Research Article
Design Method for Contra-Rotating Propellers for High-Speed Crafts: Revising the Original Lerbs Theory in a Modern Perspective
Table 3
Main characteristics of CR propellers used for the parametric investigation.
| ā | Case A-l | Case A-2 | Case A-3 |
| Front number of blades
| 4 | 4 | 4 | Aft number of blades
| 4 | 4 | 4 | Front EAR | 0.82
| 0.87 | 0.79 | Aft EAR | 0.94 | 0.98 | 0.89 | Strength margin | 5 | 6 | 5 | Cavitation margin fore | 0.78 | 0.78 | 0.83 | Cavitation margin Aft | 0.7 | 0.7 | 0.75 | Unloading curve | Y | Y | Y | Propeller efficiency | 0.704 | 0.699 | 0.71 |
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