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Results for “STABILITY - LATERAL AND DIRECTIONAL - DYNAMIC”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Forebody and vertical stabilizer effects on directional stability of a reusable LOX/RP (061) booster AR 12161-2

Results are presented of a wind tunnel test on the directional stability of space shuttle booster configurations. The test was conducted at the 14-inch trisonic tunnel starting 6 December 1971 and continued through 11 December 1971 for a total of 66 occupancy hours. Configurations tested included a cylindrical body with two axisymmetrical noses, one with and without canopy, one delta wing, located in two positions, five vertical tails (including a V tail), two having split rudders, ventral fins, two sets of chines, three airbreathing engine pods, and rocket engine shrouds. The model scale was 0.003366.

Roth, C. E.↗
NASA NTRS1952

Wind-tunnel Investigation of the Contribution of a Vertical Tail to the Directional Stability of a Fighter-type Airplane

Contributions of vertical tail and fuselage to directional stability are determined from pressure distributions measured over wide ranges of angle of attack and angle of yaw with stabilizer in each of three vertical positions, with stabilizer removed and with both stabilizer and vertical tail removed. Results point out inadequacies of current design methods and show that more accurate methods must treat separately contributions of vertical tail, fuselage area above stabilizer, and fuselage area below stabilizer.

LOADS, STEADY - TAIL↗
NASA NTRS1992

A computational study on directional stability of chine-shaped forebodies at high-alpha

CFD is employed to study the flowfields over chine-shaped forebodies at low-speed high-angle-of-attack conditions with sideslip. This study is conducted to define forebody geometries that provide good directional stability characteristics under these conditions. An analytically defined generic forebody model is developed and a systematic examination of forebody shapes is performed to determine which shapes promote a positive contribution to directional stability at high-alpha. Results of the initial parametric study and some guidelines for aerodynamic design to promote positive directional stability are presented.

Ravi, R.↗
NASA NTRS1976

System for imposing directional stability on a rocket-propelled vehicle

An improved system for use in imposing directional stability on a rocket-propelled vehicle is described. The system includes a pivotally supported engine-mounting platform, a gimbal ring mounted on the platform and adapted to pivotally support a rocket engine and an hydraulic actuator connected to the platform for imparting selected pivotal motion. An accelerometer and a signal comparator circuit for providing error intelligence indicative of aberration in vehicle acceleration is included along with an actuator control circuit connected with the actuator and responsive to error intelligence for imparting pivotal motion to the platform. Relocation of the engine's thrust vector is thus achieved for imparting directional stability to the vehicle.

Perkins, H.↗
NASA NTRS1958

Estimation of Directional Stability Derivatives at Small Angles and Subsonic and Supersonic Speeds

Methods are presented for estimating the directional stability derivative increments contributed by the stabilizing surfaces of subsonic and supersonic aircraft. These methods are strictly applicable at zero angle of attack and small angles of sideslip. The procedure of totaling the incremental coefficients to obtain an estimation of the total empennage side-force and yawing-moment coefficient derivatives is also shown, together with numerical examples. A correlation is presented between estimated and experimental incremental coefficients which indicates that the methods of this report generally estimate the increment of side force gained by the addition of a panel to within +/-10 percent of the experimental value while the yawing-moment increment is generally estimated to within +/-20 percent. This is true for both subsonic and supersonic Mach numbers. An example application of the methods to one of the problems in directional stability, that of minimizing the effect of Mach number on the side-force coefficient derivative of the empennage, is discussed.

Goodwin, Frederick K.↗
NASA NTRS1959

Estimation of Directional Stability Derivatives at Moderate Angles and Supersonic Speeds

A study of some of the important aerodynamic factors affecting the directional stability of supersonic airplanes is presented. The mutual interference fields between the body, the lifting surfaces, and the stabilizing surfaces are analyzed in detail. Evaluation of these interference fields on an approximate theoretical basis leads to a method for predicting directional stability of supersonic airplanes. Body shape, wing position and plan form, vertical tail position and plan form, and ventral fins are taken into account. Estimates of the effects of these factors are in fair agreement with experiment.

Kaattari, George E.↗
NASA NTRS1999

Application of Forebody Strakes for Directional Stability and Control of Transport Aircraft

A brief overview of a cooperative NASA/Boeing research effort, Strake Technology Research Application to Transport Aircraft (STRATA), intended to explore the potential of applying forebody strake technology to transport aircraft configurations for directional stability and control at low angles of attack, is presented. As an initial step in the STRATA program, an exploratory wind-tunnel investigation of the effect of fixed forebody strakes on the directional stability and control characteristics of a generic transport configuration was conducted in the NASA Langley 12-Foot Low-Speed Wind Tunnel. Results of parametric variations in strake chord and span, as well as the effect of strake incidence, are presented. The use of strakes for yaw control is also discussed. Results emphasize the importance of forebody/fuselage crossflow in influencing strake effectiveness. Strake effectiveness is also seen to be directly related to its span, but less sensitive to chord; a very short-chord strake with sufficient span can have a significant effect.

Shah, Gautam H.↗
NASA NTRS1953

Wind-tunnel investigation of the effects of various dorsal-fin and vertical-tail configurations on the directional stability of a streamlined body at transonic speeds : transonic-bump method

Yawing-moment coefficients were obtained for several dorsal-fin and vertical-tail configurations in combination with a streamlined body through a large angle-of-sideslip range and a Mach number range of 0.59 to 1.11. The results indicated that dorsal fins improved the directional stability characteristics of the body alone and the body-vertical-tail configuration. A ring tail was more effective at small angles of sideslip and less effective at large angles of sideslip than a tapered low-aspect-ratio vertical tail.

TAIL-BODY COMBINATIONS - MISSILES↗
NASA NTRS1991

A computational study of the F-5A forebody emphasizing directional stability

CFD has been used to study the F-5A forebody flowfield at high angle-of-attack combined with sideslip. The classic wind tunnel experiment demonstrating the dominant contribution of the F-5A forebody to directional stability at high angle-of-attack has been simulated computationally over an angle-of-attack range from 10 deg to 45 deg. The key wind tunnel trend for C (n-beta) was obtained computationally using the code known as cfl3d to solve the Reynolds' equations using a modified form of the Baldwin-Lomax turbulence model. The computations provide detailed and fascinating insights into the physics of flowfield. The results of the investigation show that CFD has reached a level of development where computational methods can be used for high angle-of-attack aerodynamic design.

Mason, William H.↗
NASA NTRS1959

Effect of Flow Incidence and Reynolds Number on Low-Speed Aerodynamic Characteristics of Several Noncircular Cylinders with Applications to Directional Stability and Spinning

The aerodynamic characteristics of several noncircular two-dimensional cylinders with axes normal to the stream at various flow incidences (analogous to angles of attack of a two-dimensional airfoil and obtained by rotating the cylinders about their axes) for a range of Reynolds numbers have been determined from low-speed wind-tunnel tests. The results indicate that these parameters have rather large effects on the drag and side force developed on these cylinders. The side force is especially critical and very often undergoes a change in sign with a change in Reynolds number. Since the flow incidences correspond to combined angles of attack and sideslip in the crossflow plane of three-dimensional bodies, these two-dimensional results appear to have strong implications with regard to directional stability of fuselages at high angles of attack. These implications, along with those associated with the spin-recovery characteristics of aircraft, are briefly discussed.

Polhamus, Edward C.↗
NASA NTRS1946

Flight Measurements of the Directional Stability and Control of a P-51D Airplane with a Horn-Balanced Rudder as Compared with Previously Tested Vertical-Tail Configurations

At the request of the Air Materiel Command, Army Air Forces, flight tests were conducted on a P-5lD-20-NA (AAF No. 44-63826) airplane equipped with a horn-balanced rudder. This rudder was fitted with an unbalancing tab as was the original product fan rudder. Tests were made both with the unbalancing tab in operation and with the unbalancing tab locked. The modification to the original vertical tail consisted of removing the cap from the top of the fin and adding 1.91 square feet of area to the rudder as the horn balance and 0.82 square foot of area to the top of the rudder aft of the hinge line. A comparison of the directional stability and control characteristics of the P-51D airplane with three different vertical-tail configurations - the horn balance, original production, and extended tail (with unbalancing tab locked) configurations are presented herein. The tests of the horn-balanced rudder were conducted at the Langley Laboratory in 1945. The tests of the original-tail configuration were previously conducted at the Ames Aeronautical Laboratory. Tests of the extended-tail configuration were conducted at the Langley Laboratory and are reported.

Mungall, Robert G.↗