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.
Compound Fractures. Many people have heard the term compound fracture. But what does it mean and why is it such a serious injury? The term compound fracture is an older medical term that describes the fracture of a bone that then has contact with the outside environment through a break in the skin. The term used today by orthopedic surgeons is an âopen fracture.â