Bill Greenwood wrote:
Randy, Say what? Those diagrams might be a little over my head!
This fighter pilot stuff isn't as low-tech-redneck as it once was, I'll give you that. Although the one I posted is a little tough to see, reading an EM diagram is pretty simple -- no more difficult that working a performance chart in the flight manual. More simple than that, in reality.
Very simply, this is a chart of
turn performance in a level turn at a specific altitude and weight. All you're looking at is a plot of airspeed on the "X" axis vs turn rate on the "Y" axis.
The reference lines sloping in from the top right show turn radius in feet. The lines sloping in from the top left show the "G" pulled in the aircraft.
The mountain shaped-line you see highlighted is the max performance of the aircraft. On the left hand side, the max lift limit line -- in other words, along that line you're on the edge of an accelerated stall. On the right side, is the structural limit (max G).
The lines in the middle that mimic the shape of the max-performance mountan tell you
how much energy it will cost you to turn that tight and pull that G.
This is what the real value of the chart is...to see what aircraft have the best turn rate/radius, AS WELL AS the thrust to support that turn.