Propeller Selection Principles

     There are so many variables that affect the performance of a particular class of airplanes yet the common practice is to choose the propeller based upon engine displacement alone.  As we have shown, the propeller is only one part of an interactive system that includes the engine and airframe.  And the properties of the air in which you are flying also have a significant influence on all three of these components.  With all this in mind, Vess Propellers were designed to allow fine tuning of an aircraft for peak performance. 

     Information presented on the tech info page described the design philos-

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ophy of these props and introduced the size designations.  Here, we will further define the proper principles for selecting the right Vess Propeller so that you can enjoy the full performance of your aircraft.

Step 1 - Choose a Diameter

     The one thing that is conventional about these props is the designation of the diameter.  It is described by the two-digit number printed on the side of the prop hub and has units of inches.  In general, the choice of a diameter will put you into a “class” of engine and airframe.  For example, our 32 inch diameter prop series was optimized for typical 150cc-powered aerobatic aircraft.  Of course, there are many different engine and airplane combinations that could utilize this same series, so the choice of diameter also serves as another tuning variable.  But, in general, the diameters that are currently chosen for different aerobatic setups are a good place to start here.

Step 2 - Choose a Pitch Series

    As discussed on the tech info page, the pitch is not defined by a constant helical value in inches as with conventional props, but by an alphabetic letter.  This is because the optimized pitch distribution for each prop is not constant or linear and, thus, cannot be described by a single value.  In actuality, the A-B-C pitch series concept provides an intuitive means of tuning the prop load.  This process is driven by the simple understanding that the “B” series is intended to be the normal or baseline load and the “A” and “C” produce less and more load, respectively.  You could probably utilize the “B” prop and note increased performance compared to your normal prop.  But there are added performance and noise benefits to be gained from further adjustment.  The follow graphic describes some of the reasons why you might change from the baseline pitch series.


Step 3 - Adjust as Required

    As we have repeated many times, one objective of this prop sizing concept is to allow for the adjustment of performance to not only meet differences in aircraft and engines, but also to keep pace with weather changes.  This fine level of adjustability is quite useful and powerful!

      Even when you use the selection methods described here, you may find that you cannot meet your needs within a specific diameter series.  In that case, you must move to a smaller or larger diameter as the situation dictates.  The line of Vess Propellers is ever-expanding and will eventually include enough sizes to meet virtually any requirement.  Stay tuned to this site for constant updates.

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