A square tube propeller ship propeller

A ship propeller with a square tube propeller relates to a ship propeller, which includes an engine, a propeller and a square tube casing. The engine is mounted on the outside of the square tube casing through brackets. The rotation plane of the propeller is perpendicular to the output shaft of the engine, and the rotation plane of the propeller forms an acute angle with the opening direction of the square tubular shell. The section of the propeller is airfoil. The inner circumference of the cross-section of the square tubular shell is rectangular, the length of the rectangle is slightly greater than the maximum outer diameter of the propeller, and the width of the rectangle is slightly greater than the maximum external diameter of the propeller, the rotation plane of the propeller and the opening direction of the square tubular shell. The product of the sines of the acute angles formed. The propeller is completely inside the square tube housing. The propeller can rotate flexibly in the square tubular casing. Compared with the traditional ship propeller, the cross-sectional area of ​​the propeller of the present invention is much smaller when the flow rate is the same, and the efficiency is high and the resistance is small.