The effects of power are considered in two 
main categories. First, there are the direct 
effects resulting from the forces created by the 
propulsion unit. Next, there are the indirect 
effects of the slipstream and other associated 
flow which alter the forces and moments of the 
aerodynamic surfaces. The direct effects of 
power are illustrated in figure 4.11. The ver- 
tical location of the thrust line defines one of 
the direct contributions to stability. If the 
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