CDA HVG 77 Series User Manual download pdf (Page 27)

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vlm.doc Surfaces – User Manual – Vortex-Lattice Module Page 27 of 82

Figure 17: Trim progress is displayed on the ‘Progress Plot’ tab.

When the analysis completes you will see the results as shown in Figure 19. Without going into too many

details, we can see from values for Cma (-2.119), Clb (-0.105), and Cnb (0.172) that our airplane is

statically stable about all three axes. What we don’t know at this time are its dynamic stability properties.

And this is what we intend to investigate next. First, however, we must transfer these results to the

airplane model.

STEP 23: Select the ‘Transfer’ tab. Follow the remaining steps closely.

STEP 24: Press the [Select All] button to select all the derivatives in the

list.

STEP 25: Press the [Deselect Nonrequested] button to deselect the derivatives

that were not calculated.

STEP 26: Uncheck the following variables: CL, CD, Cda, hcg, and hn (see

Figure 20). This will prevent them from being overwritten, but they already

consist of algebraic expressions that we don’t want to be deleted.

STEP 27: Press the [Transfer] button. Press the [OK] button on the

notification form that pops up stating a successful transfer. Then press the

[Close] button to close the Stability Derivatives form.

Now we proceed to the dynamic stability analysis.

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CDA HVG 77 Series User Manual Page 27