Schilling Rudder
Encyclopedia
A Schilling Rudder is a specific type of profiled rudder used on certain boats and ships. See Rudder
One of the effect of a Schilling rudder is to deflect the flow of water generated by the propeller, to assist in turning, and when the rudder is at angles of 90 dgerees or more to the direction of the propeller generated thrust, this can direct the thrust forward and provide a significant braking effect on the ship.
A twin rudder configeration can significantly contribute to such an effect, and when used in conjunction with bow thruster, even quite large ships can be can be given considerably enhanced maneuverability.
Other slow moving boats, or boats with slower moving propellers, are also very suitable to the fitting of a Schilling Rudder.
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 principle proportions of a Schilling rudder layout are as follows:
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.
Rudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...
The Schilling Concept
The Schilling Profile is designed to improve the effective lift generated by the rudder and hence improve the maneuverability of the craft, especially at slow speeds. The rudder is effective in both forward and reverse.Use of the Schilling Rudder
Due to the nature of the design, the Schilling Rudders are commonly fitted to large slow moving ships such as container ships and oil tankers. Particularly as also longer/narrower ships are more prone to lack maneuverability due to their inherent shape.One of the effect of a Schilling rudder is to deflect the flow of water generated by the propeller, to assist in turning, and when the rudder is at angles of 90 dgerees or more to the direction of the propeller generated thrust, this can direct the thrust forward and provide a significant braking effect on the ship.
A twin rudder configeration can significantly contribute to such an effect, and when used in conjunction with bow thruster, even quite large ships can be can be given considerably enhanced maneuverability.
Other slow moving boats, or boats with slower moving propellers, are also very suitable to the fitting of a Schilling Rudder.
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 principle 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.