6926475955

wjpefcr rtkcal airfoil sections has be en performed, by using the Computer codę USTF3 which »łves the unsteedy 3D fułl potential equation by a two-step semi-implicit time marching finita difference technique. In order to correct the mean staady-state location and strength of the shock wave, a 20 strip turbulent boundary łayer technique has been incorpo-rated into USTF3.

84-1624

Actńre Suppresaion of Aeroelastic Instabilities on a Forward-Swept Wing

T.E. Noll. F.E. Eastep.and R A. Calico Air Force Wright Aeronautical Labs.. Wright-Patter* son AFB, OH. J. Aircraft. 21 (3). PP 202-208 (Mar 1984) 16 figs, 17refs

Key Words: Aircraft wings, Active vibration control, Wing Stores

Anelytical studies were conducted to investigate the poten-tiii of using feedback control systems for preventing multiple aeroelastic instabilities occurring simuttaneoudy in close proKimrty on a forward-swept wing configuration. With the addition of wing mounted external Stores, the dassical bending/torsion flutter instability can be driven to lower airspeeds into the vicinity of aeroelastic instabilities such as dtvergence and body freedom flutter morę commonly assocr-ated with a forward-swept wing. For these studies a typical forward-swept wing configuration. adversely mass balanced to craete dynamie characteristics similar to those caused by edding »xternel Stores, was investigated.

84-1625

Aerodynamic Characteristics, Including Effect of Body Słiape, of a Mach 6 Aircraft Concept

G.D. Riebe

NASA Langley Res. Ctr., Hampton. VA. Rept. No. L-15675, NASA-TP-2235. 32 pp (Dec 1983) N84-13164

Key Words: Aer ody nemie k>ads. Geometrie effects, Aircraft

Longltudinal aer ody nam ic characteristics fer a hydrogen-fueied hypersonie trsn*>ort concept at Mach 6 ara presented. The model components contitt of four bodies with idantical longłtudlnal aree distributions but different cross-sectional shepes and widths, e wing. horizontal and yerticel taili, and e set of wing-mounted nacelles almulated by slid bodies on the wing upper surface. Lłft-drag ratios were found to be only slightly affected by fuselage planform width or cross sectionel shape.

84-1626

Numerical Cale u la tron of Ungtesdy Tren eonie Poten-tial Flow over Three-Dimensional Wings with OsciI-lating Control Surfaces

K. Isogai and K. Suetsugu

Natl. Aerospace Lab.. Tokyo. Japan, AIAA J.. 22 (4). pp 478-485 (Apr 1984) 8 figs. 23 refs

Key Words: Aircraft wings. A er ody nemie loads

Numerical calculations of the unsteedy transonic potential flow over three-dimensional wings with oscilleting control surfaces are performed. For this purpose, a newgrid system, which is appropriate for solving the control surface problems. is introduced into the Computer codę USTF3, which solves the unsteedy three-dimensional fuli potential equation by a two-step semi-implicit time-marching technique. To validate the codę, the unsteady pressure distributions on the NLR swept tapered wing with en inboard control surface and on the RAE swept tapered wing with a part-spen control surface are calculated and compared with those of ex i sting theories and experimental data.

84-1627

A Method for Predicting Low-Speed Aerodynaraic Characteristics of Transport Aircraft

L.E. Murillo and J.H. McMasters Boeing Commercial Airplane Co., Seattle, WA, J. Aircraft. 21 (3). pp 168-174 (Mar 1984) 12 figs. 4 refs

Key Words: Aircraft, A er ody nam ic loads. Computer pro-grams

A preliminary design level methodology for predictlr^ the global aerodynamic characteristics of tran*>ort aircraft in low-speed/high-lłft configurations has been developed, besed on recent edvances in oomputational aerodynemics and analysis methods. The new method involvestwo economical, u ser oriented, Computer programi. One, an advanced lifting-surface theory for the potential flow anelyslsof swept-wlng/ body combinations with muhhelement high-ltft devices, provides the basie theoretical structure. The second program combines potential flow analysis results with aveileble data from prevk>us airplane models to predict the performance of new designs.

84-1628

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