The geometry of the propeller

Design: propeller, turbine, screw, aerial, marine, turbine, tidal, wind, kaplan, foil, wings, 3D. Discover heliciel software:

The propeller geometry

Understand and master the propellers geometry:

Here we will define the geometry and vocabulary to describe a propeller

propeller geometry

he X axis represents the axis of rotation or the propeller shaft.The direction and speed of the upstream fluid is parallel to the X axis
The y-axis Represented the axis of the blade. For variable pitch propellers is the pitch change axis.
P represents the plane of rotation of the propeller. The disc swept by the blades of the propeller, is located on the plane of rotation.
W is the angular velocity of rotation. This speed can be given in radians / second (rad / sec) or revolutions per minute (Rpm or rev / min)

The propeller blade is described by profiles, which divide it into elements:

Bootup screen software propellers and wings design HELICIEL

The elements of the blades are framed by profiles located at a distance R on the axis of blades:

propeller geometry

To optimize the efficiency of the propeller blade profiles are usually aerodynamic or hydrodynamic shape. (Detailed profiles blades Description).

propeller profile

The profile chord line connecting the leading edge to the trailing edge
L = chord length
A= leading edge(attack) of the profile
B= trailing edge of the profile
e= Maximum thickness profile
d= distance leading edge and blade axis

The pitch of the propeller deserves a detailed description because it is necessary to distinguish the geometric pitch of the propeller, and the effective pich of the propeller:The combination of the rotational speed and the speed of the fluid generates a speed composed, which we will call Apparent speed.The angle between the fluid path and the plane of rotation is the apparent angle.

propeller attack angle incidence spedd

The angle between the apparent direction of the fluid and the profile chord is the angle of incidence or attack angle:

le calage des profils de la pale est réglé por que l'angle apparent et la corde donne une incidence optimum

The profiles can be arranged along the blade axis in a line which is called the generator profiles. this Generator profiles can be curved in the direction of rotation. This curvature generator is called "skew". The generator may also form an angle with the plane of rotation. This gives conicity angle to the propeller. This angle moves the blade tip back in the plane of rotation. This offset is called "Rake" .

interface generator in HELICIEL

The curvature of the generatrix of the blade, coupled with twisting, causes a shift of the profiles to the rear. It therefore generates a conicity induced by the curvature of blade generator. This even if no cone angle is given to the generator.