Efficiency of a propeller is defined as the ratio of available power to the engine power which is. . (3). Note, that this definition for efficiency contains the velocity v, which means, that the efficiency approaches zero as the flight speed goes to zero, because the thrust cannot become infinitely large. So this definition is not useful for the special case of static thrust.
1 Compound Fracture: A compound fracture is a fracture in which the injured bone sticks through the skin. 2  Also known as an open fracture, a compound fracture can be a bit more serious in nature.
There are many types of fractures, but the main categories are complete, incomplete, compound and simple. Complete and incomplete fractures refer to the way the bone breaks. In a complete fracture, the bone snaps into two or more parts; in an incomplete fracture, the bone cracks but does not break all the way through.