71 Matching Results

Search Results

Advanced search parameters have been applied.

Wind-Tunnel Investigation of the Interference Effects during Separation of a 1/40-Scale Model Convair B-58 Airplane and Store at Mach Numbers of 1.41, 1.61, and 2.01

Description: An investigation has been made in the Langley 4- by 4-foot supersonic pressure tunnel to determine the aerodynamic characteristics of a 1/40-sca!e pod-separation model of the Convair B-58 airplane at Mach numbers of 1.41, 1.61, and 2.01. The complete return component and the complete pod with its canard controls were tested, both alone and in the presence of each other, at Mach numbers of 1.61 and 2.01. The complete pod and various combinations of its components were tested alone at Mach numbers of 1.41, 1.61, and 2.01 and also in the presence of the return component at Mach numbers of 1.61 and 2.01. The pod was moved in a systematic series of longitudinal and vertical positions to cover the interference fields. The tests were made at zero sideslip only, for pod angles of attack from -10 deg to 10 deg and return-component angles of attack from -4 deg to 6 deg. The present data report gives the results of the investigation in tabular form.
Date: December 28, 1956
Creator: Driver, Cornelius
Partner: UNT Libraries Government Documents Department

Rocket-Model Measurements of Zero-Lift Damping in Roll of the Bell MX-776 Missile at Mach Numbers from 0.6 to 1.56

Description: The zero-lift damping in roll of the Bell MX-776 missile has been measured by a sting-mounted rocket-model technique at Mach numbers from 0.6 to 1.56. The damping-in-roll data, in general, show no unusual variation with Mach number. Aileron rolling-moment effectiveness derived from these data and previously obtained rolling-effectiveness data appear reasonable,.
Date: December 31, 1953
Creator: Bland, William M., Jr. & Purser, Paul E.
Partner: UNT Libraries Government Documents Department

Investigation of a 1/22-scale model of the Republic F-105 airplane in the Langley 8-foot transonic tunnel: static longitudinal stability and control and performance characteristics at transonic speeds

Description: Report presenting an investigation of the aerodynamic characteristics of various configurations of a model of the Republic F-105 in the transonic tunnel at a variety of Mach numbers. Results regarding lift characteristics, pitching-moment characteristics, zero-lift drag characteristics, maximum lift-drag ratio, flaperon and rudder characteristics, and effective downwash characteristics are provided.
Date: April 26, 1956
Creator: Luoma, Arvo A.
Partner: UNT Libraries Government Documents Department

Stability and control characteristics at low speed of a modified 1/10-scale model of the MX-1554A design

Description: Report presenting an investigation of the low-speed stability and control characteristics of a modified scale model of the MX-1554A design. It employs a triangular wing and triangular stabilizing surfaces. The modifications of the design included an increase in slotted-flap span, a redesigned tip aileron, fuselage tail cone, and speed brakes.
Date: November 19, 1953
Creator: Lockwood, Vernard E. & Solomon, Martin
Partner: UNT Libraries Government Documents Department

Stability and control characteristics at low speed of a 1/10-scale model of MX-1554A design

Description: Report presenting an investigation of the low-speed stability and control characteristics of a scale model of the proposed MX-1554A design. It employs a triangular wing and triangular stabilizing surfaces. Results regarding the effect of wing incidence, tail position, fences, and chord extensions on the longitudinal characteristics are provided.
Date: January 13, 1953
Creator: Lockwood, Vernard E. & Solomon, Martin
Partner: UNT Libraries Government Documents Department

Heat-transfer and pressure measurements from a flight test of the second 1/18-scale model on the Titan intercontinental ballistic missile up to a Mach number of 3.91 and Reynolds number per foot of 23.4 x 10(exp 6) : COORD. No. AF-AM-70

Description: Report presenting heat-transfer and pressure measurements obtained from flight tests of a model of the Titan intercontinental ballistic missile. Turbulent flow was observed over the model throughout the flight with the exception of one station on the nose. Results regarding pressure measurements, heat transfer, and drag measurements are required.
Date: January 29, 1958
Creator: Graham, John B., Jr.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics including effects of wing fixes of a 1/20-scale model of the Convair F-102 airplane at transonic speeds

Description: From Introduction: "Results from the tests in the Langley 4- by 4-foot supersonic pressure tunnel at Mach numbers of 1.61 and 2.01 are presented in reference 1. Reported herein are results obtained from the tests in the Langley 8-foot transonic tunnel of the model with no control deflections at Mach numbers 0.6 to 1.12 for angles of attack up to 34^o
Date: March 18, 1954
Creator: Osborne, Robert S. & Wornom, Dewey E.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of a 0.04956-scale model of the Convair F-102A airplane at Mach numbers of 1.41, 1.61, and 2.01

Description: From Summary: "Tests have been made in the Langley 4- by 4-foot supersonic pressure tunnel at Mach numbers of 1.41, 1.61, and 2.01 of various arrangements of a 0.04956-scale model of the Convair F-102A airplane with faired inlets. Tests made of the model equipped with a plain wing, a wing with 6.4 percent conical camber, and a wing with 15 percent conical camber. Body modifications including an extended nose, a modified canopy, and extended afterbody fillets were evaluated. In addition, the effects of a revised vertical tail and two different ventral fins were determined. The results indicated that the use of cambered wings resulted in lower drag in the lift-coefficient range above 0.2. This range, however, is above that which would generally be required for level flight; hence, the usefulness of camber might be confined to increased maneuverability at the higher lifts while its use may be detrimental to the high-speed (low-lift) capabilities."
Date: September 30, 1955
Creator: Spearman, M. Leroy & Driver, Cornelius
Partner: UNT Libraries Government Documents Department

Investigation of the Low-Speed Stability and Control Characteristics of a 1/10-Scale Model of the Convair YF-102 Airplane in the Langley Free-Flight Tunnel

Description: From Summary: "An investigation of the low-speed, power-off stability and control characteristics of a 1/10-scale model of the Convair YF-102 airplane has been made in the Langley free-flight tunnel. The model was flown over a lift-coefficient range from 0.5 to the stall in its basic configuration and with several modifications involving leading-edge slats and increases in vertical-tail size. Only relatively low-altitude conditions were simulated and no attempt was made to determine the effect of freeing the controls."
Date: November 18, 1953
Creator: Johnson, Joseph L., Jr. & Boisseau, Peter C.
Partner: UNT Libraries Government Documents Department

Qualitative Results from a Flight Investigation to Determine Aileron Effectiveness of Two Rocket-Propelled 1/20-Scale Models of the MX -76 Missile

Description: Free-flight tests of two rocket-propelled l/20-scale models of the Bell MX-776 missile have been conducted to obtain measurements of the aileron deflection required to counteract the induced rolling moments caused by combined angles of attack and sideslip and thus to determine whether the ailerons provided were capable of controlling the model at the attitudes produced by the test conditions. Inability to obtain reasonably steady-state conditions and superimposed high-frequency oscillations in the data precluded any detailed analysis of the results obtained from the tests. For these reasons, the data presented are limited largely to qualitative results.
Date: October 20, 1955
Creator: Stevens, Joseph E.
Partner: UNT Libraries Government Documents Department

Investigation of Static Stability and Drag Characteristics of a 1/10-Scale Model of the Avco Booster Vehicle at Mach Numbers of 1.60 and 2.00, Coord. No. AF-AM-58

Description: An investigation has been conducted in the Langley Unitary Plan Wind tunnel to determine the static stability and drag characteristics of a 1/10-scale model of the AVCO booster vehicle. The tests were made at a constant Reynolds number, based on maximum nose diameter, of 1.09 x 10(exp 6)6 at Mach numbers of 1.60 and 2.00.
Date: May 10, 1957
Creator: Church, James D. & Sista, Lawrence M.
Partner: UNT Libraries Government Documents Department

Dynamic Investigation of Release Characteristics of a Streamlined Internal Store from a Simulated Bomb Bay of the Republic F-105 Airplane at Mach Numbers of 0.8, 1.4, and 1.98, Coord. No. AF-222

Description: An investigation has been conducted in the 27- by 27-inch preflight jet of the Langley Pilotless Aircraft Research Station at Wallops Island, Va., of the release characteristics of a dynamically scaled streamlined-type internally carried store from a simulated bomb bay at Mach numbers M(sub o) of 0.8, 1.4, and 1.98. A l/17-scale model of the Republic F-105 half-fuselage and bomb-bay configuration was used with a streamlined store shape of a fineness ratio of 6.00. Simulated altitudes were 3,400 feet at M(sub o) = 0.8, 3,400, and 29,000 feet at M(sub o) = 1.4, and 29,000 feet at M(sub o) = 1.98. At supersonic speeds, high pitching moments are induced on the store in the vicinity of the bomb bay at high dynamic pressures. Successful ejections could not be made with the original configuration at supersonic speeds at near sea-level conditions. The pitching moments caused by unsymmetrical pressures on the store in a disturbed flow field were overcome by replacing the high-aspect-ratio fin with a low-aspect-ratio fin that had a 30-percent area increase which was less subject to aeroelastic effects. Release characteristics of the store were improved by orienting the fins so that they were in a more uniform flow field at the point of store release. The store pitching moments were shown to be reduced by increasing the simulated altitude. Favorable ejections were made at subsonic speeds at near sea-level conditions.
Date: January 1, 1956
Creator: Lee, John B.
Partner: UNT Libraries Government Documents Department

Investigation of the Effects of Propeller Operation on the Low-Speed Stability and Control Characteristics of a 1/6-Scale Model of a Revised Configuration of the Republic XF-84H Airplane

Description: An investigation was made to determine the static longitudinal and lateral stability and control characteristics of a l/6-scale model of the revised Republic XF-84H airplane with and without the propeller operating. The model had a 40deg swept wing of aspect ratio 3.45 and was equipped with a thin, three-blade supersonic-type propeller. Modifications incorporated in the revised model included a raised horizontal tail, increased rudder size, wing fences at 65 percent semispan, and a modified wing leading edge outboard of the fences. The test results for flap-retracted and flap-deflected conditions indicated that the revised configuration should be satisfactory for most normal flight conditions provided the angle of attack does not exceed the angle for pitch-up. An abrupt pitch-up tendency of the model was evident for the zero thrust condition above approximately 15' angle of attack. Although the effects of power were destabilizing, power-on longitudinal stability was satisfactory through the angle-of-attack range for which the model was stable with zero thrust. Above the angle of attack for pitch-up, an uncontrollable left roll-off tendency would be expected with power on and slats retracted. Projection of wing slats or use of leading-edge chord-extensions with only the left extension drooped were found beneficial in controlling the roll-off tendency with power on; however the most effective means found was projection of only the left slat.
Date: September 4, 1953
Creator: Sleeman, William C., Jr.
Partner: UNT Libraries Government Documents Department

Investigation in the Langley Free-Flight Tunnel of the Low-Speed Stability and Control Characteristics of a 1/10-Scale Model Simulating the Convair F-102A Airplane

Description: An investigation of the low-speed, power-off stability and control characteristics of a 1/10-scale model simulating the Convair F-102A airplane has been made in the Langley free-flight tunnel. The model in its basic configuration and with two modifications involving leading- edge slats and an increase in vertical-tail size was flown through a lift-coefficient range from 0.7 to the stall. Only relatively low-altitude conditions were simulated. The longitudinal stability characteristics of the model were considered satisfactory for all conditions investigated. The lateral stability characteristics were considered satisfactory for the basic configuration over the lift-coefficient range investigated, except near the stall, where large values of static directional instability caused the model to be directionally divergent. An 80-percent increase in vertical-tail area increased the angle of attack at which the model became directionally divergent. The longitudinal and lateral control characteristics were generally satisfactory. Although the adverse sideslip characteristics for the model were considered acceptable over the angle-of-attack range, analysis indicates that the adverse sideslip characteristics of the airplane may be objectionable at high angles of attack.
Date: February 7, 1955
Creator: Boisseau, Peter C.
Partner: UNT Libraries Government Documents Department

Low-Speed Investigation of the Static Lateral Stability and Control Characteristics of a 1/6-Scale Model of the Republic XF-84H Airplane with the Propeller Operating

Description: An investigation was made to determine the static lateral stability and control characteristics of a l/6-scale model of the Republic XF-84H airplane with the propeller operating. The model had a 40deg swept wing of aspect ratio 3.45 and had a thin 3-blade supersonic-type propeller. Many modifications to the basic configuration were investigated in attempts to alleviate lateral and directional trim problems which appeared to be associated with propeller slipstream rotation. Although significant benefits were realized with several modifications, none of those tested would be expected to afford satisfactory behavior for all normal flight conditions. A marked left-wing roll-off tendency was indicated at high angles of attack for the basic model configuration. Projection of only the left slat was the most effective remedy found for this problem with the propeller operating. The use of differential wing-flap deflection also appeared to offer a promising means for reducing the roll-off tendency with power on. The large sidewash over the vertical tail, associated with slip- stream rotation, severely restricted the conditions for which directional , trim could be maintained. A small triangular dorsal fin, oriented opposite to the slipstream rotation, was found very effective in reducing the adverse sidewash flow at the tail.
Date: June 25, 1953
Creator: Sleeman, William C., Jr. & Morrison, William D., Jr.
Partner: UNT Libraries Government Documents Department

Concluding Report of Free-Spinning, Tumbling, and Recovery Characteristics of a 1/18-Scale Model of the Ryan X-13 Airplane, Coord. No. AF-199

Description: An investigation has been completed in the Langley 20-foot free-spinning tunnel on a l/18-scale model of the Ryan X-13 airplane to determine its spin, recovery, and tumbling characteristics, and to determine the minimum altitude from which a belly landing could be made in case of power failure in hovering flight. Model spin tests were conducted with and without simulated engine rotation. Tests without simulated engine rotation indicated two types of spins: one, a slightly oscillatory flat spin; and the other, a violently oscillatory spin. Tests with simulated engine rotation indicated that spins to the left were fast rotating and steep and those to the right were slow rotating and flat. The optimum technique for recovery is reversal of the rudder to against the spin and simultaneous movement of the ailerons to full with the spin followed by movement of the elevators to neutral after the spin rotation ceases. Tumbling tests made on the model indicated that although the Ryan X-13 airplane will not tumble in the ordinary sense (end-over-end pitching motion), it may instead tend to enter a wild gyrating'motion. Tests made to simulate power failure in hovering flight by dropping the model indicated that the model entered what appeared to be a right spin. An attempt should be made to stop this motion immediately by moving the rudder to oppose the rotation (left pedal), moving the ailerons to with the spin (stick right), and moving the stick forward after the spin rotation ceases to obtain flying speed for pullout. The minimum altitude required for a belly landing in case of power failure in hovering flight was indicated to be about 4,200 feet.
Date: March 25, 1957
Creator: Bowman, James S., Jr.
Partner: UNT Libraries Government Documents Department

A Cartesian grid embedded boundary method for Poisson`s equation on irregular domains

Description: The authors present a numerical method for solving Poisson`s equation, with variable coefficients and Dirichlet boundary conditions, on two-dimensional regions. The approach uses a finite-volume discretization, which embeds the domain in a regular Cartesian grid. They treat the solution as a cell-centered quantity, even when those centers are outside the domain. Cells that contain a portion of the domain boundary use conservation differencing of second-order accurate fluxes, on each cell volume. The calculation of the boundary flux ensures that the conditioning of the matrix is relatively unaffected by small cell volumes. This allows them to use multi-grid iterations with a simple point relaxation strategy. They have combined this with an adaptive mesh refinement (AMR) procedure. They provide evidence that the algorithm is second-order accurate on various exact solutions, and compare the adaptive and non-adaptive calculations.
Date: January 1997
Creator: Johansen, H. & Colella, P.
Partner: UNT Libraries Government Documents Department

Detonation propagation and Mach stem formation in PBXN-9

Description: PBXN-9 is an explosive that is less sensitive to certain insults, yet retains a high level of performance. As a result, PBXN-9 has been considered as an interim insensitive high explosive for conventional munitions systems. Certain of these systems incorporate wave control methodologies that require some form of reactive flow representation to achieve accurate predictions of the wave propagation. The authors have continued the use of Detonation Shock Dynamics (DSD) as a means to approximately account for reactive flow effects, yet retain the efficiency necessary for the munitions design process. To use DSD, they have taken the approach to calibrate explosives by measuring the detonation velocity as a function of local wave curvature. The DSD calibration, including the appropriate boundary conditions, can then be used to predict wave propagation in complex situations such as around obstacles, following wave-wave collisions, and so on. This paper describes the DSD calibration for PBXN-9, along with the methodologies used to obtain it, for both convergent and divergent flow (positive and negative wave curvatures). During the course of the calibration for convergent flow, Mach stem formation is observed in wave reflection experiments. The characteristics of the Mach stem formation and the subsequent growth are analyzed, presented and compared to similar measurements on other explosives. Illustrative examples of the use of DSD to predict wave propagation are provided.
Date: September 1, 1997
Creator: Hull, L.M.
Partner: UNT Libraries Government Documents Department

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

Description: 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.
Date: February 9, 1958
Creator: Fischetti, Thomas L.
Partner: UNT Libraries Government Documents Department

Effects of Fuselage Modifications on the Drag Characteristics of a 1/20-Scale Model of the Convair F-102 Airplane at Transonic Speeds

Description: From Summary: "An investigation has been conducted in the Langley 8-foot transonic tunnel to determine the effects of several fuselage modifications on the transonic drag-rise characteristics of a 1/20-scale model of the Convair F-102 airplane. Tests covered an angle-of-attack range from 0 degrees to about 10 degrees and a Mach number range from 0.60 to 1.14."
Date: November 2, 1954
Creator: Kelly, Thomas C. & Osborne, Robert S.
Partner: UNT Libraries Government Documents Department

Investigation of Incipient Spin Characteristics of a 1/35-Scale Model of the Convair F-102A Airplane, Coord. No. AF-AM-79

Description: From Summary: "Incipient spin characteristics have been investigated on a 1/35-scale dynamic model of the Convair F-102A airplane. The model was launched by a catapult apparatus into free flight with various control settings, and the motions obtained were photographed. The model was ballasted for the combat loading. All tests were made with the speed brakes and landing gear retracted, and engine effects were not simulated."
Date: February 11, 1958
Creator: Healy, Frederick M.
Partner: UNT Libraries Government Documents Department

Free-Flight-Tunnel Investigation of the Dynamic Stability and Control Characteristics of a Chance Vought F7U-3 Airplane in Towed Flight

Description: "As part of a program to determine the feasibility of using a fighter airplane as a parasite in combination with a Consolidated Vultee RB-36 for long-range reconnaissance missions (project FICON), an experimental investigation has been made in the Langley free-flight tunnel to determine the dynamic stability and control characteristics of a 1/17.5-scale model of a Chance Vought F7U-3 airplane in several tow configurations. The investigation consisted of flight tests in which the model was towed from a strut in the tunnel by a towline and by a direct coupling which provided complete angular freedom. The tests with the direct coupling also included a study of the effect of spring restraint in roll in order to simulate approximately the proposed full-scale arrangement in which the only freedom is that permitted by the flexibility of the launching and retrieving trapeze carried by the-bomber" (p. 1).
Date: April 8, 1952
Creator: Grana, David C. & Shanks, Robert E.
Partner: UNT Libraries Government Documents Department