PSModel a look inside

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Introduction

Quick Start

Quick Series
Facts

PSModel
Program

Data Input

Data Output

Importing a
Data file into
MS Excel

Main Menu

Main Screen

Printing
Graphs
and Data

Screen Colors
and Fonts

Screen
Graphs

Shortcuts

Working
with Data

Testing:

Test Sheet

Examples

19' Ski Boat

34' Sailboat

41' Utility Boat

Technical

Blade Area
Ratio

Calculating
the Cavitation
Number

Horsepower
Losses

Hull Speed

Kt Breakdown

Propeller
Geometry

Propeller Law

Wake Factors

Glossary

References

Propeller Geometry:

(B) -- B Series blade form and sections drawing for EAR = 0.70 and 4 blades.  Note the 15 degrees of blade Rake and small amount of blade Skew

B Series propeler geometry

(GBD), (GBA), (GBL), (GRJ), and (GBR) -- Gawn Burrill Series blade form and sections drawing for DAR = 0.80 and 3 blades.

Gawn-Burrill propeller geometry

(NV3) -- Navy 3 Bladed Series geometry details.  Note the skew or sweepback of the propeller blades and flat faced blade sections typical of many commercial propellers used on small craft.

Navy 3 Blade Series propeller geometry

This following describes the Cup geometry used for NV3.

1) Maximum Cupping is at the 0.70 radius of the propeller blade (the radius is measured from the center of the propeller hub).

2) Cupping trails to 0 at the blade tip and at the 0.4 radius.

3) The maximum angle that the Cupped blade face makes with the flat blade face is 30 degrees, see the diagram below.

4) The table and diagram below show the Cupping geometry used for testing:

R -- nominal radius of the propellers tested = 12 inches

0.7R -- 70% of propeller radius, measured from the center of the hub

tmax -- average of the maximum blade thickness, for 3 blades, at 0.7R

X -- average of the blade trailing edge drop due to Cupping, for 3 blades, at 0.7R, see diagram

Rc -- estimated Cup Radius

Chord -- average length of the uncupped blade section nose tail-line, for 3 blades, at 0.7R

Nominal
 P/D
Cup
Name
X
@ 0.7R
(Inches)
tmax
@ 0.7R
X/tmax
@0.7R
Chord
(Inches)
Cup
Radius, Rc
(Inches)
1.0 Light 0.2396 0.421 0.569 10.49 1.8
1.0 Medium 0.3854 0.437 0.882 10.16 2.9
1.0 Heavy 0.6458 0.428 1.509 10.09 4.8
1.24 Light 0.1875 0.511 0.367 10.28 1.4
1.5 Light 0.1979 0.544 0.364 10.37 1.5
1.5 Medium 0.3542 0.526 0.673 9.98 2.6
1.5 Heavy 0.5313 0.515 1.032 9.89 4.0

Cup detail drawing

5) The Navy 3 Bladed Series roughly follows the Recommended Cupping Guidelines presented in reference 3.  Another approach for standardizing Cupping can be found in reference 11.

(NV4) -- Navy 4 Bladed Series geometry details.  Note the skew or sweep back of the propeller blades and the flat face blade sections typical of many commercial propellers used on small craft.

Navy 4 Blade Series propeller geometry

(NR) -- Newton Rader Series geometry details.  Note the unique blade section designs intended to function under fully cavitating conditions.

Newton-Rader propeller geometry