tommayer wrote:

Paul,
    I had one more probably useless idea on the prop.
    It might behoove you guys to see what props they ran on Monocoupes. Monocoupes were equipped with a variety of slow turning radials and fixed pitch wood props.  I have an airline capt buddy, a Monocoupe owner and expert,  who assures me a Monocoupe with a 165 or 185 Warner radial will easily true 200 mph in cruise and get off like a Super Cub, all with an engine redlined at 2200 rpm, normal aspiration, and fixed pitch wood prop.  Maybe a search of the Monocoupe, Lambert and  Warner type certificates, or a chat with somebody knowledgeable at Sensenich,  would tell you just what you need to know.
    I've flown Great Lakes with 180 Lycs and C/S Hartzells and one with a fixed pitch wood prop on a 185 Warner. The slow turning old Warner would pull that airframe in circles around the Lyc C/S specimens, although of course all of them were slow.
    For sure 150-185 hp airplanes, bigger and probably heavier than RV-4s, were getting RV performance with fixed pitch props at lower rpms than you are talking about 65 years ago.  Tom Mayer

Those big old large diameter slow turning props were very efficient indeed.

Paul Lamar
 
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