Schilling Rudder - The Schilling Shape

The Schilling Shape

There is little reliable information available in the public domain regarding the exact shape of the Schilling rudder. However, the basic shape is a relatively simple ‘fish shape’ if viewed from above as seen in the figure to the right. And as well as the profiled sections, a pair of flat plates are typically fitted top and bottom to prevent or minimize end-effect on the aerofoil.

The basic principal proportions of a Schilling rudder layout are as follows:

• Max Width of aerofoil at 20% chord.
• Taper to 60% chord.
• Flat to 80% Chord
• Flare to 100%

Or in other words, a bulbous widening for 1/5 of the total length of the rudder blade, with a streamlined narrowing for 2/5 of the length leading to a flat section lasting for around 1/5 of a cord-length, finalizing in a blunt-ended flared trailing edge for the remaining fifth.

The width of the trailing edge to be 33% of the max width of the profiles. Width of plates to be around twice the maximum width of the rudder.

The height should be similar to the diameter of the propeller, with the chord length being up to 1.2 times the propeller diameter. If extreme maneuverability is not required, chord length can be reduced to a minimum of 0.55 x Propeller diameter.

Around 40% balance should be provided (plate in front of the rudder pivot)

The distance from the trailing edge of the propeller to the leading of the rudder should be a minimum of 0.2xPropellor diameter. And the maximum angle of operation is 2*70 degrees.