Evaluation of Critical Sting Length on a 7-deg Cone as Determined by Measurements of Dynamic Stability Derivatives and Base Pressure for Mach Numbers 0.2 Through 1.3


Book Description

Wind tunnel tests were conducted to provide sting-support interference information for planning and directing wind tunnel tests at subsonic and transonic Mach numbers. Sting-length effects on dynamic stability derivatives, static pitching moment, and base pressure of a blunt, flat-base 7- deg cone were investigated at Mach numbers 0.2 to 1.3 in the Arnold Engineering Development Center (AEDC) Propulsion Wind Tunnel Facility (PWT). Two frequencies of oscillation, nominally 5.3 and 2.9 Hz, were investigated. The boundary-layer state at the model base was turbulent for all Mach numbers greater than 0.2. The interference effects of two types of model-wake splitter plates were also investigated. The results showed that the critical sting length depended on the Mach number, angle of attack, and type of data used as the interference indicator. A critical sting length of three model diameters was determined to be suitable for all test conditions for the ratio of sting-diameter-to-model-base- diameter (0.22) for this test.




Sting Interference Effects as Determined by Measurements of Dynamic Stability Derivatives, Surface Pressure, and Base Pressure for Mach Numbers 2 Through 8


Book Description

Wind tunnel tests were conducted to provide support interference information for planning and directing wind tunnel tests at supersonic and hypersonic Mach numbers. Sting-length and sting-diameter effects on base and surface pressures of a blunt 6-deg cone with a sliced base were investigated at Mach numbers 2, 3, 5, and 8. Dynamic stability tests on a blunt 7-deg cone were also conducted at Mach numbers 2, 5, and 8. The objectives of the 7-deg cone tests were to define critical sting lengths as determined by the measurement of dynamic stability derivatives, static pitching moment, and base pressure. Two frequencies of oscillation were investigated, and data were obtained for laminar, transitional, and turbulent boundary-layer conditions at the model base. The data from the 6- and 7-deg cone tests showed that the critical sting length depended on the interference indicator, Mach number, angle of attack, state of the model boundary layer, and frequency of oscillation. The critical sting length was generally less for models with turbulent boundary layers than for those with laminar boundary layers. A critical sting length of 2.5 model diameters was determined to be suitable for all test conditions that produced a turbulent boundary layer at or ahead of the model base.




Critical Sting Length as Determined by the Measurement of Pitch-damping Derivatives for Laminar, Transitional, and Turbulent Boundary Layers at Mach Number 3 for Reduced Frequencies of 0.0033 and 0.0056


Book Description

A research program was initiated for the purpose of investigating some of the problem areas in regard to support interference in supersonic wind tunnels. The critical sting length at alpha = 0 was determined by the measurement of pitch-damping derivatives for laminar, transitional, and turbulent boundary layers at the model base. The effect of wedge splitter plates on sting interference was also investigated. By utilizing the small amplitude forced oscillation technique, data were obtained at Mach number 3 on a blunt 7-deg cone for reduced frequencies of 0.0033 and 0.0056. The results showed that the critical sting length with respect to sting interference on pitch-damping data was two model diameters for the two reduced frequencies investigated and was independent of the type of boundary layer at the model base. Decreasing the effective sting length from 3.3 to one model diameter increased the model base pressure substantially and the model surface pressure slightly. The critical sting length for minimal base pressure interference is 2.5 model diameters for this model and these test conditions.




Scientific and Technical Aerospace Reports


Book Description

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.




Government Reports Annual Index


Book Description

Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.







Design for Control of Projectile Flight Characteristics


Book Description

This handbook presents a general survey of the principal factors affecting the flight of projectiles, and describes the methods commonly used for predicting and influencing the flight performance. The coefficients which characterize the aerodynamic forces and moments of a moving body are identified, methods for determining the coefficients applicable to a projectile having a given shape and center of gravity location are described, and the coefficients of a number of projectiles and projectile shapes are given. The use of aerodynamic coefficients in predicting stability, range and accuracy is described. The effects of variations in projectile shape and center of gravity location on range, accuracy and lethality are discussed. Some material on prototype testing and the effects of round-to-round variations in production lots is presented.




Handbook of Supersonic Aerodynamics


Book Description




High-speed Wind Tunnels


Book Description

The importance assumed in recent times by experimental supersonic wind tunnels, as well as the power required, has brought about the need for a study which would permit a comparison of the types tested and the principal theoretical plans.




Low-Speed Wind Tunnel Testing


Book Description

A brand-new edition of the classic guide on low-speed wind tunnel testing While great advances in theoretical and computational methods have been made in recent years, low-speed wind tunnel testing remains essential for obtaining the full range of data needed to guide detailed design decisions for many practical engineering problems. This long-awaited Third Edition of William H. Rae, Jr.'s landmark reference brings together essential information on all aspects of low-speed wind tunnel design, analysis, testing, and instrumentation in one easy-to-use resource. Written by authors who are among the most respected wind tunnel engineers in the world, this edition has been updated to address current topics and applications, and includes coverage of digital electronics, new instrumentation, video and photographic methods, pressure-sensitive paint, and liquid crystal-based measurement methods. The book is organized for quick access to topics of interest, and examines basic test techniques and objectives of modeling and testing aircraft designs in low-speed wind tunnels, as well as applications to fluid motion analysis, automobiles, marine vessels, buildings, bridges, and other structures subject to wind loading. Supplemented with real-world examples throughout, Low-Speed Wind Tunnel Testing, Third Edition is an indispensable resource for aerospace engineering students and professionals, engineers and researchers in the automotive industries, wind tunnel designers, architects, and others who need to get the most from low-speed wind tunnel technology and experiments in their work.