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Wooden vs Metal Fixed Pitch vs Constant Speed Propellers by Martin Sutter   
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I have a 180 HP RV6 that I have been flying for 1650 hrs.  For all but the last 100 hrs it flew with a fixed pitch prop.  First 1300 hrs with a Sensenich wood prop, next 250 hrs with a Sensenich metal prop (Sensenich did a lot of the testing of that prop on my airplane) and the last 100 hrs with a Hartzell constant  speed.  

Here is how it stacks up:  
The wood prop was very smooth with with good take off performance, good cruise climb and a 2700 rpm cruise of 190 mph.  At full throttle it would over rev by 200 rpm so it was probably under-pitched.  I liked it a lot but the main draw-back is it's not suited to flying in the rain.  

The metal prop was much to my surprise even smoother than the wood prop (I had all props statically and dynamically balanced).   Take off was more sluggish but cruise climb was very good and 2700 rpm cruise yielded 200mph.

The constant speed unleashes a surprising amount of additional performance on take-off.  Cruise climb is about the same as with the metal prop and full throttle cruise at 8000' and 2600 rpm is 210mph (speed is greater at 2600 rpm than at 2700, indicating this prop is not fully optimized for this application).  The biggest advantage is that you can cruise at 190mph turning 2300 rpm and a slightly better fuel economy.  The other benefit is that it makes the airplane a much better short field performer both on take off and landing due to the much greater braking action of the prop in fine pitch. The C/S prop does not run as smooth as the fixed pitch props, particularly at high manifold pressure and low rpm.  

The short of it - for the money the Sensenich metal prop is the best value.  For the budget get wood.  If money is no hindrance go for the constant speed.

Martin Sutter