From idea to plans: a two-seat VTOL Geometry and flow view of a first propeller Propeller design point and off-design

Propeller: calculation, design and 3D modeling of propulsion and energy-capture propellers

Propeller calculation rests on a simple idea: each blade behaves like a rotating wing. For each slice of blade we calculate the relative and induced velocities, then the thrust, torque and efficiency of the propeller. This page presents the two families of propellers (propulsion and energy capture), the notion of pitch, and Heliciel's calculation methods and 3D modeling.

On this page:

The path of propeller calculation methods took a decisive step forward when the operation of blades was compared with that of rotating wings. Calculating the relative and induced velocities, due to rotation combined with the advance of the fluid, is essential to define the twist of propeller blades. Predicting power, lift or torque relies on practical theoretical tools, which you will find partly gathered here.

1: Propulsion propeller calculation: boats, aircraft and fans

Aircraft propellers, boat propellers and fans and ventilation are of the propulsion type. Their blades use the motor torque to accelerate the fluid and generate thrust by reaction (change of momentum). For details, see the page on aircraft, boat and fan propeller calculation.

Contra-rotating propulsion aircraft propeller with many blades around an engine nacelleFolding boat propeller with metal blades

Two propulsion propellers: a contra-rotating aircraft propeller and a folding boat propeller.

2: Energy-capture propeller calculation: wind turbines, tidal turbines and turbines

Capturing the energy of fluids uses propellers to turn the motion of the fluid into energy. The propeller then becomes a motor. Wind turbines, tidal turbines and axial turbines use the torque generated on their blades to drive generators, pumps or machines.

Rotor and nacelle of a wind turbine seen from below, against a blue skyTidal turbine submerged under a platform, cross-section diagram

Two energy-capture propellers: a wind turbine and a tidal turbine.

3: Propeller pitch: geometric pitch and effective pitch

Pitch is defined in several ways, and it is important to tell them apart. The page on geometric pitch and effective pitch explains them.

Diagram of an aircraft propeller in three successive positions, with the geometric pitch, the effective pitch and the slip

The geometric pitch, the effective pitch and the slip between them. (Figure labels in French: "Pas géométrique", "Pas effectif", "Glissement".)

4: Propeller calculation methods and 3D modeling

The propeller calculation methods predict performance, efficiency and the shape of blade profiles. Heliciel Heliciel logo, propeller and wind turbine calculation software is propeller calculation software for everyone: a simple knowledge of the basics of mechanics (force, torque, power, efficiency) is enough. It allows the calculation of propulsion propellers, the calculation of energy-capture propellers and the calculation of wings or hydrofoils.

Heliciel propeller performance calculation window: blade divided into elements in 3D view, thrust and torque charts per element

A calculation window of Heliciel: the blade is divided into elements, and the charts give the quantities of each element.

Heliciel uses airfoils whose performance and shapes are stored in a database to build a 3D propeller model. We can test the geometric shape of the blades, the number of blades and the rotation speed to evaluate thrust, torque and efficiency of the model. A plan of the blades and their profiles can then be edited.

To go further, we can see how twist and pitch angle are calculated along the blade, or how the history of calculation methods led to blade-element calculation.