Calculateur de Pas et Glissement d'Hélice ⚙️
Calculez le pourcentage de glissement et le risque de cavitation. Entrez le pas, diamètre, RPM et rapport.
Comment utiliser le calculateur d'hélice
Entrez le pas (pouces), diamètre, RPM moteur, rapport de transmission et vitesse GPS réelle.
5–15% de glissement est normal. Plus de 25% indique une coque encrassée ou une hélice endommagée.
Le risque de cavitation est basé sur la vitesse en bout de pale (π×D×RPM arbre/12). Moins de 9 000 ft/min est sûr.
FAQ
What is propeller slip and how is it calculated?
Propeller slip is the difference between theoretical speed (pitch × RPM / gear ratio / 1215.2) and actual GPS speed. Slip % = (theoretical − actual) / theoretical × 100. Normal recreational boats run 5–15% slip.
What causes high propeller slip?
High slip (> 25%) is caused by hull fouling, propeller damage, incorrect pitch for load, or heavy displacement. Clean hull regularly, inspect prop blades for nicks, and consider re-pitching.
What is cavitation and how does tip speed affect it?
Cavitation occurs when propeller tip speed creates low-pressure bubbles that implode on the blade surface, causing damage and loss of thrust. Tip speed = π × diameter × shaft RPM / 12. Below 9,000 ft/min is safe; above 14,000 ft/min is critical.
What is the ideal propeller slip for recreational boats?
5–15% slip is ideal for most recreational planing boats. Displacement hulls typically run 10–20%. Racing props can achieve 3–8%. Slip outside these ranges warrants inspection.