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发表于 2007-5-10 13:19
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来自： 英国
回复: 有关舵的问题
没有找到贝克舵，但我猜是不是Kitchen rudder？有知道的朋友请告诉一下。
另外，从http://en.wikipedia.org/wiki/Rudder找到了舵的分类，如下：
Conventional ship and boat rudders
Specialist ship and boat rudders
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Schilling Rudder
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A Schilling Rudder is a specific type of profiled rudder used on certain boats and ships. See Rudder
The Schilling ConceptThe Schilling Profile is designed improve the affectness of the rudder and manoeuvrability ability of the craft, especially at slow speeds. And is effective in both forwards and reverse.
Use of the Schilling RudderDue 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 manoeuvrability due to there inherent shape.
Other slow moving boats, or boats with slower moving larger propellers, are also very suitable to the fitting of a Schilling Rudder.
The Schilling ShapeThere is little concrete information available regarding the exact shape of the Schilling Rudder. However, the basic shape is a relatively simple ‘fish shape’ if viewed from above. And as well as the profiled sections, a pair of flat plates top and bottom to prevent or minimise end-effect on the aerofoil.
As can bee seen from this image.
 
Depiction of Schilling Profile
A CAD model of a Schilling Rudder
A Schilling Rudder fitted to a small steam powered launch.
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 2/5 of the length leading flat section lasting for around 1/5 of a cord-length, finalising 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 at 2xMaxWidth.
The height should be similar to the diameter of the propeller, with the chord length being upto 1.2 times the propeller dia. If extreme manoeuvrability is not required, chord length can be reduced to a minimum of 0.55 x Propeller diameter.
Around 40% balance should be provided (plate infront 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 at 2*70 Degrees.
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Kitchen rudder
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Kitchen Rudder. Image from the 1916 U.S. patent.
Enhanced design to the Kitchen Rudder. Image from the 1990 U.S. patent.
KLM Fokker 70 with reverse thrust applied. The two surfaces behind the engine can be seen in the deployed position, diverting the engine exhaust gases (hence thrust) forward. This is similar to the Kitchen rudder in "Full astern" position
The Kitchen Rudder is the familiar name for "Kitchen's Patent Reversing Rudders", a combination rudder and directional propulsion delivery system for relatively slow speed displacement boats which was invented in the early 20th century by Admiral Jack Kitchen of the British Royal Navy. It turns the rudder into a directional thruster, and allows the engine to maintain constant revolutions and direction of drive shaft rotation while altering thrust by use of a control which directs thrust forward or aft. Only the rudder pivots; the propeller itself is on a fixed shaft and does not.
"Kitchener gear" or "Kitchener rudder" have been common misnomers for the Kitchen rudder.
It is held under British Patent 3249/1914 and US Patent 1186210 (1916) and has been improved with the design in US Patent 4895093 (1990)
DescriptionThe rudder consists of a pair of slightly conical (usually but not always - designs vary), semi-cones mounted on a pivot either side of the propeller with the long axis of the cone running fore and aft when the helm is midships. They are pivoted about a vertical axis such that the cone may close off the propeller thrust aft of the propeller, directing the thrust forwards and thus creating motion astern.
In addition to the "jaws" of the cone being controlled the direction of thrust is also controlled by rudder direction (compare this with an outdrive or an outboard motor for direction of thrust of an unenclosed propeller where the propeller itself pivots).
Modern equivalent include certain types of pump jets or the jet drive.
While not strictly Kitchen rudder technology, the "clamshell" reverse thruster on some aircraft jet engines is an aeronautical derivative of the device. The picture of the aircraft shows the clamshells deployed directing thrust forwards. This is equivalent to the Kitchen rudder in the "full astern" position.
Operation
NeutralThe engine is brought up to speed with the drive to the propeller engaged and with the Kitchen rudder in the "neutral" position. This is a position where an equal quantity of thrust is aimed forward and aft. Each vessel will have a unique "neutral" position
Moving aheadThe Kitchen gear is opened up to direct an increasing proportion of thrust aft. As the balance changes the vessel will move ahead.
Moving asternThe Kitchen gear is closed to direct an increasing proportion of thrust forward. As the balance changes the vessel will move astern |
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