Program was written in Basic, specific to the Tandy Color Computer I had at the time. On the next page is an Excel Spreadsheet.
30
REM SPAR LOAD CALCULATION
50
INPUT "ENTER WING SPAN INCHES"; S
70
HS =S/2 'HS IS 1/2 SPAN
90
INPUT "ENTER SPAR DEPTH IN INCHES"; SD
110
INPUT "ENTER SPAR WIDTH IN INCHES"; SW
130
INPUT "THICKNESS OF SPAR CAP"; CT
150
INPUT "WEIGHT OF AIRPLANE IN POUNDS"; W
170
INPUT "DESIGN LOAD FACTOR"; L
190
'HL=LOAD SUPPORTED BY ONE WING PANEL (HALF
TOTAL WEIGHT TIMES THE LOAD FACTOR)
210
HL=W/2*L
230
' RS=LOAD AT WING ROOT
250
RS=HS*(HL/2)
270
REM J IS THE DISTANCE BETWEEN THE SPAR CAPS
290
J=SD-(2*CT)
310
' C IS THE MOMENT OF INERTIA (THE ABILITY OF THE SPAR CROSS SECTION TO
RESIST LOADS)
330
C=(SW*(SD^3-J^3)/12)
350
' E IS THE DISTANCE FROM THE NEUTRAL AXIS (CENTERLINE BETWEEN THE SPAR
CAPS FOR EQUAL CROSS SECTION CAPS)
370
E=SD/2
390
Z=RS/(C/E)
410
'Z IS THE MAXIMUM STRESS IN PSI SUSTAINED BY THE SPAR CAP
430
'LINE 450 ASSUMES 9000 PSI AS THE MODULUS OF RUPTURE OR MAXIMUM STRESS
SPRUCE CAN SUSTAIN WITHOUT FRACTURING. 2500
PSI IS MY BEST GUESS FOR LIGHTWEIGHT BALSA, PERHAPS 4000 FOR VERY DENSE
BALSA.
450
K=9000/Z*I00
470
CLS:
"PRINT"
D0 YOU WANT THE RESULTS
ON THE SCREEN, AS A HARDCOPY
(S/H) OR ARE YOU DONE(D)?"
490
A$=INKEY$
510
IF A$="D" THEN 570
530
IF A$="S" THEN 590
550
IF A$="H" THEN 810 ELSE 490
570
CLS: END
590
CLS: PRINT "WING SPAN IS" ;S
610
PRINT "SPAR DEPTH IS " :SD
630
PRINT "SPAR WIDTH IS " ; SW
650
PRINT "SPAR CAP THICKNESS IS " ;CT
670
PRINT "DESIGN WEIGHT OF AIRPLANE IS ";W
690
PRINT "STRESS AT WING ROOT IS "Z" PSI"
710
PRINT "DESIGN IS "K" % OF DESIGN REQUIREMENTS ASSUMING A LOAD FACTOR
OF";L
730
PRINT "PRESS C TO CONTINUE"
750
B$=INKEY$
770
IF B$="C" THEN 790 ELSE 750
790
GOTO 470
810
CLS: PRINT#-2, "WING SPAN IS ";S
830
PRINT " PRINTING IN PROGRESS"
850
PRINT#-2, "SPAR DEPTH IS ":SD
870
PRINT#-2," SPAR WIDTH IS ";SW
890
PRINT#-2, "SPAR CAP THICKNESS IS ":CT
910
PRINT#-2, "DESIGN WEIGHT OF AIRPLANE IS ";W
930
PRINT#-2, "STRESS AT WING ROOT IS "Z" PSI"
950
PRINT#-2, "DESIGN IS "K" % OF DESIGN
REQUIREMENTS ASSUMING A LOAD FACTOR OF ";L
970
CLS
990
GOTO 470
Sample Data:
WING
SPAN IS 70.41 SPAR DEPTH IS .96875 SPAR WIDTH IS .375
SPAR
CAP THICKNESS IS .125 DESIGN WEIGHT
OF AIRPLANE IS 6 LBS
STRESS
AT WING ROOT IS 9131.1191 PSI
DESIGN IS 98.5640414 % OF DESIGN
REQUIREMENTS ASSUMING A LOAD FACTOR OF 6
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