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MattH150197
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Homework Statement
In a lab experiment we ran the simulation of 3 different flight conditions into a program that produced graphs of the oscillations in them conditions and we have to do a comparison of the SPO (short period oscillations) characteristics for the 3 flight conditions which are the following with FlightCondition 1 being the first value ,FC2 the 2nd and of course FC3 the 3rd:
: velocity = 177, 177, 177 Pitch Inertia = 7.6x 10^5, 7.6x10^5, 7.6x10^5 Change in pitching moment due to change in pitch rate = -4.2x10^5, 0, 5x10^5 Change in pitching moment due to change in normal speed = -9.11x10^4, -9.11x10^4, -9.11x10^4 then the last is the velocity * change in pitching moment due to a change in rate of change of normal speed = -3.12x10^5, 0, 3.7x10^5.
The graph produced for FC1 was a damped/stable oscillation, FC2 was undamped/ critically stable and FC3 was unstable /divergent oscillation. But I am struggling to get my head around why change in pitching moment due to change in pitch rate and velocity * change in pitching moment due to a change in rate of change of normal speed (these two in particular because the rest were the same for each condition) had the effect they did on the SPO? Thanks hope what I am asking makes sense.