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The results of a computer study on four roll-out guidance control laws and a nosewheel steering configuration is included herein. Beam convergence, ground speed, and crosswind effects were included in the simulation. (Author)

A brief review is made of those flow phenomena which affect the performance of high-speed craft in general. The comments made concern the broad areas of lifting and control surfaces, steering, and propulsion by high-speed propellers. (Author)

The interim Wheel/Track Convertible Test Rig, a uniquely suspended 8x8 wheeled vehicle that uses wrap-around tracks for improved performance, was tested in a variety of terrain conditions at Houghton, Michigan, and at Vicksburg, Mississippi, and in soil bins in a facility at Vicksburg. Tests were conducted to: evaluate the feasibility of the concept, determine if the track would stay on, observe interaction at the wheel-track interface to determine any possible slippage, determine ride and handling characteristics of the Wheel/ Track Test Rig, which uses powered road arm suspensions, and evaluate and compare performance of the Test Rig with that of other available vehicles in tests on trails, cross-country traverses, special terrain, and laboratory- prepared soils.

An experimental program to obtain quantitative data on how drivers utilize the performance and handling properties of their vehicles has been performed. Over one hundred drivers participated in the experiment, which consisted of self-paced driving through a specially-constructed proving ground handling course several times. Continuous measurements of primary input variables (steering wheel motions and brake pedal activity) and the principal vehicle responses (speed and lateral and longitudinal accelerations) were made throughout each trial. Total time in the course and incidents of failure to maintain path were also measured. Driving techniques (e.g., hand position on the steering wheel, foot used for braking) of the subjects, who were selected to provide an appropriate representation of the driving population with respect to age, sex, and years of driving experience, were subjectively observed., Prepared in cooperation with General Motors Proving Ground, Milford, Mich.

Dynamic course stability and turning performance of two naval ships, the DL-2 hull form and the ASR catamaran, are examined utilizing the Rotating-Arm Facility combined with a computer analysis. Based on test results of the DL-2 hull form and previous hydrodynamic data of various ship configurations, a computational procedure is developed to evaluate maneuvering performance of high-speed ships at the design stage from major hull parameters. Correlations between predictions and test results indicate the procedure can be effectively used as a design tool.

This report presents the results of all efforts to study the problem of wet runway control of the F-4 fighter aircraft. The hardware tested is as follows: Hytrol Mark II Brake Control System, Hytrol Mark III Brake Control System, Standard Main Tire, Dunlop Main Tire, Sommer Main Tire, BFG Main Tire, USAF Main Tire, Dual Mode Hydro-Electrical Control Steering System, Standard Nose Tire, Dunlop Nose Tire, BFG Nose Tire, and USAF Nose Tire. In addition to this, testing was also completed to determine the variation in main tire spinup time with touchdown sink rate and the effect resulting from 50% worn main tires.

The study was conducted to determine dependency of steering efforts on air pressure in the tires. Readings were taken with the front wheels suspended, stopped on a hard surface and with the vehicle in motion, both with the hydraulic steering booster in operation and disengaged. (Author), Trans. of Avtomobilnaya Promshlennost (USSR) n4 p22-23 1971.

Trailers with automobile-type front-wheel drive have a tendency to horizontal transverse wobble. Theoretical and experimental investigations indicated that critical speeds of trailer-trains, which were used as parameters of stability of straight-line motion, had a direct relationship to the angle of casters in steering mechanisms. The results also indicated that clearance in the couplings of the steering mechanism has an effect on the magnitude of transverse vibration., Trans. of Avtomobilnaya Promyshlennost (USSR) n10 p14-16 1971.

The report summarizes results of an exploratory development program to generate the Artillery Towing Lightweight Auxiliary System (ATLAS) concept. The concept was designed to enhance the effective deployment of towed artillery systems in the forward battle areas, especially the XM198 155mm HOwitzer and other equipment in this category. The lightweight ATLAS is helicopter transportable and is capable of supplying auxiliary power such as electricity, compressed air and hydraulics for associated equipment support. The ATLAS also provides essential logistic support by carrying a limited supply of all required ammunition components. Front whell drive and steer is provided when the ATLAS is in the solo mode. The ATLAS can pivot steer about the center of its drive axle, when coupled to the howitzer, thereby traversing the weapon about its firing base. (Modified author abstract)

This report describes an analog computer maneuvering simulation of a destroyer study ship. The mathematical model which is used includes the ship propulsion machinery dynamics and the ship equations of motion. The model couples the ship propulsion dynamics equations with nonlinear maneuvering equations. The power plant representation consists of a simplified mathematical model of a General Electric LM2500 gas turbine engine and is primarily an engine mapping of engine torque versus engine speed using fuel flow rate as a parameter. The simulation is used to accurately predict slow transients in ship speed during maneuvers resulting from slow increases in the fuel flow rate to the gas turbine. (Modified author abstract)

An investigation of the maneuvering control of two ships in the replenishment at sea operation, seen as a multivariable system, is carried out. The mathematical model of the ships motion in three degrees of freedom is established and implemented for the formation of digital computer programs and approximated for the study of steady state decoupling. Using parameter optimization techniques, the necessary control loops are designed with the aid of a digital computer. The station keeping problem of underway operation is simulated and the results compared and analyzed. (Author)

On the evening of November 7, 1972, the SS AFRICAN NEPTUNE departed the State Docks at Brunswick, Ga. About 13 minutes later, the ship struck the Sidney Lanier Bridge at a point about 350 feet south of the channel centerline. Three sections of the bridge and 10 vehicles waiting to pass over the span fell into the river. As a result, 10 persons died and 11 were injured, and the bridge, part of U.S. Route 17, was closed to highway traffic for about 6 months. Repair costs amounted to about $1,300,000. Damage to the ship was relatively minor. The National Transportation Safety Board determines that the probable cause of the collision of the SS AFRICAN NEPTUNE with the Sidney Lanier Bridge was (1) the failure of the helmsman to apply the correct rudder in response to two helm orders; (2) the failure of the third mate, master, and pilot to discover the first error; and (3) the delay by the third mate, master, and pilot in detecting the second error., Prepared in cooperation with National Transportation Safety Board, Washington, D.C.

The U.S. SST prototype commercial airliner under development from 1967 to 1971 employed redundant flight-critical control systems as an essential part of the airplane's airworthiness. The flight control system electronics were analog for the flight-critical stability augmentation functions and digital for the automatic flight control functions. The digital system, through an automated preflight test function, also served to establish the integrity of the flight- critical elements. The SST program was terminated before these systems became operational. This study deals with the mechanization of redundant electronic systems. Specifically, the study evaluates analog and digital electronic designs for implementing a triplex fail-operational flight-critical control system. The primary subjects studied were analog and digital systems' multiple failure fail-operational capabilities and preflight integrity check requirements. This document deals with analytical and laboratory performance evaluations of the systems studied. Specific areas covered include basic filter processing, closed loop operation, fault tolerant performance, sensor signal selection/failure detection, and digital computer timing and memory relationships., Report on SST Technology Follow-On Program. See also AD0913365 and ADB000281.

Test vehicles incorporated nine primary and 27 secondary product improvement items. Purpose of the test was to determine ride and handling characteristics; compliance with specified technical performance requirements; and durability and maintenance support requirements. The ride and handling characteristics of the M151 with MIRS were an improvement compared to the production M151A1.

The Model 347, a derivative of the CH-47 transport helicopter, was tested. Performance, handling qualities, vibration and noise characteristics were evaluated to determine the improvements provided by incorporation of advanced technology systems in a large tandem-rotor transport helicopter. Compliance with the provisions of the contract statement of work and with military specifications, MIL-H-8501A and MIL-A-8806A, was determined. Several shortcomings identified during the testing were corrected by the contractor after the testing was completed. The effects of these corrections were evaluated during additional testing conducted on 11 and 12 August 1971. Level flight performance and out-of-ground-effect hover performance were significantly improved over that of the CH-47C helicopter. The excellent static longitudinal stability characteristics enhanced the mission capability of the aircraft. The steering and glide-path modes of the automatic flight path control system worked satisfactorily and reduced the pilot workload in instrument flight conditions. Cockpit noise and vibration characteristics were noticeably improved over those of the CH-47C.

The 120-foot-diameter Haystack antenna operates at X-band and is used for satellite communications, radio astronomy, and radar astronomy. Haystack will be used to study stars, planets, the sun, the moon, and earth satellites. In order to point the antenna to within 1/10 beamwidth (22 seconds of arc) and to provide flexible control and data processing for diverse users, a digital computer has been tightly integrated into the control system. The parameters of an experiment and computer control are arranged via simple operator discourse through a keyboard/printer. The computer system can simultaneously direct the antenna, process receiver signal data, drive convenient operator displays, and permit operator discourse. Thus, processed signal data may be observed in real time, and modifications to the experiment may be rapidly implemented. The computer control system has been completed and is in full operation.

The report concerns the hydrodynamic forces and moments produced by a bow thruster. Several broad problem areas are discussed and the extent of present-day knowledge indicated. These include general duct arrangement, duct shape, and impeller design. A step-by-step design procedure is outlined that permits the selection of a practical bow thruster. This procedure is described for a minimum number of operational requirements; e.g., single bow thruster, a specified turning rate when the ship is dead in the water, and a duty cycle that requires thruster operation at ahead speed for control capability in canals, harbors and other restricted waterways.

The report concludes that a computer simulation of ship underway replenishment can be developed. A system of linear equations of motion for describing two ships maneuvering on essentially parallel courses is chosen as the basic equations for the mathematical model to be used in the computer simulation. The derivation of these linear equations is presented. A better representation using nonlinear equations of motion will be considered in a later phase of the study.

This report covers the development, test, and evaluation of a maneuverable personnel parachute canopy assembly modification. The canopy assembly tested was constructed from the basic 35-foot diameter extended skirt canopy assembly, AF 49J7141-2, used with Personnel Parachute, Troop-Back, 35- Foot Diameter, Type T-10, A/P28S-14. A TU type of orifice was installed in the canopy, and the slip risers utilized with the maneuverable personnel parachute assemblies, A/P28S-10 (Static Line) and A/P28S-13 (Free Fall) for steering the parachute, were replaced by risers, AF 59C6174, and control lines. The results of this test and evaluation program indicate that the canopy assembly modification provides more maneuverability and a better turn rate performance than that currently obtainable with the maneuverable personnel parachute assemblies, Types A/P28S-10 and A/P28S-13.

The purpose of this project was the design and construction of three mobility test rigs as postulated by the Vicksburg Mobility Exercise 'A' document, dated February 1965. The construction of these test rigs was undertaken to generate the hardware necessary to prove the theory, advanced in the Exercise 'A' document, that vehicles can be built to operate in a specified environment using existing techniques in mobility science. Covered in this report is an account of the design, construction, and initial testing of the three machines.

A directional 400-Hz source was developed for the Navy research program on undersea surveillance. The source can be operated over a 100-Hz frequency band from 350 to 450 Hz with a maximum available source level of 147 dB versus 1 dyne per square centimeter at 1 yard (dB//1 dyne/cm squared at 1 yd) . The system is installed in a converted T-2 class A-2 tanker, the major modification being a well cut through the main deck and keel approximately at midship through which the transducer array is lowered to operating depth. The system includes winches and cable-handling machinery for lowering the approximately 800,000 pound transducer array to a 1200-foot depth. Interaction between transducer elements in the multielement array was a major problem in the system development. Although the effect of interaction was reduced, it was not completely overcome. The principal effect of the interaction was to cause excessive fatigue in transducer elements, necessitating reduction of input power to prevent transducer failure. A modified version of the element was developed which can withstand the larger displacement associated with interaction. If this element were used in the array, it is anticipated that a source level of approximately 156 dB could be obtained. This assumes that the pressure-release system required to suppress the back radiation of the array could be modified to withstand the higher acoustic intensity.

The engineering design handbook series of the Army Materiel Command is a coordinated series of handbooks containing basic information and fundamental data useful in the design and development of Army materiel and systems. The handbooks are authoritative reference books of practical information and quantitative facts helpful in the design and development of Army materiel so that it will meet the tactical and the technical needs of the Armed Forces. The Automotive Assembly constitutes the first of a planned automotive series of handbooks concerned with the design of military automotive vehicles., Supersedes AMCP-706-355 pamphlet dated 31 Dec 1962.

The two dimensional trajectory of a radial homing gliding parachute in a uniform wind is presented. The kinematics of the motion is discussed generating two first order differential equations which are separated and solved by direct integration. The resulting expression functionally relates the radial position of the parachute to the instantaneous value of the azimuth angle. Using this result, an exact solution for time in terms of space coordinates is obtained.

Display motion relationships for attitude and steering indicators have always been controversial issues in flight display design. The questions involve whether the pilot thinks the aircraft is moving relative to the outside world or the outside world is moving relative to the airplane. The pertinent information, obtained through both experience and formal experimentation, is reviewed. An alternative to the standard forms of attitude presentation employs the frequency separation principle. The problems considered when doing experimental investigations on flight displays are subject pools, research environments, flight tasks, and performance measures. Research requirements necessary to solve the longstanding questions on display motion relationships are presented.

A description is given of ten non-major subprograms in the Haystack Pointing System. These programs all operate in the real-time environment, but in a sense are embellishments to the system proper inasmuch as they are by design either utilitarian to system operation or perform minor system functions. The additional system capabilities provided by this set of subprograms include: alteration of memory locations; modification of certain system parameters; constant monitoring of selectable memory locations; pointing of the antenna to any azimuth and elevation or right ascension and declination; outputting of certain planning information 'on-line'; strip chart recording; magnetic tape recording; high-speed printer interfacing and Westford/Millstone intersite coupling.

A set of eight non-real-time service programs was written in support of the Haystack Pointing System to facilitate system maintenance and updating. Peripheral functions afforded by this set of programs include: (1) format conversion and remote printing facility of the SPURT assembler printer outputs 210, 211 and 212; (2) magnetic tape dumping; (3) 'effective' punched card input to SPURT assembler; (4) CalComp plotting of system output; (5) punched card equivalents of Common Storage Allocation Tape; (6) automatic program loading with bootstrap tape generation facilities; (7) magnetic tape duplication; and (8) automatic updating of system tapes., See also AD629936.

The report describes the operation and organization of the digital equipment associated with the Univac 490 pointing computer at Haystack. All of the input/output equipment connected to the U490 is discussed with the major emphasis being placed on that equipment associated with pointing the antenna.

A general-purpose interface has been constructed for Channel 5 of the Haystack Univac 490 digital computer. Data inputs are from the radiometer and a general-purpose A/D converter while outputs are a display of right ascension, declination, and hour angle, a CRT display and strip chart recorder, and control of the radiometer and other general-purpose functions.

The Haystack Pointing System, implemented on the Univac 490 computer, is comprised of some thirty odd subprograms which go to make up an operating system and a utility system. The domain of this memorandum is limited to the description of the control of the operating system as vested in the master control and timing programs and in the computer itself via its external and internal interrupt capabilities. In the discussion of the programmed control function are included the real-time and simulation modes of the system, the man- machine communication scheme, the experiment set-up procedures, a step by step description of the entire system cycle, the plug-in program concept as utilized in connection with the celestial computation programs and data processing programs as well as other system facets as they relate to control. Certain procedural matters which bear on the control structure are discussed., See also AD622666, AD629936, AD630193.

Haystack Pointing System consists of hardware and software which points the Haystack 120-foot X-band antenna dish with great accuracies. The Satellite Acquisition program, described in this report, generates acquisition scans and searches for target returns. Once the target has been sighted, the program tracks the target by conical scanning. After acquisition, time correction can be made in the orbit computations.

Some interceptor missiles as presently formulated possess a programmed thrust magnitude history with a gimbaled engine to provide steering. We examine one such missile to determine whether performance can be improved if we allow a variable thrust magnitude together with engine gimbaling to provide control. Two trajectory optimization programs were written to provide an initial answer to this problem. Preliminary results indicate reductions in the time to intercept by as much as thirty per-cent over that obtained by the presently used guidance scheme. With tuning of the programs it seems reasonable to expect even greater improvements and further investigation seems warranted., Purchase Order 3-0014.

The USS PLYMOUTH ROCK (LSD 29) is a high speed, steam turbine, twin-screw, twin rudder dock ship built by the Ingalls Shipbuilding Corporation, Pascagoula, Mississippi. The tactical trials were authorized by the Bureau of Ships, and were conducted on 23, 24, and 25 September 1955, off Rockland, Maine. Standard 540 degree turns were made using various approach speeds and rudder angles. Special turns were made while backing the inboard shaft. All turns were made with right rudder except for two check left turns. Acceleration runs were made to determine the relationship between time, speed and reach. Other runs were made to determine the relationship of the above quantities in decelerating from several speeds with varying throttle settings. During the acceleration and deceleration runs the throttles were manipulated to change the RPM as rapidly as permissible, either ahead or astern, without reducing the main steam line pressure at the throttles below the minimum established operating pressure. Special deceleration runs were made with five second and ten second delays between closing the ahead throttle and opening the astern throttle.

A parametric study of twin and triple-screw propulsion systems for large icebreakers is conducted with respect to technical properties and feasibility limits. The study is devoted to the following aspects in particular: Bollard thrust, ahead, conventional propeller; Bollard thrust, astern, conventional propeller; Bollard thrust ahead and astern, special compromise propeller, designed for astern operation; Propulsive efficiency at advance speed of 1 knot; Propulsive efficiency, free running at 18 knots; Radial and axial clearances between propellers and hull; Steering and maneuverability; Propeller excited hull and shaft vibrations; Propeller strength; Cavitation--further, the effect of the following parameters had to be considered: Blade number, three versus four blades; Hub size, solid and detachable blade screws; Propeller diameter; Area and power splitting ration, 1:1:1 versus 1:2:; Powering (SHP).

Contents: The Automatic Recording and Analysis of Magnetic Fields; Some Dielectric Properties of an Epoxide Resin; Automatic Heading and Track Keeping Control; Research and Development Management in the Navy Department; Welding on Wet Primary Circuit Systems Type 304 Stainless Steel; The End of the Imperial Defence College; Boundary Layer Additives to Reduce Ship Resistance.

This report considers the problem of controlling both the attitude and angular velocities of an axially symmetric spacecraft while minimizing the maneuver duration. In particular, various combinations of thrust limited reaction jets are employed to properly orient a spinning space body with respect to specified reference directions starting from known initial conditions of the vehicle's attitude and angular rates. Five control jet configurations are considered: two gimballed systems where torques can be applied about, (1) any axis in a plane normal to the axis of symmetry, (2) two perpendicular non- rotating axis in a plane normal to the axis of symmetry; and three body-fixed configurations where the thrusters are immobile relative to the vehicle and can provide both positive and negative or only positive (negative) control torques about one or both of the vehicle's transverse axis. The control systems are realizable from a hardware standpoint and the corresponding optimal controls can be classified as: (1) a continuous function of time, (2) bang-bang, (3) on-off, and (4) a combination of (1 and 2) or (2 and 3).

The fields of adaptive control and guidance are searched for techniques that can be beneficially applied to the design of guidance systems for tactical missiles. A large number of existing adaptive control techniques are investigated and new methods which are suited to the needs of missile control systems, are proposed. The feasibility of promising autopilot design procedures is demonstrated through computer simulations, using realistic time- varying airframe dynamics. Guidance techniques for tactical missiles are also reviewed and a number of steering laws, derived from optimal control theory, are evaluated. Quantitative comparisons are made between different guidance laws on the basis of intercept accuracy and control effort expended., See also Volume 2, AD879285.

The fields of adaptive control and guidance are searched for techniques that can be beneficially applied to the design of guidance systems for tactical missiles. The report is published in two volumes containing four basic parts -- Introduction (which includes the summary and conclusions for the entire report), Adaptive Control Theory, Adaptive Control Applications, and Guidance. The first two parts constitute Volume I and the remainder together with several appendices compose Volume II., See also Volume 1, AD879284

The review of a particular theoretical tire dynamics model is presented leading to a prediction of side thrust as the result of combined slip angle and camber angle with load as the major parameter. An experimental program to test these predictions has been accomplished using 7.00-16 military tires mounted on a solid axle, unsprung toe-in trailer. The theoretical predictions are compared with the experimental results.

This Engineering Test Procedure describes test methods and techniques for evaluating the technical performance and characteristics of Aircraft Towing Tractors (Wheeled Type) and for determining the suitability of the test item to be subjected to service testing. The evaluation is related to criteria expressed in applicable Qualitative Materiel Requirements (QMR), Small Development Requirements (SDR), Technical Characteristics (TC), and other appropriate design requirements and specifications.

An analytical method combining simplified potential flow theory and low aspect-ratio wing theory with empirical modifications for a real viscous fluid is used to predict the stability derivatives (first order hydrodynamic force and moment derivatives) of a family of hulls in order to estimate the dependence of geometric characteristics of course stability and turning or steering qualities. The hulls are Taylor Standard Series forms with after deadwood re moved and have the same length and prismatic coefficient but varying length-draft and beam draft ratios and skeg area. Comparison between the values calculated by this method and those obtained from experimental measurements shows good agreement. The analytical method can predict the relative effects of the geometrical characteristics. Calculated magnitudes are slightly different from the experimental. How ever, since the hulls tested have the same prismatic, the empirical modification for the rotary moment derivative which is a function of prismatic coefficient was fully tested.

The derivation of the several forms of the linear-tangent steering program is presented. The mathematical form of these equations is shown to be totally independent of the variation of thrust acceleration with time. Insofar as position and velocity changes caused by thrust only are concerned, the linear-tangent law is the precise mathematical optimum. Its utility and advantages are explained, as well as its limitations. The derivation of the thrust-direction steering law is given, but guidance equations are not.

The major effort during the three-month period was directed toward the detailed design and construction of a beam steerer, beam-steering pick-off device, control circuits for the image dissector, and search/track circuits. All of these items are under construction and will be completed in time for an early test of the search/track capabilities of the system. Design work on the optical head is continuing.

A literature survey, including 314 references, is presented for the fields of automobile and airplane wheel shimmy. The coverage is believed to be relatively complete insofar as the available, published world-wide literature is concerned. In addition to the bibliographic listings, a short review and appraisal of the contents of each reference is given. The report contains indices according to subject, author and nationality of the contributions; the periodical coverage of the survey is also given in detail. A general survey of the problems of automobile and airplane wheel shimmy is included, which highlights the principal trends and contributions to the subject over the years. Finally, on the basis of the survey indications, recommendations are advanced for further research and development in the field. (Author)

The following systems and subsystems are being developed as parts of the Steerable Null Project: (1) Basic null steering system; (2) Memory address register monitor subsystem; (3) Two DIMUS system; (4) Input filter subsystems; (5) Input simulator test unit; (6) Hydrophones and hydrophone array; and (7) Recorder - display system., Includes Rept. no. MPL-TM-162 as appendix A in this report. See also AD-377 715.

This report presents the results of cavitation tests and shows the effects of cavitation on a 9-inch orbital diameter cycloidal propeller in the 24-inch variable-pressure water tunnel at the Naval Ship Research and Development Center. Six blades were used and the blade motion was pure cycloidal. Two pitch ratios and two steering angles for one of the pitch ratios were investigated over a range of advance coefficients and cavitation numbers.

Open water test results of four high-pitch cycloidal propellers are reported herein. They were tested at various steering angles over a range of advance coefficients. The results show high thrust and maneuvering capability with these propellers at high advance - coefficients indicating the potential for high-speed application of these propellers. (Author)

This report describes measurements of the mean lateral force and yawing moment exerted by oblique regular waves on a free-to-oscillate Series 60, 0.60 block coefficient model. It also presents measurements made of the lateral force and moment on the same model towed in calm water at various yaw angles. The possibility of using these data to predict the leeway angle for a free model in oblique waves is investigated, and it is shown that such a procedure may lead to errors, especially in the case of short wavelengths.

A series of tests was conducted with a Lunar Roving Vehicle (LRV) wheel operating at yaw angles ranging from -5 to +90 deg. The load was varied from 42 to 82 lb (187 to 365 N), and the speed was varied from 3.5 to 10.0 ft/sec (1.07 to 3.05 m/sec). It was noted that speed had an effect on side thrust and rut depth. Side thrust, rut depth, and skid generally increased as the yaw angle increased. For the range of loads used, the effect of load on performance was not significant.

The patent concerns a glidable personnel-type parachute having a conventional canopy and shroud lines connected to a pair of forward and aft risers. A selected number of adjacent shroud lines in the aft risers can be released by the parachutist simply by pulling on a release lanyard to create a scalloped air-venting portion in the canopy skirt. The release lanyard may also be connected to the shroud lines on each side of the scalloped canopy portion to enable the parachute to be steered in its gliding movement.

The primary object of this invention is to provide means and a method of steering a plurality of land vehicles, coupled together in train formation, over rough terrain from a control vehicle.