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A Structural Weight Estimation Program (Sweep) for Aircraft - Vol XI - Flexible Airloads Stand-Alone Program

mxring accelerated flight corditions at high speeds, deflections of 
the lifting surface stnxture terd to ibute the airloads. The result- 
i.ng airlod can be considerably different fran that on 
the of catplete rigidity. TYE redistlüition results fran the 
in streaNise angle-of-attack along the span caused by torsional 
ard deflectims. For a given mach ruz±er, the greater the dynanic 
pressure, greater will be the load redistribution. 
The airloads in the SWEEP program does rwt incli.de the effects of 
aeroelasticity; i.e. , the changes in airload due to 
deflectims. A significant refinanent is obtained by including the added 
effects on loads caused by wing structural flexibility. This is accmplished 
by the use of the stard-alone flexible airloads progræn described herein. 
bbtrnds ard fomulatim aployed in the stad-alone progran are presented in 
Section Il. The progrm description and program usage informtion 
are presented in Sections Ill IV, respectively. 
stand-alone progran requires a substantial mount of extemal 
data. n-ese data cmsist of (I) airplane gea1Etry data identical to that 
used by the airloads mdule (BIETL) in the program, (2) the wing El 
GJ distribution ard elastic location, (3) the specific flight 
condition case data. The specific flight condition case data i.xllde tm 
of flight condition (balancal maneuver, vertical or lateral gust, pitch- 
ing or yawing acceleratim), mach runnber and altitude conbinations, limit 
reneuver load factors, pitching and yawing accelerations, airplane weight 
CG location, and estimated wing weight distrilntion. The progran calculates 
the airload center-of-pressure location for each airplane carponent md 
the airload shear, bending nunent, arxi torsion distributim on wing ard 
anpennage surfaces, all for the specified flight cmdition case.

objective of flexible airloads star+alone progrn, BæcrL, is 
to detemirw airloads m the aiQIane cmponents, the effects 
of wing flexibility. Tl»se loads are detemir»d for a specific flight cordi- 
tion case are used as optional external i.l.tßlt to the SWæ progrzn. 
The *thods are described in order that the subroutines USPANF, 
QUSF, are used in stud-alone progran.