FORCE EQUATIONS IN WIND AXES

The force equation of motion is (5.4,9). In wind axes it becomes

iw = macw

with &Cw given by (5.3,11). For the particular case of a stationary atmosphere

(5.3,15) gives the acceleration components, so that the scalar equations of motion are

fxw =

fvw = mV{rEw + rw) (5.5,1)

Szw = -™V(qEw + qw)

Although all the terms of (5.5,1) may be needed for applications to hypervelocity flight, there are numerous exceptions in which the Earth rotation can be neglected. The result is then much simpler, viz.

fxw =

fvw = m^rw (5-5,2)

fzw = – mVqw

Not only is (5.5,2) simpler in form than (5.5,1), but the angular velocities rw and qw that appear in it are those of Fw relative to Earth and not to inertial space, and are themselves correspondingly simpler.

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