by 1 inch and decreasing the diameter by 2 inches should result in roughly the same RPM at cruise. However, these changes would result in higher manifold pressure. If the manifold pressure increases but the airspeed remains the same, then I know I've reached the effective speed limit for this airframe, and further prop changes won't help.

Total Time: 3.0 hrs.