Page 21: of Maritime Reporter Magazine (October 2016)
Marine Design Annual
Figure 2: Scan Converter can be used to extract the design parameters and recreate the blade.
ers, allowing them to quickly identify the inspection points on the blade and provide a proper comparison for the de- sign thickness and local pitch values.
PropCad includes four inspection maps for determining inspection point location and inspection values for thickness and local pitch. These maps produce a tem- plate of the developed blade outline, which can often be directly laid on top of constant pitch propellers to approxi- mate the inspection point position. The inspection maps that are now featured in
PropCad Premium are: • Thickness map – provides the local thickness values of the blade at each in- spection point. The maximum thickness is also identi? ed and labeled separately.
• Local pitch map – provides the mea- sured value of local pitch for a segment of the blade surface at each inspection point. speci? ed Y and Z ordinate from the shaft senting the axial height of the blade at placement blades typically requires ge- • XYZ location map – provides the axis. a speci? ed radius (R) and angle (Theta) ometry different from the ? nal design as coordinates of the inspection points in • X-R-Theta location map – provides from the shaft axis. part of the foundry process. Building a a Cartesian coordinate system. Each the coordinates of the inspection points propeller by sand-casting, for example, inspection point has an X value repre- in a cylindrical coordinate system. Each Castings and Patterns requires three critical geometries: senting the axial height of the blade at a inspection point has an X value repre- Manufacturing a new propeller or re- • The ? nal design shape (of course).
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