1      SUBROUTINE VTAREA(VTIN,AVT,VERTUP,XV,ZV)
2C
3C *** EXECUTIVE TO COMPUTE VERTICAL TAIL AREA SHADOWED BY MACH LINES
4C
5      COMMON /OVERLY/ NLOG,NMACH,I,NALPHA,IG
6      COMMON /WINGD/  A(195)
7      COMMON /HTDATA/ AHT(195)
8      COMMON /WINGI/  WINGIN(100)
9      COMMON /HTI/    HTIN(154)
10      COMMON /CONSNT/ PI,DEG,UNUSED,RAD
11      COMMON /FLGTCD/ FLC(73)
12      COMMON /SYNTSS/ SYNA(19)
13      COMMON /FLOLOG/ FLTC,OPTI,BO,WGPL,WGSC,SYNT,HTPL,HTSC,VTPL,VTSC
14      LOGICAL EFFECT,VERTUP
15      LOGICAL HTAIL,FLIP,ANGCHG
16      DIMENSION XP(5),YP(5),XX(4),YY(4),AA(3),XI(4),YI(4),SVWB(2),
17     1          SVHB(2),AREA(2),X(5),Y(5)
18      LOGICAL FLTC,OPTI,BO,WGPL,WGSC,SYNT,HTPL,HTSC,VTPL,VTSC
19      DIMENSION VTIN(154),AVT(195)
20      DATA STRA/4HSTRA/
21C
22      HTAIL=.FALSE.
23      ANGCHG=.FALSE.
24      NCON=0
25      SVWB(1)=0.
26      SVWB(2)=0.
27      SVHB(1)=0.
28      SVHB(2)=0.
29C
30C     COORDINATES OF INBOARD VT PANEL
31C
32 1000 XP(1)=XV+(VTIN(4)-VTIN(3))*AVT(62)
33      YP(1)=VTIN(4)-VTIN(3)+ZV
34      IF(.NOT.VERTUP) YP(1)=VTIN(4)-VTIN(3)-ZV
35      XP(2)=XV+AVT(21)*AVT(62)
36      YP(2)=AVT(21)
37      XP(3)=XP(2)+VTIN(5)
38      YP(3)=AVT(21)
39      XP(4)=XP(1)+AVT(10)
40      YP(4)=YP(1)
41      XP(5)=XP(1)
42      YP(5)=YP(1)
43      XMACH=FLC(I+2)
44C
45C     TEST FOR VT POSITION
46C
47      IF(VERTUP) GO TO 1020
48      DO 1010 N=1,5
49 1010 YP(N)=-YP(N)
50      XMACH=-XMACH
51 1020 AMUU=ATAN(1./SQRT(XMACH**2-1.))
52C
53C     CALCULATE LE AND TE MACH LINE INTERSECTIONS WITH VT PANEL
54C
55      DO 1220 J=1,2
56         FLIP=.FALSE.
57         IF(HTAIL) GO TO 1030
58         AA(1)=SYNA(2)+(WINGIN(4)-WINGIN(3))*A(62)*COS(SYNA(4)/RAD)
59         AA(2)=SYNA(3)-(AA(1)-SYNA(2))*SIN(SYNA(4)/RAD)/
60     1         COS(SYNA(4)/RAD)
61         AA(3)=SYNA(4)
62         IF(J.EQ.1) GO TO 1050
63         AA(1)=AA(1)+A(10)*COS(SYNA(4)/RAD)
64         AA(2)=AA(2)-A(10)*SIN(SYNA(4)/RAD)
65         GO TO 1050
66 1030    IF(SYNA(4).EQ.SYNA(8).OR.ANGCHG) GO TO 1040
67C
68C     CALCULATE XH AND ZH FOR HT WITH INCIDINCE ANGLE EQUAL TO THAT OF
69C     WING  (ROTATION ABOUT 1/4 MAC)
70C
71         HACLE=(HTIN(4)-HTIN(3))*AHT(62)+AHT(30)-AHT(16)/4.
72         XHAC=SYNA(6)+HACLE*COS(SYNA(8)/RAD)
73         ZHAC=SYNA(7)-HACLE*SIN(SYNA(8)/RAD)
74         SYNA(6)=XHAC-HACLE*COS(SYNA(4)/RAD)
75         SYNA(7)=ZHAC+HACLE*SIN(SYNA(4)/RAD)
76         ANGCHG=.TRUE.
77 1040    AA(1)=SYNA(6)+(HTIN(4)-HTIN(3))*AHT(62)*COS(SYNA(4)/RAD)
78         AA(2)=SYNA(7)-(AA(1)-SYNA(6))*SIN(SYNA(4)/RAD)/
79     1         COS(SYNA(4)/RAD)
80         AA(3)=SYNA(4)
81         IF(J.EQ.1) GO TO 1050
82         AA(1)=AA(1)+AHT(10)*COS(SYNA(4)/RAD)
83         AA(2)=AA(2)-AHT(10)*SIN(SYNA(4)/RAD)
84 1050    CALL PTINT1(XP,YP,AA,AMUU,X,Y,XI,YI,NSUM,EFFECT,KK,J,NCON
85     1              ,VERTUP)
86C
87C     CHECK FOR MACH LINE NOT INTERSECTING VT
88C
89         IF(J.NE.1) GO TO 1060
90         IF(EFFECT) GO TO 1070
91         GO TO 1230
92 1060    IF(EFFECT) GO TO 1070
93         AREA(J)=0.
94         IF(KK.EQ.1) AREA(J)=AVT(1+NCON)-AREA(J)
95         GO TO 1200
96 1070    IF(NSUM.NE.0) GO TO 1080
97         AREA(J)=0.
98         IF(J.NE.1) FLIP=.TRUE.
99         GO TO 1180
100 1080    CONTINUE
101         GO TO (1090,1100,1110,1120,1130,1150,1160) NSUM
102 1090    CONTINUE
103 1100    CONTINUE
104C
105C     HERE FOR MACH LINE INTERSECTING LE AND TIP CHORD
106C
107 1110    XX(1)=XI(1)
108         XX(2)=X(2)
109         XX(3)=XI(2)
110         YY(1)=YI(1)
111         YY(2)=Y(2)
112         YY(3)=YI(2)
113         GO TO 1170
114C
115C     HERE FOR MACH LINE INTERSECTING LE AND TE
116C
117 1120    XX(1)=XI(1)
118         XX(2)=X(2)
119         XX(3)=X(3)
120         XX(4)=XI(3)
121         YY(1)=YI(1)
122         YY(2)=Y(2)
123         YY(3)=Y(3)
124         YY(4)=YI(3)
125         IF(ABS(XI(1)).GT.ABS(XI(3))) FLIP=.TRUE.
126         GO TO 1170
127 1130    IF(KK.EQ.4) GO TO 1140
128C
129C     HERE FOR MACH LINE INTERSECTING TE AND TIP CHORD
130C
131         XX(1)=XI(2)
132         XX(2)=X(3)
133         XX(3)=XI(3)
134         YY(1)=YI(2)
135         YY(2)=Y(3)
136         YY(3)=YI(3)
137         FLIP=.TRUE.
138         GO TO 1170
139C
140C     HERE FOR MACH LINE INTERSECTING ROOT CHORD AND LE
141C
142 1140    XX(1)=X(1)
143         XX(2)=XI(1)
144         XX(3)=XI(4)
145         YY(1)=Y(1)
146         YY(2)=YI(1)
147         YY(3)=YI(4)
148         GO TO 1170
149C
150C     HERE FOR MACH LINE INTERSECTING ROOT CHORD AND TIP CHORD
151C
152 1150    XX(1)=X(1)
153         XX(2)=X(2)
154         XX(3)=XI(2)
155         XX(4)=XI(4)
156         YY(1)=Y(1)
157         YY(2)=Y(2)
158         YY(3)=YI(2)
159         YY(4)=YI(4)
160         GO TO 1170
161C
162C     HERE FOR MACH LINE INTERSECTING ROOT CHORD AND TE
163C
164 1160    XX(1)=XI(3)
165         XX(2)=X(4)
166         XX(3)=XI(4)
167         YY(1)=YI(3)
168         YY(2)=Y(4)
169         YY(3)=YI(4)
170         FLIP=.TRUE.
171 1170    CALL AREA1 (XX,YY,SAREA,NSUM)
172         AREA(J)=SAREA
173 1180    IF(J.NE.1) GO TO 1190
174         IF(.NOT.FLIP) GO TO 1220
175         AREA(1)=AVT(1+NCON)-AREA(1)
176         GO TO 1220
177 1190    IF(FLIP) GO TO 1200
178         AREA(2)=AVT(1+NCON)-AREA(2)
179 1200    IF(.NOT.HTAIL) GO TO 1210
180         SVHB(1+NCON)=AVT(1+NCON)-(AREA(1)+AREA(2))
181         GO TO 1220
182 1210    SVWB(1+NCON)=AVT(1+NCON)-(AREA(1)+AREA(2))
183 1220 CONTINUE
184      IF(NCON.EQ.1) GO TO 1230
185      NCON=1
186C
187C     TEST FOR NON-STRAIGHT TAPERED VT
188C
189      IF(VTIN(15).EQ.STRA) GO TO 1230
190C
191C     COORDINATES OF OUTBOARD VT PANEL
192C
193      XP(1)=XP(2)
194      YP(1)=YP(2)
195      XP(2)=XP(2)+VTIN(2)*AVT(86)
196      YP(2)=VTIN(4)
197      XP(3)=XP(2)+VTIN(1)
198      YP(3)=VTIN(4)
199      XP(4)=XP(1)+VTIN(5)
200      YP(4)=YP(1)
201      XP(5)=XP(1)
202      YP(5)=YP(1)
203      GO TO 1020
204 1230 IF(.NOT.HTAIL) GO TO 1240
205      VTIN(134+I)=SVHB(1)+SVHB(2)
206      GO TO 1250
207 1240 VTIN(94+I)=SVWB(1)+SVWB(2)
208 1250 CONTINUE
209      IF(HTAIL) GO TO 1260
210C
211C     TEST FOR HT
212C
213      IF(.NOT.HTPL) GO TO 1260
214      HTAIL=.TRUE.
215      NCON=0
216      GO TO 1000
217 1260 VTIN(114+I)=AVT(3)-(VTIN(94+I)+VTIN(134+I))
218      RETURN
219      END
220