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At least 37 records · Page 2

Transonic-Wind-Tunnel Tests of the Aerodynamic Characteristics of a 0.15-Scale Model of the North American Aviation 255-Inch Fin-Stabilized External Store, Coord No. AF-AM-4

An investigation has been made in the Langley 8-foot transonic tunnels on the aerodynamic characteristics of a 0.15-scale model of the North American Aviation 255-inch fin-stabilized external store over a maximum Mach number range of 0.60 to 1.2 and on the effects of mounting lugs, of fin orientation, of fin aspect ratio, and of fixed-transition. The Reynolds number (based on a body length of 37.50 inches) varied from 9.8 x 10(exp 6) to 13.1 x 10(exp 6). The results indicate that the static margin of the finned store at low lift coefficients was only 9 percent of body length at subsonic Mach numbers and was reduced to zero at a Mach number of 1.0, Increasing the fin aspect ratio from 1.82 to 2.41 increased the subsonic static margin to 18 percent and provided a minimum margin of 9 percent near a Mach number of l.O. Store mounting lugs or fin orientation had only small effects on the aerodynamic characteristics of the basic store.

Fischetti, Thomas L.↗

Aerodynamic Loads on an External Store Adjacent to a 45 Degree Sweptback Wing at Mach Numbers from 0.70 to 1.96, Including an Evaluation of Techniques Used

Aerodynamic forces and moments have been obtained in the Langley 9- by 12-inch blowdown tunnel on an external store and on a 45 degree swept-back wing-body combination measured separately at Mach numbers from 0.70 to 1.96. The wing was cantilevered and had an aspect ratio of 4.0; the store was independently sting-mounted and had a Douglas Aircraft Co. (DAC) store shape. The angle of attack range was from -3 degrees to 12 degrees and the Reynolds number (based on wing mean aerodynamic chord) varied from 1.2 x10(6) to 1.7 x 10(6). Wing-body transonic forces and moments have been compared with data of a geometrically similar full-scale model tested in the Langley 16-foot and 8-foot transonic tunnels in order to aid in the evaluation of transonic-tunnel interference. The principal effect of the store, for the position tested, was that of delaying the wing-fuselage pitch-up tendency to higher angles of attack at Mach numbers from 0.70 to 0.90 in a manner similar to that of a wing chord extension. The most critical loading condition on the store was that due to side force, not only because the loads were of large magnitude but also because they were in the direction of least structural strength of the supporting pylon. These side loads were greatest at high angles of attack in the supersonic speed range. Removal of the supporting pylon (or increasing the gap between the store and wing) reduced the values of the variation of side-force coefficientwith angle of attack by about 50 percent at all test Mach numbers, indicating that important reductions in store side force may be realized by proper design or location of the necessary supporting pylon. A change of the store skew angle (nose inboard) was found to relieve the excessive store side loads throughout the Mach number range. It was also determined that the relative position of the fuselage nose to the store can appreciably affect the store side forces at supersonic speeds.

Guy, Lawrence D↗

Effects of the Spanwise, Chordwise, and Vertical Location of an External Store on the Aerodynamic Characteristics of a 45 Degree Sweptback Tapered Wing of Aspect Ratio 4 at Mach Numbers of 1.41, 1.62, and 1.96

An investigation has been made in the Langley 9- by 12-inch supersonic blowdown tunnel to determine the effects of external-store location on the lift, drag, and pitching-moment characteristics of a 45 degree sweptback wing at Mach numbers of 1.41, 1.62, and 1.96. The spanwise, chordwise, and vertical location of a Douglas-Aircraft Company, Inc., store of fineness ratio 8.58 was systematically varied over the outer 60 percent of the wing semispan. A brief investigation of strut sweep angle was also made. The test Reynolds number based on the wing mean aerodynamic chord ranged from 1.3 x 10(exp 6) to 1.5 x 10(exp 6).

Jacobsen, Carl R.↗

Aeroelastic tailoring of composite wings with external stores

The use of an integrating matrix solution procedure allows the aeroelastic stability of a large number of wing/store combinations to be studied with relative speed and accuracy. Results are presented which show the effects of tailoring the orientation of the plies of laminated composite wings when external stores are present. The stores utilized take the form of concentrated masses that are varied in terms of size and location, and combinations of stores are also studied. It is seen that there are cases for which small changes in the laminate can produce large changes in the aeroelastic stability boundary, and for such situations care should be used in tailoring a wing. For a given wing, the choice fiber angle to optimize the aeroelastic performance is quite sensitive to both the size and location of the store.

Green, J. A.↗

Effects of external stores on the air combat capability of a delta wing fighter

Delta wing point-design fighters with two pylon mounted missiles and aft tail controls (similar to several Soviet designs) have been investigated for a Mach number range from about 0.6 to 2.0. Whereas minimum drag penalties that are expected with the addition of external stores do occur, the effects at higher lifts, corresponding to maneuvering flight, are less severe and often favorable. The drag-due-to-lift factor is less with stores on although the lift curve slope is unaffected. The longitudinal stability level is reduced by the addition of stores while the pitch control effectiveness is unchanged. The directional stability was generally reduced at subsonic speeds and increased at supersonic speeds by the addition of stores but sufficiently high stability levels are obtainable that are compatible with the longitudinal maneuvering limits. Some examples of the potential maneuvering capability in terms of normal acceleration and turn radius are included.

Spearman, M. L.↗

Summary of Low-Lift Drag and Directional Stability Data from Rocket Models of the Douglas XF4D-1 Airplane with and without External Stores and Rocket Packets at Mach Numbers from 0.8 to 1.38 TED No. NACA DE-349

At the request of the Bureau of Aeronautics, Department of the Navy, an investigation at transonic and low supersonic speeds of the drag and longitudinal trim characteristics of the Douglas XF4D-1 airplane is being conducted by the Langley Pilotless Aircraft Research Division. The Douglas XF4D-1 is a jet-propelled, low-aspect-ratio, swept-wing, tailless, interceptor-type airplane designed to fly at low supersonic speeds. As a part of this investigation, flight tests were made using rocket- propelled 1/10- scale models to determine the effect of the addition of 10 external stores and rocket packets on the drag at low lift coefficients. In addition to these data, some qualitative values of the directional stability parameter C(sub n beta) and duct total-pressure recovery are also presented.

Mitcham, Grady L.↗