Steering classification.geometrical characteristics of the rudders .
The rudders are classified according to the following features: the location of the axis of the puller according to the width (chord) of the rudder; -the method of mounting the steering wheel; the shape of the steering profile On the first sign distinguish unbalanced, semi-balance. cilpille il balancing steering wheels . The balancing part is called the part of the rudder area, located in front of the axis of the baller. The presence of the balance part makes it possible to reduce the hydrodynamic moment relative to the axis of the baler and, thus, the power of the steering gear. If the balance part is not available over the entire height of the steering wheel, then it is accepted to call such a steering wheel half-moon. lansirnym. The second sign determines the place and method of fastening the steering wheel . So, the unbalanced steering wheel can be located behind the rulerpost or deudood, the semi-balancer – behind the deadwood on the bracket, the balancing steering wheel can be suspended (when the steering wheel is attached only to a puller). also have an additional support on the heel of the stern-bow. According to the shape of the rudder profile, they are flat (straight ° yr0l. in cross-section) and streamlined! n (profiled). The most widely used are profiled rudders, which, at a sufficiently high strength, have high hydrodynamic quality in the real range of angles of lining interact well with the propeller propeller. The rudders do not install newly built vessels and both. the scope of their use is not limited to self-propelled vessels
On the whole, the rudder elements of the corpus design on which it is fixed are characterized by a number of dimensional and relative geometric characteristics, the main of which are the following: the area of the rudder Sp; area balance Noah part of Ss: the area pv. Dorpasta smi square crown matte urenla3x, the area of the complex steering wheel – rudder post steering wheel – bracket. Spini you honeycomb feather steering h; bracket height hr: width (chord) of the rudder feather bp, if the steering feather has a non-rectangular shape, then the concept of average width is introduced, bp – Sp / h; bmi rulerpost width bracket width br: snrin complex steering wheel – bpip rudder post. – Sp- + pn / h; width of the complex steering wheel – _ bracket bp1K – Sph / h; the relative elongation of the rudder feather is 112 / Sp. relative elongation of the rudder – rudder post 2.p p, -112 / Sp + pn, relative elongation of the rudder – bracket complex steering wheel: profile. TsAGI (Central Aerohydrodynamic Institute named after N. Ye. Zhukovsky); -the theoretical profile of HEK (N. E. Zhukovsky); USA), the NASA profile (Aeronautics and Space Administration, the Go profile (Gettnite Laboratory) listed ellille npot | With conventional wings, the cross-sectional profile, along with its high hydrodynamic quality, should bake sufficient strength. From this point of view, NASA profiles are preferable to re-use the metric profile characteristics most The maximum profile thickness.tmax is the relative thickness of the profile-: ((max / b). 100% focus on the choice of the main geometric characteristics – the area of relative elongation 2, 11 of the steering wheel of the compensation factor ensure the desired controllability depends on the size of the
The height of the helm feather hp depends on the height of the feed gap, and thus the width Lp and the relative length, sepa Hul for a given area Sp are determined practically by design. Greater rudder efficiency corresponds to the augmentation extension of which for maritime transport vessels is within 1.4-2.6. The rudder compensation coefficient of modern ships is recommended to be equal to k – 0.18 0.24. The compensation compensation factor takes into account that the estimated pexmor of the vessel is forward. A forward-looking ka bullet on the forward run of Mb.nx must be at least sro. At the back of the vessel, MB, 21, to fulfill this condition, it is sometimes necessary to restrict the head of the rudder on the vessel and the speed of the vessel when maneuvering from the rear xsd . The number of rudders is determined by the designation of the ship by its structural features. The efficiency of the rudder is ignored when it is installed directly behind the rpecan wto .. Therefore, for cargo and passenger ships, the number of rudder is equal to the number of screws. It should be noted that increasing the raft is possible only by increasing its width. However, the latter leads to a decrease with respect to yznzena and, accordingly, to a decrease in the efficiency of the rudder. In such a case, it is advisable to install two rudders with A, instead of leaving the optimal range.