I got a great question this morning about the different types of cooling air passages in turbine blades, so here is my response.

This is the video that the question is about:    • AirCooled Blades  Turbine Engines: ...  

Also:    • Working on a Turbojet: 3 Turbine Coo...  

For more, go to my channel page and put cooling air in the search feature.