Engineering topics

Spearman, M. L.

Publications and source records attributed to Spearman, M. L..

At least 55 records · Page 3

NASA NTRS1983

Historical development of worldwide guided missiles

The development of missiles from early history to present time is put in perspective. The influence of World War II in accelerating the development of guided missiles, particularly through German scientists, is discussed. The dispersion of German scientists to other countries and the coupling of their work with native talent to develop guide missiles is traced. Particular emphasis is placed on the evolution of the missile in the U.S. and the U.S.S.R. Since the Soviets possess what is probably the world's most complete array of dedicated missile system types, their known inventory is reviewed. Some philosophical observations of missile design trends and missile purposes are made as related to the interests of various countries.

Spearman, M. L.↗

NASA NTRS1983

Historical development of worldwide supersonic aircraft

Some major milestones in the progression of airplane speeds from subsonic to supersonic are traced. Historical background is included on work done prior to the Twentieth Century, but the major emphasis is on the Twentieth Century developments after the man carrying airplane became a practical reality. The techniques of increasing airplane speed revolve around means of increasing the propulsive force and means of reducing the airframe resistance (drag). With the changes in speed, the attendant changes in flow patterns due to the compressibility of air introduce some aerodynamic problems. In addition, geometric changes introduced to combat the effects of compressibility also promote aerodynamic problems. Some of the solutions to these problems are illustrated, and many design features that evolved are discussed.

Spearman, M. L.↗

NASA NTRS1983

Some historical trends in the research and development of aircraft

A survey of some trends in aircraft design was made in an effort to determine the relation between research, development, test, and evaluation (RDT and E) and aircraft mission capability, requirements, and objectives. Driving forces in the history of aircraft include the quest for speed which involved design concepts incorporating jet propulsion systems and low drag features. The study of high speed design concepts promoted new experimental and analytical research techniques. These research techniques, in turn, have lead to concepts offering new performance potential. Design trends were directed toward increased speed, efficiency, productivity, and safety. Generally speaking, the research and development effort has been evolutionary in nature and, with the exception of the transition to supersonic flight, little has occurred since the origin of flight that has drastically changed the basic design fundamentals of aircraft. However, this does not preclude the possibility of dramatic changes in the future since the products of research are frequently unpredictable. Advances should be expected and sought in improved aerodynamics (reduced drag, enhanced lift, flow field exploitation); propulsion (improved engine cycles, multimode engines, alternate fuels, alternate power sources); structures (new materials, manufacturing techniques); all with a view toward increased efficiency and utility.

Spearman, M. L.↗

NASA NTRS1983

Effects of wing and tail location on the aerodynamic characteristics of an airplane for Mach numbers from 0.25 to 4.63

Experimental investigations have been conducted to determine the effect of wing vertical position and horizontal-tail vertical and axial position on the static aerodynamic characteristics of a wing-body horizontal-tail configuration. The configurations investigated included the wing in a high, mid, or low position on the body with the horizontal tail in each of these vertical positions as well as in three axial positions. The closest position of the horizontal tail to the wing essentially provided on all-wing configuration. In addition, tests were made for the three wing positions with the horizontal tail removed. The tests were made in three different wind tunnels to provide data for a Mach number range from 0.25 to 4.63. The purpose of the investigation was to illustrate the strong effects of interference flow fields as a function of geometry and flight regime. An analysis of the results indicate some arrangements that might lead to aerodynamic problems and others in which the interference flow fields might be favorably exploited. The results suggest that a coplanar concept with a translating horizontal tail could potentially minimize the aerodynamic changes with Mach number and provide more optimum performance over the Mach number range.

Spearman, M. L.↗

NASA NTRS1983

An aerodynamic assessment of various supersonic fighter airplanes based on Soviet design concepts

The aerodynamic, stability, and control characteristics of several supersonic fighter airplane concepts were assessed. The configurations include fixed-wing airplanes having delta wings, swept wings, and trapezoidal wings, and variable wing-sweep airplanes. Each concept employs aft tail controls. The concepts vary from lightweight, single engine, air superiority, point interceptor, or ground attack types to larger twin-engine interceptor and reconnaissance designs. Results indicate that careful application of the transonic or supersonic area rule can provide nearly optimum shaping for minimum drag for a specified Mach number requirement. Through the proper location of components and the exploitation of interference flow fields, the concepts provide linear pitching moment characteristics, high control effectiveness, and reasonably small variations in aerodynamic center location with a resulting high potential for maneuvering capability. By careful attention to component shaping and location and through the exploitation of local flow fields, favorable roll-to-yaw ratios may result and a high degree of directional stability can be achieved.

Spearman, M. L.↗

NASA NTRS1983

Supersonic aerodynamic characteristics of a tail-control cruciform maneuverable missile with and without wings

The aerodynamic characteristics for a winged and wingless cruciform missile configuration were examined. The configuration had an ogive-cylinder body with a 3.5 caliber forebody; an overall length-to-diameter ratio of 11.667; and had cruciform tails that were trapezoidal in planform. Tests were made both with and without 72.9 degree cruciform delta wings. The investigation was made for Mach numbers from 1.50 to 4.63, roll attitudes of 0 degrees and 45 degrees, angles of attack from -4 degrees to 22 degrees, and tail control deflections from 10 degrees to -40 degrees.

Spearman, M. L.↗

NASA NTRS1983

Effect of external stores on the stability and control characteristics of a delta wing fighter model at Mach numbers from 0.60 to 2.01

An investigation has been made to determine the effects of external stores on the stability and control characteristics of a delta wing fighter airplane model at Mach numbers from 0.60 to 2.01 for a Reynolds number of 3.0 X 1 million per foot. The angle-of-attack range was from about -4 degrees to 20 degrees at a sideslip angle of 0 degrees for the transonic tests, and from about -4 degrees to 10 degrees at sideslip angles of 0 degrees and 3 degrees for the supersonic tests. In general, the results of the tests indicated no seriously detrimental effects of the stores on the stability and control characteristics of the model but did show an increase in the minimum drag level throughout the Mach number range. However, the drag-due-to-lift was such that for subsonic/transonic speeds, the drag at higher lifts was essentially unaffected and the indications are that the maneuvering capability may not be impaired by the stores.

Spearman, M. L.↗

NASA NTRS1983

The minimization of pylon-mounted store effects on air combat capability

Some effects of pylon-mounted missiles on aft-tail delta wing supersonic fighter concepts have been investigated. Whereas minimum drag penalties do occur with the addition of missiles, the effects at higher lifts, corresponding to maneuvering flight, are less severe and often favorable. Lower speeds and altitudes enhance the maneuvering capability and one-on-one air combat would probably tend to degenerate to subsonic speeds even though the combatants may be flying supersonic fighters. Higher speed (supersonic) flight might best be reserved for interceptors with long-range missiles where the weapon carriage effects at low angles of attack are of prime importance.

Spearman, M. L.↗

NASA NTRS1983

The role of wind tunnels in predicting sounding rocket aerodynamics

The nature of some cases of flow separation, flow-field interference, unusual vehicle shape or size, excessive deviations to high angular positions. Mach number induced effects, Reynolds number effects, and effects of protruberances on wind tunnel investigations of sounding rockets are illustrated.

Spearman, M. L.↗

NASA NTRS1983

An overview of the potential threat as related to missile requirements

Based on unclassified sources, a general review is presented of the perceived U.S.S.R. doctrine, force balances, production ratios, inventory growth, inventory items, and current actions. The extent to which the Soviets appear to be attempting to increase their sphere of influence through economic and political control as well as possible military control of land, sea, air, and space is considered. To offset such possibilities, certain areas of deterrent needs that the Western world might pursue are suggested. Particular emphasis is placed on the role of missiles as part of the deterrent needs.

Spearman, M. L.↗

NASA NTRS1982

Wind-tunnel studies of the effects of stimulated damage on the aerodynamic characteristics of airplanes and missiles

As an aid in assessing the aerodynamic effects of battle damage that might be sustained by military airplanes or missiles, several wind tunnel investigations were performed at the Langley Research Center in which damage was simulated with models by the removal of all or parts of the wing and tails. Results of the investigations indicate that the loss of a major part of the vertical tail will probably result in the loss of an airplane in any speed range. The loss of major parts of the horizontal tail generally results in catastrophic instability in the subsonic range but, at low supersonic speeds, and for some planform configurations at subsonic speeds, may allow stable flight to the extent that the airplane might return to friendly territory before the pilot must eject. The results further indicate that major damage to the wing, up to the point of the complete removal of one wing panel, and major damage to the horizontal tail may be sustained without necessarily causing the loss of the airplane or pilot.

Spearman, M. L.↗

NASA NTRS1981

Historical trend in the research and development of aircraft

Results are presented from a study of aircraft design trends undertaken to determine the relationship between research, development, test and evaluation and aircraft mission capability, requirements and objectives. It is shown that while in some cases a performance objective was the primary research driver, research was the driver in the formulation of objectives in others. Among the topics discussed are: (1) speed considerations such as compressibility, propulsion and test techniques; (2) airframe considerations such as swept, delta, trapezoidal and variable-sweep planforms and mission commonality; (3) research aircraft; (4) the recent impact of computer-aided design; (5) Soviet aircraft development approaches and (6) a comparison of Soviet and U.S. military aircraft design trends. Attention is given to experimental and prototype aircraft programs which, although cancelled, anticipated significant subsequent developments.

Spearman, M. L.↗

NASA NTRS1980

Supersonic flight - Past, present, and future

The first part of the article is devoted to the history of supersonic flight, with attention given to the first manned flight research program, and United States supersonic military programs. The rest of the article discusses the current Supersonic Cruise Research (SCR) program from the points of view of aerodynamics, structures, propulsion, emissions, systems studies, and technology implications.

Spearman, M. L.↗

NASA NTRS1980

Effects of wing and tail location on the aerodynamic characteristics of an airplane for Mach numbers from 0.25 to 4.63

An experimental investigation was conducted to determine the effect of wing vertical position and horizontal-tail vertical and axial position on the static aerodynamic characteristics of a wing-body-horizontal-tail configuration. The configurations investigated included the wing in a high, mid, or low position on the body with the horizontal tail in each of these vertical positions as well as in three axial positions. The closest position of the horizontal tail to the wing essentially provided an all-wing configuration. In addition, tests were made for the three wing positions with the horizontal tail removed. The tests were made in three different wind tunnels to provide data for a Mach number range from 0.25 to 4.63. The purpose of the investigation was to illustrate the strong effects of interference flow fields as a function of geometry and flight attitude and to provide a systematic data base that might be useful for correlation with various analytical techniques. The results indicate some arrangements that might lead to aerodynamic problems and others in which the interference flow fields might be favorably exploited. The results suggest that a coplanar concept with a translating horizontal tail could potentially minimize the aerodynamic changes with Mach number and provide more optimum performance over the Mach number range.

Spearman, M. L.↗

NASA NTRS1979

Historical development of worldwide supersonic aircraft

Aerodynamic problems in the development of supersonic aircraft, their solutions, and innovative design features are presented. Studies of compressibility, introduction of jets, supersonic phenomena, transonic drag and lift, longitudinal and directional stability, dynamic pressure fields, and advent of the supersonic fighter are discussed. The flight research aircraft such as the Bell X-1 and the Douglas-558, the century series models, reconnaissance aircraft, the multimission tactical fighter, and the current generation fighters such as F-16 and F-18 are described. The SCAT program is considered, along with supersonic developments in Great Britain, France, and USSR. It is concluded that the sonic boom still appears to be an inherent problem of supersonic flight that particularly affects overland commercial flight, and efforts continue for increased efficiency for economic and performance gains and increased safety for military and civilian aircraft.

Spearman, M. L.↗

NASA NTRS1979

Wind-tunnel studies of the effects of simulated damage on the aerodynamic characteristics of airplanes and missiles

In order to assess the effects on static aerodynamic characteristics of battle damage to an aircraft or missile, wind tunnel studies were performed on models from which all or parts of the wing or horizontal or vertical tail had been removed. The effects of damage on the lift, longitudinal stability, lateral stability and directional stability of a swept-wing fighter are presented, along with the effects of wing removal on the control requirements of a delta-wing fighter. Results indicate that the loss of a major part of the vertical tail will probably result in the loss of the aircraft at any speed, while the loss of major parts of the horizontal tail generally results in catastrophic instability at subsonic speeds but, at low supersonic speeds, may allow the aircraft to return to friendly territory before pilot ejection. Major damage to the wing may be sustained without the loss of aircraft or pilot. The loss of some of the aerodynamic surfaces of cruise or surface-to-air missiles may result in catastrophic instability or may permit a ballistic trajectory to be maintained, depending upon the location of the lost surface with respect to the center of gravity of the missile.

Spearman, M. L.↗

NASA NTRS1979

The role of wind tunnels in predicting sounding rocket aerodynamics

The aerodynamic characteristics of sounding rockets, in some cases, may be adequately determined by various estimating procedures, however, there are cases where these procedures fail and wind tunnel studies become necessary. The present paper deals with configurations of the latter type, for which the problems of concern include mismatched diameters between stages, mutual fin interference effects, fin alignment and orientation, body deflections between stages, boundary layer growth, and stability changes that occur as stages are dropped. Some characteristics related to separated flow, interference flow fields, and Reynolds number are examined.

Spearman, M. L.↗

NASA NTRS1979

Aerodynamic characteristics of missile configurations based on Soviet design concepts

The aerodynamic characteristics of several missile concepts are examined. The configurations, which are based on some typical Soviet design concepts, include fixed-wing missiles with either forward- or aft-tail controls, and wing-control missiles with fixed aft stabilizing surfaces. The conceptual missions include air-to-air, surface-to-air, air-to-surface, and surface-to-surface. Analytical and experimental results indicate that through the proper shaping and location of components, and through the exploitation of local flow fields, the concepts provide generally good stability characteristics, high control effectiveness, and low control hinge moments. In addition, in the case of some cruise-type missions, there are indications of the application of area ruling as a means of improving the aerodynamic efficiency. In general, a point-design philosophy is indicated whereby a particular configuration is developed for performing a particular mission.

Spearman, M. L.↗