Investigation of Transonic Drag Computations in Aerodynamic ...

Investigation of Transonic Drag Computations in APAS
With the method by which APAS creates the transonic drag rise determined as the
addition of wave drag above Mach 1, the next step was to check whether or not wave
drag could be reduced by “coke-bottling” one of the trial configurations. Analysis of the
original six configurations would then be repeated in another program, with the hopes of
achieving results with which those from APAS could be measured and compared.
4.1.7 APAS “Coke-bottle” Geometry Results
The geometry of Trial 3 was modified by reducing the cross-sectional area of the
fuselage in the region of the wing root as seen in Figure 28255 below.
100 ft.
R 5 ft.
20 ft.
R 4.5 ft.
40.6 ft.
Figure 28. Trial 3b APAS Geometry
This modification results in a “coke-bottle” geometry that has been proven to
reduce wave drag. The APAS results, when compared with those of the normal Trial 3
configuration, demonstrate that this method of reducing wave drag works in APAS. The
“coke-bottle” geometry was analyzed only in APAS, in order to prove the validity of this
method in the reduction of wave drag. The resulting area buildup can be found in
Appendix B.
Jeff Miller 24