Abstract
In order to understand the flow passed through the controlable pitch propeller (CPP) blade and check the flow model used in theoretical analysis of its performances at off-design conditions, some attempts were made to observe the flow in the vicinity of moving model CPP in off-design condition particularly. One of them is the method that air is continuously injected into the fluid from trailing edges, and the other is solid particle tracer method. The particle which was adhered to the trailing edge of rotating blade was cut off at the same time as the shutter was released. It was found that the flow through CPP in the off-design condition is complicated, but the flow seems to form a part of helix line in the close rear of trailing edge at least.
