Chapter 6: stability and control
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Then:
The trim diagram for this aircraft will look like Figure 6.10, so: 
and: 
The aircraft will be in equilibrium when it is at its equilibrium (trim) angle of attack and at a true airspeed such that lift equals weight, so: 
If the aircraft were launched at 15 ft/s, it would still trim at e and the corresponding CL so: 
So, if launched at  = 15 ft/s, the aircraft would commence a pull-up into a loop at load factor 4.2. Unless it had sufficient thrust, its speed (and the load factor) would begin to decrease as its flight path angle increased until the aircraft either completed the loop or pitched back down at a lower speed and load factor. Eventually, after perhaps several oscillations of airspeed and flight path angle, it would stabilize at its trim airspeed, 7.3 ft/s. As long as the air density and the aircraft geometry and weight are as described, it can only be in equilibrium when flying in level flight if it is at its trim airspeed.
In addition to the airspeed/flight path angle oscillation just described, the aircraft would also experience an angle of attack oscillation as described by Figures 6.5 and 6.9. The airspeed/flight path angle oscillation is called the aircraft’s Directory: ~jps7 -> Aircraft%20Design%20Resources Aircraft%20Design%20Resources -> Systems in Transportation: The case of the Airline Industry Download 2.68 Mb. Share with your friends:
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