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Sawyer, W. C.

Publications and source records attributed to Sawyer, W. C..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Bodies with noncircular cross sections and bank-to-turn missiles

A development status evaluation is presented for the aerodynamics of missile configurations with noncircular cross-sections and bank-to-turn maneuvering systems, giving attention to cases with elliptical and square cross-sections, as well as bodies with variable cross-sections. The assessment of bank-to-turn missile performance notes inherent stability/control problems. A summary and index are provided for aerodynamic data on monoplanar configurations, including those which incorporate airbreathing propulsion systems.

Jackson, C. M., Jr.↗
NASA NTRS1986

Bodies with noncircular cross sections and bank-to-turn missiles

An evaluation is made of prospective missile applications for noncircular cross section bodies, and of recent developments in bank-to-turn missile configuration aerodynamics. The discussion encompasses cross-flow analysis techniques, as well as study results obtained for bodies with elliptical and square cross sections and with variable cross sections. Attention is given to both the performance advantages and the stability and control problems of bank-to-turn missile configurations; the aerodynamic data presented for monoplanar configurations extend to those incorporating airbreathing propulsion systems.

Jackson, C. M., Jr.↗
NASA NTRS1982

Survey of engineering computational methods and experimental programs for estimating supersonic missile aerodynamic characteristics

This paper presents a survey of engineering computational methods and experimental programs used for estimating the aerodynamic characteristics of missile configurations. Emphasis is placed on those methods which are suitable for preliminary design of conventional and advanced concepts. An analysis of the technical approaches of the various methods is made in order to assess their suitability to estimate longitudinal and/or lateral-directional characteristics for different classes of missile configurations. Some comparisons between the predicted characteristics and experimental data are presented. These comparisons are made for a large variation in flow conditions and model attitude parameters. The paper also presents known experimental research programs developed for the specific purpose of validating analytical methods and extending the capability of data-base programs.

Sawyer, W. C.↗
NASA NTRS1982

An overview of NASA's role in maneuvering missile aerodynamic technology

This paper presents an overview of the role NASA has had and continues to pursue in providing missile aerodynamic technology. In the past, NASA has provided considerable support to the missile industry and the military. The support has generally taken the form of theoretical aerodynamic analyses, experimental studies to provide solutions for specific problems, and the documentation of existing foreign missile systems and domestic missiles. In 1975, NASA shifted its missile-related efforts in aerodynamics from this largely service role to one of conducting more basic research. The areas of research include: innovative methods for roll control of cruciform missiles, airbreathing missiles with maneuver requirements, and an advanced generation of monoplanar missiles for efficient supersonic carriage and delivery.

Sawyer, W. C.↗
NASA NTRS1982

Comprehensive missile aerodynamics programs for preliminary design

Two different classes of missile aeroprediction programs have been recently developed. The first class of programs provides rapid engineering predictions and includes MISSILE1 and MISSILE2 applicable to missile configurations with axisymmetric bodies. The second class of programs consists of the DEMON series, including a simplified version NSWCDM, designed to calculate detailed loadings acting on supersonic missiles which may have non-circular body cross sections. Both classes account for high angles of attack and track vortices from canard or wing section to the tail section. Extensive comparisons with experimental data are presented including nonlinear effects of canard control.

Dillenius, M. F. E.↗
NASA NTRS1981

Experimental and theoretical supersonic lateral-directional stability characteristics of a simplified wing-body configuration with a series of vertical-tail arrangements

An experimental investigation was conducted to provide a systematic set of lateral-directional stability data for a simplified wing-body model with a series of vertical-tail arrangements. The study was made at Mach numbers from 1.60 to 2.86 at nominal angles of attack from -8 to 12 deg and Reynolds number of 8.2 million per meter. Comparisons at zero angle of attack were made with three existing theoretical methods (MISLIFT - a second-order shock expansion and panel method; APAS - a slender body and first order panel method; and PAN AIR - a higher order panel method) and comparisons at angle of attack were made with PAN AIR. The results show that PAN AIR generally provides accurate estimates of these characteristics at moderate angles of attack for complete configurations with either single or twin vertical tails. APAS provides estimates for complete configurations at zero angle of attack. However, MISLIFT only provides estimates for the simplest body-vertical-tail configurations at zero angle of attack.

Lamb, M.↗
NASA NTRS1981

Theoretical and experimental supersonic lateral-directional stability characteristics

A program has been initiated at NASA Langley Research Center to assess several methods for estimation of lateral-directional stability. As a basis for comparison, experimental data are presented for a simple wing-body vertical tail configuration. The methods for estimating the characteristics include a second-order shock expansion and panel method (MISLIFT), a slender body and 'first-order' panel method (APAS), and a 'higher-order' panel method for linearized supersonic flow (PAN AIR). The results show that PAN AIR provides accurate estimates of these characteristics at moderate angles of attack for complete configurations with either single or twin vertical tails. APAS provides estimates for complete configurations at zero angle of attack. However, MISLIFT only provides estimates for the simplest body-vertical tail configurations at zero angle of attack.

Lamb, M.↗
NASA NTRS1981

Control characteristics for wrap-around fins on cruise missiles configurations

This paper presents selected results of a panel loads study conducted as part of the final phase of an extensive investigation of an air-breathing missile concept employing wrap-around aerodynamic surfaces. Typical results for M = 2.36 are presented for the fin load results, plus a brief review of basic results of the previously reported tests. Vapor screen results are also discussed. The present results indicate that the fin load characteristics are nearly identical for planar and curved fins having the same projected planform and would permit the use of planar-surface predictions for supersonic speeds in the preliminary design stages of missiles employing wrap-around curved fins.

Sawyer, W. C.↗
NASA NTRS1980

Wind-tunnel/flight correlation study of aerodynamic characteristics of a large flexible supersonic cruise airplane (XB-701) 2: Extrapolation of wind-tunnel data to full-scale conditions

The results of calculations necessary to extrapolate performance data on an XB-70-1 wind tunnel model to full scale at Mach numbers from 0.76 to 2.53 are presented. The extrapolation was part of a joint program to evaluate performance prediction techniques for large flexible supersonic airplanes similar to a supersonic transport. The extrapolation procedure included: interpolation of the wind tunnel data at the specific conditions of the flight test points; determination of the drag increments to be applied to the wind tunnel data, such as spillage drag, boundary layer trip drag, and skin friction increments; and estimates of the drag items not represented on the wind tunnel model, such as bypass doors, roughness, protuberances, and leakage drag. In addition, estimates of the effects of flexibility of the airplane were determined.

Peterson, J. B., Jr.↗
NASA NTRS1979

Investigation of flow characteristics over missile bodies at supersonic speeds

Three missile body shapes tested at Mach numbers of 1.50, 2.16, and 2.86 with angles of attack up to 30 degrees are described. The flow characteristics for each body shape are examined. The measured aerodynamic forces and moments are presented. The use of flow visualization techniques are described and the results such as vortex effects are discussed.

Barger, R. L.↗
NASA NTRS1979

Pressure distributions on three different cruciform aft-tail control surfaces of a wingless missile at mach 1.60, 2.36, and 3.70 Volume 1: Trapezoidal tail

The results of pressure distribution tests conducted in the Langley Unitary Plan wind tunnel are presented. The data were obtained for three sets of cruciform aft-tail control surfaces on a wingless missile model at Mach numbers of 1.60, 2.36, and 3.70 for angles of attack from -4 degrees to 20 degrees, model roll angles from 0 degrees to 90 degrees, and tail deflections of 0 degrees and 15 degrees. The test Reynolds number used was 6.6 million per meter.

Lamb, M.↗
NASA NTRS1979

Pressure distributions on three different cruciform aft-control surfaces of a wingless missile at Mach 1.60, 2.36, and 3.70. Volume 2: Clipped delta tail

Pressure coefficients were obtained in the Langley Unitary Plan wind tunnel for a wingless missile with a clipped delta tail. The angle of attack was varied from -4 deg to 20 deg, model roll angle was varied from 0 deg to 90 deg in 22.5 deg increments, and tail deflections were 0 deg to - 15 deg. The pressures were measured on two adjacent tail surfaces using 91 pressure orifices per tail surface. Results are presented in plotted and tabular form.

Lamb, M.↗
NASA NTRS1979

Pressure distributions on three different cruciform aft-tail control surfaces of a wingless missile at Mach 1.60, 2.36, and 3.70. Volume 1: Trapezoidal tail

The results of pressure distribution tests conducted in a wind tunnel are presented without analysis. The data were obtained for trapezoidal aft tail control surfaces on a wingless missile model at Mach numbers of 1.60, 2.36, and 3.70 for angles of attack from -4 to 20 deg model roll angles from 0 to 90 deg and tail deflections of 0 and -15 deg. The test Reynolds number used was 6.6 million per meter.

Lamb, M.↗
NASA NTRS1979

Stability and control characteristics of a monoplanar elliptic missile model at Mach numbers from 1.60 to 2.86

An investigation was conducted of a monoplanar maneuverable missile concept having a nose forebody with a circular cross section and a centerbody and afterbody with elliptical cross sections. The tests involved several component changes and were conducted in the low Mach number test section of the Langley Unitary Plan wind tunnel at Mach numbers of 1.60, 2.16, and 2.86, at angles of attack ranging from -4 degs to 28 degs and at sideslip angles ranging from -4 degs to 8 degs. The most significant result was that at the highest Mach number (2.86), the configuration with the infrared nose produced nearly twice the axial force as the same configuration with the radar nose. The cranked wing had a destabilizing effect on the longitudinal stability and had no effect on the lateral-directional stability. The nose strakes had no effect longitudinally and were detrimental to the lateral-directional stability.

Sawyer, W. C.↗
NASA NTRS1978

A ram-air-spoiler roll stabilization device for forward control cruciform missiles

An experimental investigation has been made at supersonic Mach numbers to determine the feasibility of using a ram-air-spoiler roll control device on a typical canard control missile configuration. As a basis for roll control comparisons, conventional aileron controls on the tail fins were also tested. Results are presented which indicate that the addition of nacelles on the missile tail fins resulted in satisfactory roll control effectiveness and only small changes in basic missile stability. The ram-air-spoiler roll control effectiveness is relatively constant over the range of vehicle attitudes and Mach numbers investigated.

Blair, A. B., Jr.↗